Boost-Commit :

Date view	Thread view	Subject view	Author view

Subject: [Boost-commit] svn:boost r76974 - in trunk: boost/context boost/context/detail libs/context libs/context/build libs/context/doc libs/context/doc/pdf libs/context/example libs/context/example/asio libs/context/example/continuation libs/context/example/enumerator libs/context/performance libs/context/src libs/context/src/asm libs/context/test
From: oliver.kowalke_at_[hidden]
Date: 2012-02-11 08:05:05

Next message: barend.gehrels_at_[hidden]: "[Boost-commit] svn:boost r76975 - trunk/boost/geometry/algorithms/detail/overlay"
Previous message: dnljms_at_[hidden]: "[Boost-commit] svn:boost r76973 - trunk/libs/iostreams/test"

Author: olli
Date: 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
New Revision: 76974
URL: http://svn.boost.org/trac/boost/changeset/76974

Log:
initial commit of boost.context

Added:
   trunk/boost/context/
   trunk/boost/context/all.hpp (contents, props changed)
   trunk/boost/context/context.hpp (contents, props changed)
   trunk/boost/context/detail/
   trunk/boost/context/detail/config.hpp (contents, props changed)
   trunk/boost/context/detail/context_base.hpp (contents, props changed)
   trunk/boost/context/detail/context_object.hpp (contents, props changed)
   trunk/boost/context/detail/fcontext_arm.hpp (contents, props changed)
   trunk/boost/context/detail/fcontext_i386.hpp (contents, props changed)
   trunk/boost/context/detail/fcontext_i386_win.hpp (contents, props changed)
   trunk/boost/context/detail/fcontext_mips.hpp (contents, props changed)
   trunk/boost/context/detail/fcontext_ppc.hpp (contents, props changed)
   trunk/boost/context/detail/fcontext_x86_64.hpp (contents, props changed)
   trunk/boost/context/detail/fcontext_x86_64_win.hpp (contents, props changed)
   trunk/boost/context/fcontext.hpp (contents, props changed)
   trunk/boost/context/flags.hpp (contents, props changed)
   trunk/boost/context/stack_allocator.hpp (contents, props changed)
   trunk/boost/context/stack_utils.hpp (contents, props changed)
   trunk/libs/context/
   trunk/libs/context/build/
   trunk/libs/context/build/Jamfile.v2 (contents, props changed)
   trunk/libs/context/doc/
   trunk/libs/context/doc/Jamfile.v2 (contents, props changed)
   trunk/libs/context/doc/acknowledgements.qbk (contents, props changed)
   trunk/libs/context/doc/asio.qbk (contents, props changed)
   trunk/libs/context/doc/config.qbk (contents, props changed)
   trunk/libs/context/doc/context.qbk (contents, props changed)
   trunk/libs/context/doc/context.xml (contents, props changed)
   trunk/libs/context/doc/context_ref.qbk (contents, props changed)
   trunk/libs/context/doc/continuation.qbk (contents, props changed)
   trunk/libs/context/doc/enumerator.qbk (contents, props changed)
   trunk/libs/context/doc/examples.qbk (contents, props changed)
   trunk/libs/context/doc/fcontext.qbk (contents, props changed)
   trunk/libs/context/doc/overview.qbk (contents, props changed)
   trunk/libs/context/doc/pdf/
   trunk/libs/context/doc/pdf/arm-aapcs.pdf (contents, props changed)
   trunk/libs/context/doc/pdf/arm-linux-aapcs.pdf (contents, props changed)
   trunk/libs/context/doc/pdf/iso_c99.pdf (contents, props changed)
   trunk/libs/context/doc/pdf/mips-o32.pdf (contents, props changed)
   trunk/libs/context/doc/pdf/ppc32-sysv.pdf (contents, props changed)
   trunk/libs/context/doc/pdf/ppc64-sysv.pdf (contents, props changed)
   trunk/libs/context/doc/pdf/x86_32-sysv.pdf (contents, props changed)
   trunk/libs/context/doc/pdf/x86_64-sysv.pdf (contents, props changed)
   trunk/libs/context/doc/performance.qbk (contents, props changed)
   trunk/libs/context/doc/rationale.qbk (contents, props changed)
   trunk/libs/context/doc/reference.qbk (contents, props changed)
   trunk/libs/context/doc/stack_ref.qbk (contents, props changed)
   trunk/libs/context/doc/tested.qbk (contents, props changed)
   trunk/libs/context/doc/todo.qbk (contents, props changed)
   trunk/libs/context/example/
   trunk/libs/context/example/Jamfile.v2 (contents, props changed)
   trunk/libs/context/example/asio/
   trunk/libs/context/example/asio/continuation.h (contents, props changed)
   trunk/libs/context/example/asio/echo_client.cpp (contents, props changed)
   trunk/libs/context/example/asio/echo_server.cpp (contents, props changed)
   trunk/libs/context/example/base_api.cpp (contents, props changed)
   trunk/libs/context/example/continuation/
   trunk/libs/context/example/continuation/continuation.h (contents, props changed)
   trunk/libs/context/example/continuation/echo.cpp (contents, props changed)
   trunk/libs/context/example/continuation/parallel.cpp (contents, props changed)
   trunk/libs/context/example/do_return.cpp (contents, props changed)
   trunk/libs/context/example/enumerator/
   trunk/libs/context/example/enumerator/enumerate_string.cpp (contents, props changed)
   trunk/libs/context/example/enumerator/enumerate_tree.cpp (contents, props changed)
   trunk/libs/context/example/enumerator/enumerator.h (contents, props changed)
   trunk/libs/context/example/enumerator/fringe.cpp (contents, props changed)
   trunk/libs/context/example/enumerator/power.cpp (contents, props changed)
   trunk/libs/context/example/enumerator/tree.h (contents, props changed)
   trunk/libs/context/example/exit.cpp (contents, props changed)
   trunk/libs/context/example/float.cpp (contents, props changed)
   trunk/libs/context/example/link.cpp (contents, props changed)
   trunk/libs/context/example/swap.cpp (contents, props changed)
   trunk/libs/context/example/transfer.cpp (contents, props changed)
   trunk/libs/context/example/unwind.cpp (contents, props changed)
   trunk/libs/context/performance/
   trunk/libs/context/performance/Jamfile.v2 (contents, props changed)
   trunk/libs/context/performance/bind_processor.hpp (contents, props changed)
   trunk/libs/context/performance/bind_processor_aix.cpp (contents, props changed)
   trunk/libs/context/performance/bind_processor_freebsd.cpp (contents, props changed)
   trunk/libs/context/performance/bind_processor_hpux.cpp (contents, props changed)
   trunk/libs/context/performance/bind_processor_linux.cpp (contents, props changed)
   trunk/libs/context/performance/bind_processor_solaris.cpp (contents, props changed)
   trunk/libs/context/performance/bind_processor_windows.cpp (contents, props changed)
   trunk/libs/context/performance/performance.cpp (contents, props changed)
   trunk/libs/context/performance/performance.hpp (contents, props changed)
   trunk/libs/context/performance/performance_gcc_i386.hpp (contents, props changed)
   trunk/libs/context/performance/performance_gcc_x86-64.hpp (contents, props changed)
   trunk/libs/context/performance/performance_msvc_i386.hpp (contents, props changed)
   trunk/libs/context/src/
   trunk/libs/context/src/asm/
   trunk/libs/context/src/asm/fcontext_arm_aapcs_elf_gas.S (contents, props changed)
   trunk/libs/context/src/asm/fcontext_i386_ms_pe_masm.asm (contents, props changed)
   trunk/libs/context/src/asm/fcontext_i386_sysv_elf_gas.S (contents, props changed)
   trunk/libs/context/src/asm/fcontext_mips32_o32_elf_gas.S (contents, props changed)
   trunk/libs/context/src/asm/fcontext_ppc32_sysv_elf_gas.S (contents, props changed)
   trunk/libs/context/src/asm/fcontext_ppc64_sysv_elf_gas.S (contents, props changed)
   trunk/libs/context/src/asm/fcontext_x86_64_ms_pe_masm.asm (contents, props changed)
   trunk/libs/context/src/asm/fcontext_x86_64_sysv_elf_gas.S (contents, props changed)
   trunk/libs/context/src/asm/fcontext_x86_64_sysv_macho_gas.S (contents, props changed)
   trunk/libs/context/src/fcontext.cpp (contents, props changed)
   trunk/libs/context/src/seh.cpp (contents, props changed)
   trunk/libs/context/src/stack_allocator_posix.cpp (contents, props changed)
   trunk/libs/context/src/stack_allocator_windows.cpp (contents, props changed)
   trunk/libs/context/src/stack_utils_posix.cpp (contents, props changed)
   trunk/libs/context/src/stack_utils_windows.cpp (contents, props changed)
   trunk/libs/context/test/
   trunk/libs/context/test/Jamfile.v2 (contents, props changed)
   trunk/libs/context/test/test_context.cpp (contents, props changed)

Added: trunk/boost/context/all.hpp
==============================================================================
--- (empty file)
+++ trunk/boost/context/all.hpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,16 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_CONTEXTS_ALL_H
+#define BOOST_CONTEXTS_ALL_H
+
+#include <boost/context/context.hpp>
+#include <boost/context/fcontext.hpp>
+#include <boost/context/flags.hpp>
+#include <boost/context/stack_allocator.hpp>
+#include <boost/context/stack_utils.hpp>
+
+#endif // BOOST_CONTEXTS_ALL_H

Added: trunk/boost/context/context.hpp
==============================================================================
--- (empty file)
+++ trunk/boost/context/context.hpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,320 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_CONTEXTS_CONTEXT_H
+#define BOOST_CONTEXTS_CONTEXT_H
+
+#include <boost/assert.hpp>
+#include <boost/bind.hpp>
+#include <boost/config.hpp>
+#include <boost/cstdint.hpp>
+#include <boost/move/move.hpp>
+#include <boost/preprocessor/repetition.hpp>
+#include <boost/type_traits/is_convertible.hpp>
+#include <boost/type_traits/remove_reference.hpp>
+#include <boost/utility/enable_if.hpp>
+
+#include <boost/context/detail/context_base.hpp>
+#include <boost/context/detail/context_object.hpp>
+#include <boost/context/flags.hpp>
+#include <boost/context/stack_allocator.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace contexts {
+
+class context
+{
+private:
+ typedef detail::context_base::ptr_t base_ptr_t;
+
+ base_ptr_t impl_;
+
+ BOOST_MOVABLE_BUT_NOT_COPYABLE( context);
+
+#ifndef BOOST_NO_RVALUE_REFERENCES
+ template< typename Allocator >
+ static base_ptr_t make_context_(
+ void( * fn)(), std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return, Allocator const& alloc)
+ {
+ return base_ptr_t(
+ new detail::context_object< void(*)(), Allocator >(
+ fn, alloc, size, do_unwind, do_return) );
+ }
+
+ template< typename Allocator >
+ static base_ptr_t make_context_(
+ void( * fn)(), std::size_t size, flag_unwind_t do_unwind, context & nxt, Allocator const& alloc)
+ {
+ BOOST_ASSERT( nxt);
+ return base_ptr_t(
+ new detail::context_object< void(*)(), Allocator >(
+ fn, alloc, size, do_unwind, nxt.impl_) );
+ }
+
+ template< typename Fn, typename Allocator >
+ static base_ptr_t make_context_(
+ Fn && fn, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return, Allocator const& alloc)
+ {
+ return base_ptr_t(
+ new detail::context_object< typename remove_reference< Fn >::type, Allocator >(
+ fn, alloc, size, do_unwind, do_return) );
+ }
+
+ template< typename Fn, typename Allocator >
+ static base_ptr_t make_context_(
+ Fn && fn, std::size_t size, flag_unwind_t do_unwind, context & nxt, Allocator const& alloc)
+ {
+ BOOST_ASSERT( nxt);
+ return base_ptr_t(
+ new detail::context_object< typename remove_reference< Fn >::type, Allocator >(
+ fn, alloc, size, do_unwind, nxt.impl_) );
+ }
+#else
+ template< typename Fn, typename Allocator >
+ static base_ptr_t make_context_(
+ Fn fn, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return, Allocator const& alloc)
+ {
+ return base_ptr_t(
+ new detail::context_object< Fn, Allocator >(
+ fn, alloc, size, do_unwind, do_return) );
+ }
+
+ template< typename Fn, typename Allocator >
+ static base_ptr_t make_context_(
+ Fn fn, std::size_t size, flag_unwind_t do_unwind, context & nxt, Allocator const& alloc)
+ {
+ BOOST_ASSERT( nxt);
+ return base_ptr_t(
+ new detail::context_object< Fn, Allocator >(
+ fn, alloc, size, do_unwind, nxt.impl_) );
+ }
+
+ template< typename Fn, typename Allocator >
+ static base_ptr_t make_context_(
+ BOOST_RV_REF( Fn) fn, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return, Allocator const& alloc)
+ {
+ return base_ptr_t(
+ new detail::context_object< Fn, Allocator >(
+ fn, alloc, size, do_unwind, do_return) );
+ }
+
+ template< typename Fn, typename Allocator >
+ static base_ptr_t make_context_(
+ BOOST_RV_REF( Fn) fn, std::size_t size, flag_unwind_t do_unwind, context & nxt, Allocator const& alloc)
+ {
+ BOOST_ASSERT( nxt);
+ return base_ptr_t(
+ new detail::context_object< Fn, Allocator >(
+ fn, alloc, size, do_unwind, nxt.impl_) );
+ }
+#endif
+
+public:
+ typedef void ( * unspecified_bool_type)( context ***);
+
+ static void unspecified_bool( context ***) {}
+
+ context() :
+ impl_()
+ {}
+
+#ifndef BOOST_NO_RVALUE_REFERENCES
+# ifdef BOOST_MSVC
+ template< typename Fn >
+ context( Fn & fn, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return) :
+ impl_( make_context_( static_cast< Fn & >( fn), size, do_unwind, do_return, stack_allocator() ) )
+ {}
+
+ template< typename Fn, typename Allocator >
+ context( Fn & fn, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return, Allocator const& alloc) :
+ impl_( make_context_( static_cast< Fn & >( fn), size, do_unwind, do_return, alloc) )
+ {}
+
+ template< typename Fn >
+ context( Fn & fn, std::size_t size, flag_unwind_t do_unwind, context & nxt) :
+ impl_( make_context_( static_cast< Fn & >( fn), size, do_unwind, nxt, stack_allocator() ) )
+ {}
+
+ template< typename Fn, typename Allocator >
+ context( Fn & fn, std::size_t size, flag_unwind_t do_unwind, context & nxt, Allocator const& alloc) :
+ impl_( make_context_( static_cast< Fn & >( fn), size, do_unwind, nxt, alloc) )
+ {}
+# endif
+ template< typename Fn >
+ context( Fn && fn, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return) :
+ impl_( make_context_( static_cast< Fn && >( fn), size, do_unwind, do_return, stack_allocator() ) )
+ {}
+
+ template< typename Fn, typename Allocator >
+ context( Fn && fn, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return, Allocator const& alloc) :
+ impl_( make_context_( static_cast< Fn && >( fn), size, do_unwind, do_return, alloc) )
+ {}
+
+ template< typename Fn >
+ context( Fn && fn, std::size_t size, flag_unwind_t do_unwind, context & nxt) :
+ impl_( make_context_( static_cast< Fn && >( fn), size, do_unwind, nxt, stack_allocator() ) )
+ {}
+
+ template< typename Fn, typename Allocator >
+ context( Fn && fn, std::size_t size, flag_unwind_t do_unwind, context & nxt, Allocator const& alloc) :
+ impl_( make_context_( static_cast< Fn && >( fn), size, do_unwind, nxt, alloc) )
+ {}
+#else
+ template< typename Fn >
+ context( Fn fn, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return) :
+ impl_( make_context_( fn, size, do_unwind, do_return, stack_allocator() ) )
+ {}
+
+ template< typename Fn, typename Allocator >
+ context( Fn fn, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return, Allocator const& alloc) :
+ impl_( make_context_( fn, size, do_unwind, do_return, alloc) )
+ {}
+
+ template< typename Fn >
+ context( Fn fn, std::size_t size, flag_unwind_t do_unwind, context & nxt) :
+ impl_( make_context_( fn, size, do_unwind, nxt, stack_allocator() ) )
+ {}
+
+ template< typename Fn, typename Allocator >
+ context( Fn fn, std::size_t size, flag_unwind_t do_unwind, context & nxt, Allocator const& alloc) :
+ impl_( make_context_( fn, size, do_unwind, nxt, alloc) )
+ {}
+
+ template< typename Fn >
+ context( BOOST_RV_REF( Fn) fn, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return) :
+ impl_( make_context_( fn, size, do_unwind, do_return, stack_allocator() ) )
+ {}
+
+ template< typename Fn, typename Allocator >
+ context( BOOST_RV_REF( Fn) fn, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return, Allocator const& alloc) :
+ impl_( make_context_( fn, size, do_unwind, do_return, alloc) )
+ {}
+
+ template< typename Fn >
+ context( BOOST_RV_REF( Fn) fn, std::size_t size, flag_unwind_t do_unwind, context & nxt) :
+ impl_( make_context_( fn, size, do_unwind, nxt, stack_allocator() ) )
+ {}
+
+ template< typename Fn, typename Allocator >
+ context( BOOST_RV_REF( Fn) fn, std::size_t size, flag_unwind_t do_unwind, context & nxt, Allocator const& alloc) :
+ impl_( make_context_( fn, size, do_unwind, nxt, alloc) )
+ {}
+#endif
+
+#define BOOST_CONTEXT_ARG(z, n, unused) BOOST_PP_CAT(A, n) BOOST_PP_CAT(a, n)
+
+#define BOOST_CONTEXT_ARGS(n) BOOST_PP_ENUM(n, BOOST_CONTEXT_ARG, ~)
+
+#define BOOST_CONTEXT_CTOR(z, n, unused) \
+ template< typename Fn, BOOST_PP_ENUM_PARAMS(n, typename A) > \
+ context( Fn fn, BOOST_CONTEXT_ARGS(n), std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return) : \
+ impl_( \
+ make_context_( \
+ boost::bind( boost::type< void >(), fn, BOOST_PP_ENUM_PARAMS(n, a) ), \
+ size, do_unwind, do_return, stack_allocator() ) ) \
+ {} \
+ \
+ template< typename Fn, typename Allocator, BOOST_PP_ENUM_PARAMS(n, typename A) > \
+ context( Fn fn, BOOST_CONTEXT_ARGS(n), std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return, Allocator const& alloc) : \
+ impl_( \
+ make_context_( \
+ boost::bind( boost::type< void >(), fn, BOOST_PP_ENUM_PARAMS(n, a) ), \
+ size, do_unwind, do_return, alloc) ) \
+ {} \
+ \
+ template< typename Fn, BOOST_PP_ENUM_PARAMS(n, typename A) > \
+ context( Fn fn, BOOST_CONTEXT_ARGS(n), std::size_t size, flag_unwind_t do_unwind, context & nxt) : \
+ impl_( \
+ make_context_( \
+ boost::bind( boost::type< void >(), fn, BOOST_PP_ENUM_PARAMS(n, a) ), \
+ size, do_unwind, nxt, stack_allocator() ) ) \
+ {} \
+ \
+ template< typename Fn, typename Allocator, BOOST_PP_ENUM_PARAMS(n, typename A) > \
+ context( Fn fn, BOOST_CONTEXT_ARGS(n), std::size_t size, flag_unwind_t do_unwind, context & nxt, Allocator const& alloc) : \
+ impl_( \
+ make_context_( \
+ boost::bind( boost::type< void >(), fn, BOOST_PP_ENUM_PARAMS(n, a) ), \
+ size, do_unwind, nxt, alloc) ) \
+ {} \
+
+#ifndef BOOST_CONTEXT_ARITY
+#define BOOST_CONTEXT_ARITY 10
+#endif
+
+BOOST_PP_REPEAT_FROM_TO( 1, BOOST_CONTEXT_ARITY, BOOST_CONTEXT_CTOR, ~)
+
+#undef BOOST_CONTEXT_CTOR
+#undef BOOST_CONTEXT_ARGS
+#undef BOOST_CONTEXT_ARG
+
+ context( BOOST_RV_REF( context) other) :
+ impl_()
+ { swap( other); }
+
+ context & operator=( BOOST_RV_REF( context) other)
+ {
+ if ( this == & other) return * this;
+ context tmp( boost::move( other) );
+ swap( tmp);
+ return * this;
+ }
+
+ operator unspecified_bool_type() const
+ { return impl_ ? unspecified_bool : 0; }
+
+ bool operator!() const
+ { return ! impl_; }
+
+ void swap( context & other)
+ { impl_.swap( other.impl_); }
+
+ intptr_t start()
+ {
+ BOOST_ASSERT( impl_);
+ return impl_->start();
+ }
+
+ intptr_t resume( intptr_t vp = 0)
+ {
+ BOOST_ASSERT( impl_);
+ return impl_->resume( vp);
+ }
+
+ intptr_t suspend( intptr_t vp = 0)
+ {
+ BOOST_ASSERT( impl_);
+ return impl_->suspend( vp);
+ }
+
+ void unwind_stack()
+ {
+ BOOST_ASSERT( impl_);
+ impl_->unwind_stack();
+ }
+
+ bool is_complete() const
+ {
+ BOOST_ASSERT( impl_);
+ return impl_->is_complete();
+ }
+};
+
+inline
+void swap( context & l, context & r)
+{ l.swap( r); }
+
+}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXTS_CONTEXT_H

Added: trunk/boost/context/detail/config.hpp
==============================================================================
--- (empty file)
+++ trunk/boost/context/detail/config.hpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,42 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_CONTEXTS_DETAIL_CONFIG_H
+#define BOOST_CONTEXTS_DETAIL_CONFIG_H
+
+#include <boost/config.hpp>
+#include <boost/detail/workaround.hpp>
+
+#ifdef BOOST_CONTEXT_DECL
+# undef BOOST_CONTEXT_DECL
+#endif
+
+#if defined(BOOST_HAS_DECLSPEC)
+# if defined(BOOST_ALL_DYN_LINK) || defined(BOOST_CONTEXT_DYN_LINK)
+# if ! defined(BOOST_DYN_LINK)
+# define BOOST_DYN_LINK
+# endif
+# if defined(BOOST_CONTEXT_SOURCE)
+# define BOOST_CONTEXT_DECL BOOST_SYMBOL_EXPORT
+# else
+# define BOOST_CONTEXT_DECL BOOST_SYMBOL_IMPORT
+# endif
+# endif
+#endif
+
+#if ! defined(BOOST_CONTEXT_DECL)
+# define BOOST_CONTEXT_DECL
+#endif
+
+#if ! defined(BOOST_CONTEXT_SOURCE) && ! defined(BOOST_ALL_NO_LIB) && ! defined(BOOST_CONTEXT_NO_LIB)
+# define BOOST_LIB_NAME boost_context
+# if defined(BOOST_ALL_DYN_LINK) || defined(BOOST_CONTEXT_DYN_LINK)
+# define BOOST_DYN_LINK
+# endif
+# include <boost/config/auto_link.hpp>
+#endif
+
+#endif // BOOST_CONTEXTS_DETAIL_CONFIG_H

Added: trunk/boost/context/detail/context_base.hpp
==============================================================================
--- (empty file)
+++ trunk/boost/context/detail/context_base.hpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,229 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_CONTEXTS_DETAIL_CONTEXT_BASE_H
+#define BOOST_CONTEXTS_DETAIL_CONTEXT_BASE_H
+
+#include <algorithm>
+#include <cstddef>
+#include <cstdlib>
+#include <cstring>
+
+#include <boost/assert.hpp>
+#include <boost/config.hpp>
+#include <boost/cstdint.hpp>
+#include <boost/intrusive_ptr.hpp>
+#include <boost/utility.hpp>
+
+#include <boost/context/detail/config.hpp>
+#include <boost/context/fcontext.hpp>
+#include <boost/context/flags.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace contexts {
+namespace detail {
+
+struct forced_unwind {};
+
+template< typename Ctx >
+void trampoline( intptr_t vp)
+{
+ BOOST_ASSERT( vp);
+
+ Ctx * ctx( reinterpret_cast< Ctx * >( vp) );
+
+ try
+ { ctx->exec(); }
+ catch ( forced_unwind const&)
+ {
+ ctx->flags_ |= Ctx::flag_complete;
+ boost_fcontext_jump( & ctx->ctx_callee_, & ctx->ctx_caller_, 0);
+ }
+ catch (...)
+ { std::terminate(); }
+
+ ctx->flags_ |= Ctx::flag_complete;
+
+ // in order to return to the code invoked the context
+ // nxt_->caller_ hast to set to the first one
+ if ( ctx->nxt_)
+ {
+ Ctx * nxt( dynamic_cast< Ctx * >( ctx->nxt_.get() ) );
+ BOOST_ASSERT( nxt);
+ std::swap( nxt->ctx_caller_, ctx->ctx_caller_);
+ if ( 0 != ( nxt->flags_ & Ctx::flag_do_return) )
+ nxt->ctx_callee_.fc_link = & nxt->ctx_caller_;
+ nxt->flags_ |= Ctx::flag_running;
+ nxt->flags_ |= Ctx::flag_started;
+ }
+}
+
+class context_base : private noncopyable
+{
+public:
+ typedef intrusive_ptr< context_base > ptr_t;
+
+ template< typename Allocator >
+ context_base(
+ Allocator & alloc, std::size_t size,
+ flag_unwind_t do_unwind, flag_return_t do_return) :
+ use_count_( 0), base_( alloc.allocate( size) ), ctx_caller_(), ctx_callee_(), nxt_(),
+ flags_( stack_unwind == do_unwind ? flag_force_unwind : flag_dont_force_unwind)
+ {
+ BOOST_ASSERT( base_);
+
+ std::memset( & ctx_caller_, 0, sizeof( ctx_caller_) );
+ std::memset( & ctx_callee_, 0, sizeof( ctx_callee_) );
+ ctx_callee_.fc_stack.ss_base = base_;
+ ctx_callee_.fc_stack.ss_limit =
+ static_cast< char * >( ctx_callee_.fc_stack.ss_base) - size;
+
+ if ( return_to_caller == do_return)
+ {
+ flags_ |= flag_do_return;
+ ctx_callee_.fc_link = & ctx_caller_;
+ }
+
+ boost_fcontext_make(
+ & ctx_callee_, trampoline< context_base >, reinterpret_cast< intptr_t >( this) );
+ }
+
+ template< typename Allocator >
+ context_base( Allocator & alloc, std::size_t size, flag_unwind_t do_unwind, ptr_t nxt) :
+ use_count_( 0), base_( alloc.allocate( size) ), ctx_caller_(), ctx_callee_(), nxt_( nxt),
+ flags_( stack_unwind == do_unwind ? flag_force_unwind : flag_dont_force_unwind)
+ {
+ BOOST_ASSERT( base_);
+ BOOST_ASSERT( ! nxt_->is_complete() );
+
+ std::memset( & ctx_callee_, 0, sizeof( ctx_callee_) );
+ std::memset( & ctx_caller_, 0, sizeof( ctx_caller_) );
+ ctx_callee_.fc_stack.ss_base = base_;
+ ctx_callee_.fc_stack.ss_limit =
+ static_cast< char * >( ctx_callee_.fc_stack.ss_base) - size;
+ ctx_callee_.fc_link = & dynamic_pointer_cast< context_base >( nxt_)->ctx_callee_;
+
+ boost_fcontext_make(
+ & ctx_callee_, trampoline< context_base >, reinterpret_cast< intptr_t >( this) );
+ }
+
+ virtual ~context_base() {}
+
+ template< typename Allocator >
+ void cleanup( Allocator & alloc)
+ {
+ if ( ! is_complete()
+ && ( is_started() || is_resumed() )
+ && ( unwind_requested() ) )
+ unwind_stack();
+ std::size_t size = static_cast< char * >( ctx_callee_.fc_stack.ss_base) -
+ static_cast< char * >( ctx_callee_.fc_stack.ss_limit);
+ alloc.deallocate( base_, size);
+ }
+
+ bool unwind_requested() const
+ { return 0 != ( flags_ & flag_force_unwind); }
+
+ bool is_complete() const
+ { return 0 != ( flags_ & flag_complete); }
+
+ bool is_started() const
+ { return 0 != ( flags_ & flag_started); }
+
+ bool is_resumed() const
+ { return 0 != ( flags_ & flag_started); }
+
+ bool is_running() const
+ { return 0 != ( flags_ & flag_running); }
+
+ intptr_t start()
+ {
+ BOOST_ASSERT( ! is_complete() );
+ BOOST_ASSERT( ! is_started() );
+ BOOST_ASSERT( ! is_running() );
+
+ flags_ |= flag_started;
+ flags_ |= flag_running;
+ return boost_fcontext_start( & ctx_caller_, & ctx_callee_);
+ }
+
+ intptr_t resume( intptr_t vp)
+ {
+ BOOST_ASSERT( is_started() );
+ BOOST_ASSERT( ! is_complete() );
+ BOOST_ASSERT( ! is_running() );
+
+ flags_ |= flag_resumed;
+ flags_ |= flag_running;
+ return boost_fcontext_jump( & ctx_caller_, & ctx_callee_, vp);
+ }
+
+ intptr_t suspend( intptr_t vp)
+ {
+ BOOST_ASSERT( ! is_complete() );
+ BOOST_ASSERT( is_running() );
+
+ flags_ &= ~flag_running;
+ intptr_t res = boost_fcontext_jump( & ctx_callee_, & ctx_caller_, vp);
+ if ( 0 != ( flags_ & flag_unwind_stack) )
+ throw forced_unwind();
+ return res;
+ }
+
+ void unwind_stack()
+ {
+ BOOST_ASSERT( ! is_complete() );
+ BOOST_ASSERT( ! is_running() );
+
+ flags_ |= flag_unwind_stack;
+ boost_fcontext_jump( & ctx_caller_, & ctx_callee_, 0);
+ flags_ &= ~flag_unwind_stack;
+ BOOST_ASSERT( is_complete() );
+ }
+
+ virtual void exec() = 0;
+
+ friend inline void intrusive_ptr_add_ref( context_base * p)
+ { ++p->use_count_; }
+
+ friend inline void intrusive_ptr_release( context_base * p)
+ { if ( --p->use_count_ == 0) delete p; }
+
+private:
+ template< typename T >
+ friend void trampoline( intptr_t vp);
+
+ enum flag_t
+ {
+ flag_started = 1 << 1,
+ flag_resumed = 1 << 2,
+ flag_running = 1 << 3,
+ flag_complete = 1 << 4,
+ flag_unwind_stack = 1 << 5,
+ flag_force_unwind = 1 << 6,
+ flag_dont_force_unwind = 1 << 7,
+ flag_do_return = 1 << 8,
+ };
+
+ std::size_t use_count_;
+ void * base_;
+ boost_fcontext_t ctx_caller_;
+ boost_fcontext_t ctx_callee_;
+ ptr_t nxt_;
+ short flags_;
+};
+
+}}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXTS_DETAIL_CONTEXT_BASE_H

Added: trunk/boost/context/detail/context_object.hpp
==============================================================================
--- (empty file)
+++ trunk/boost/context/detail/context_object.hpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,158 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_CONTEXTS_DETAIL_CONTEXT_OBJECT_H
+#define BOOST_CONTEXTS_DETAIL_CONTEXT_OBJECT_H
+
+#include <cstddef>
+
+#include <boost/assert.hpp>
+#include <boost/config.hpp>
+#include <boost/move/move.hpp>
+#include <boost/type_traits/remove_reference.hpp>
+#include <boost/utility/base_from_member.hpp>
+
+#include <boost/context/detail/config.hpp>
+#include <boost/context/detail/context_base.hpp>
+#include <boost/context/flags.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace contexts {
+namespace detail {
+
+template< typename Fn, typename Allocator >
+class context_object : private base_from_member< Fn >,
+ private base_from_member< Allocator >,
+ public context_base
+{
+private:
+ typedef base_from_member< Fn > fn_t;
+ typedef base_from_member< Allocator > alloc_t;
+
+ context_object( context_object &);
+ context_object & operator=( context_object const&);
+
+public:
+#ifndef BOOST_NO_RVALUE_REFERENCES
+ context_object( Fn & fn, Allocator const& alloc, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return) :
+ fn_t( fn), alloc_t( alloc),
+ context_base( alloc_t::member, size, do_unwind, do_return)
+ {}
+
+ context_object( Fn & fn, Allocator const& alloc, std::size_t size, flag_unwind_t do_unwind, typename context_base::ptr_t nxt) :
+ fn_t( fn), alloc_t( alloc),
+ context_base( alloc_t::member, size, do_unwind, nxt)
+ {}
+
+ context_object( Fn && fn, Allocator const& alloc, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return) :
+ fn_t( static_cast< Fn && >( fn) ), alloc_t( alloc),
+ context_base( alloc_t::member, size, do_unwind, do_return)
+ {}
+
+ context_object( Fn && fn, Allocator const& alloc, std::size_t size, flag_unwind_t do_unwind, typename context_base::ptr_t nxt) :
+ fn_t( static_cast< Fn && >( fn) ), alloc_t( alloc),
+ context_base( alloc_t::member, size, do_unwind, nxt)
+ {}
+#else
+ context_object( Fn fn, Allocator const& alloc, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return) :
+ fn_t( fn), alloc_t( alloc),
+ context_base( alloc_t::member, size, do_unwind, do_return)
+ {}
+
+ context_object( Fn fn, Allocator const& alloc, std::size_t size, flag_unwind_t do_unwind, typename context_base::ptr_t nxt) :
+ fn_t( fn), alloc_t( alloc),
+ context_base( alloc_t::member, size, do_unwind, nxt)
+ {}
+
+ context_object( BOOST_RV_REF( Fn) fn, Allocator const& alloc, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return) :
+ fn_t( fn), alloc_t( alloc),
+ context_base( alloc_t::member, size, do_unwind, do_return)
+ {}
+
+ context_object( BOOST_RV_REF( Fn) fn, Allocator const& alloc, std::size_t size, flag_unwind_t do_unwind, typename context_base::ptr_t nxt) :
+ fn_t( fn), alloc_t( alloc),
+ context_base( alloc_t::member, size, do_unwind, nxt)
+ {}
+#endif
+
+ ~context_object()
+ { cleanup( alloc_t::member); }
+
+ void exec()
+ { fn_t::member(); }
+};
+
+template< typename Fn, typename Allocator >
+class context_object< reference_wrapper< Fn >, Allocator > : private base_from_member< Fn & >,
+ private base_from_member< Allocator >,
+ public context_base
+{
+private:
+ typedef base_from_member< Fn & > fn_t;
+ typedef base_from_member< Allocator > alloc_t;
+
+ context_object( context_object &);
+ context_object & operator=( context_object const&);
+
+public:
+ context_object( reference_wrapper< Fn > fn, Allocator const& alloc, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return) :
+ fn_t( fn), alloc_t( alloc),
+ context_base( alloc_t::member, size, do_unwind, do_return)
+ {}
+
+ context_object( reference_wrapper< Fn > fn, Allocator const& alloc, std::size_t size, flag_unwind_t do_unwind, typename context_base::ptr_t nxt) :
+ fn_t( fn), alloc_t( alloc),
+ context_base( alloc_t::member, size, do_unwind, nxt)
+ {}
+
+ ~context_object()
+ { cleanup( alloc_t::member); }
+
+ void exec()
+ { fn_t::member(); }
+};
+
+template< typename Fn, typename Allocator >
+class context_object< const reference_wrapper< Fn >, Allocator > : private base_from_member< Fn & >,
+ private base_from_member< Allocator >,
+ public context_base
+{
+private:
+ typedef base_from_member< Fn & > fn_t;
+ typedef base_from_member< Allocator > alloc_t;
+
+ context_object( context_object &);
+ context_object & operator=( context_object const&);
+
+public:
+ context_object( const reference_wrapper< Fn > fn, Allocator const& alloc, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return) :
+ fn_t( fn), alloc_t( alloc),
+ context_base( alloc_t::member, size, do_unwind, do_return)
+ {}
+
+ context_object( const reference_wrapper< Fn > fn, Allocator const& alloc, std::size_t size, flag_unwind_t do_unwind, typename context_base::ptr_t nxt) :
+ fn_t( fn), alloc_t( alloc),
+ context_base( alloc_t::member, size, do_unwind, nxt)
+ {}
+
+ ~context_object()
+ { cleanup( alloc_t::member); }
+
+ void exec()
+ { fn_t::member(); }
+};
+
+}}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXTS_DETAIL_CONTEXT_OBJECT_H

Added: trunk/boost/context/detail/fcontext_arm.hpp
==============================================================================
--- (empty file)
+++ trunk/boost/context/detail/fcontext_arm.hpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,45 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_CONTEXTS_DETAIL_FCONTEXT_ARM_H
+#define BOOST_CONTEXTS_DETAIL_FCONTEXT_ARM_H
+
+#include <boost/config.hpp>
+#include <boost/cstdint.hpp>
+
+#include <boost/context/detail/config.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+extern "C" {
+
+#define BOOST_CONTEXT_CALLDECL
+
+typedef struct boost_fcontext_stack boost_fcontext_stack_t;
+struct boost_fcontext_stack
+{
+ void * ss_base;
+ void * ss_limit;
+};
+
+typedef struct boost_fcontext boost_fcontext_t;
+struct boost_fcontext
+{
+ boost::uint32_t fc_greg[11];
+ boost::uint32_t fc_freg[16];
+ boost_fcontext_stack_t fc_stack;
+ boost_fcontext_t * fc_link;
+};
+
+}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXTS_DETAIL_FCONTEXT_ARM_H

Added: trunk/boost/context/detail/fcontext_i386.hpp
==============================================================================
--- (empty file)
+++ trunk/boost/context/detail/fcontext_i386.hpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,45 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_CONTEXTS_DETAIL_FCONTEXT_I386H
+#define BOOST_CONTEXTS_DETAIL_FCONTEXT_I386H
+
+#include <boost/config.hpp>
+#include <boost/cstdint.hpp>
+
+#include <boost/context/detail/config.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+extern "C" {
+
+#define BOOST_CONTEXT_CALLDECL __attribute__((cdecl))
+
+typedef struct boost_fcontext_stack boost_fcontext_stack_t;
+struct boost_fcontext_stack
+{
+ void * ss_base;
+ void * ss_limit;
+};
+
+typedef struct boost_fcontext boost_fcontext_t;
+struct boost_fcontext
+{
+ boost::uint32_t fc_greg[6];
+ boost::uint32_t fc_freg[2];
+ boost_fcontext_stack_t fc_stack;
+ boost_fcontext_t * fc_link;
+};
+
+}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXTS_DETAIL_FCONTEXT_I386_H

Added: trunk/boost/context/detail/fcontext_i386_win.hpp
==============================================================================
--- (empty file)
+++ trunk/boost/context/detail/fcontext_i386_win.hpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,47 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_CONTEXTS_DETAIL_FCONTEXT_I386H
+#define BOOST_CONTEXTS_DETAIL_FCONTEXT_I386H
+
+#include <boost/config.hpp>
+#include <boost/cstdint.hpp>
+
+#include <boost/context/detail/config.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+extern "C" {
+
+#define BOOST_CONTEXT_CALLDECL __cdecl
+
+typedef struct boost_fcontext_stack boost_fcontext_stack_t;
+struct boost_fcontext_stack
+{
+ void * ss_base;
+ void * ss_limit;
+};
+
+typedef struct boost_fcontext boost_fcontext_t;
+struct boost_fcontext
+{
+ boost::uint32_t fc_greg[6];
+ boost::uint32_t fc_freg[2];
+ boost_fcontext_stack_t fc_stack;
+ boost_fcontext_t * fc_link;
+ void * fc_excpt_lst;
+ void * fc_local_storage;
+};
+
+}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXTS_DETAIL_FCONTEXT_I386_H

Added: trunk/boost/context/detail/fcontext_mips.hpp
==============================================================================
--- (empty file)
+++ trunk/boost/context/detail/fcontext_mips.hpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,51 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_CONTEXTS_DETAIL_FCONTEXT_MIPS_H
+#define BOOST_CONTEXTS_DETAIL_FCONTEXT_MIPS_H
+
+#include <boost/config.hpp>
+#include <boost/cstdint.hpp>
+
+#include <boost/context/detail/config.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+extern "C" {
+
+#define BOOST_CONTEXT_CALLDECL
+
+// on MIPS we assume 64bit regsiters - even for 32bit ABIs
+
+typedef struct boost_fcontext_stack boost_fcontext_stack_t;
+struct boost_fcontext_stack
+{
+ void * ss_base;
+ void * ss_limit;
+};
+
+typedef struct boost_fcontext boost_fcontext_t;
+struct boost_fcontext
+{
+ boost::uint64_t fc_greg[13];
+# if _MIPS_SIM == _ABI64
+ boost::uint64_t fc_freg[8];
+# else
+ boost::uint64_t fc_freg[6];
+# endif
+ boost_fcontext_stack_t fc_stack;
+ boost_fcontext_t * fc_link;
+};
+
+}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXTS_DETAIL_FCONTEXT_MIPS_H

Added: trunk/boost/context/detail/fcontext_ppc.hpp
==============================================================================
--- (empty file)
+++ trunk/boost/context/detail/fcontext_ppc.hpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,49 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_CONTEXTS_DETAIL_FCONTEXT_PPC_H
+#define BOOST_CONTEXTS_DETAIL_FCONTEXT_PPC_H
+
+#include <boost/config.hpp>
+#include <boost/cstdint.hpp>
+
+#include <boost/context/detail/config.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+extern "C" {
+
+#define BOOST_CONTEXT_CALLDECL
+
+typedef struct boost_fcontext_stack boost_fcontext_stack_t;
+struct boost_fcontext_stack
+{
+ void * ss_base;
+ void * ss_limit;
+};
+
+typedef struct boost_fcontext boost_fcontext_t;
+struct boost_fcontext
+{
+# if defined(__powerpc64__)
+ boost::uint64_t fc_greg[23];
+# else
+ boost::uint32_t fc_greg[23];
+# endif
+ boost::uint64_t fc_freg[19];
+ boost_fcontext_stack_t fc_stack;
+ boost_fcontext_t * fc_link;
+};
+
+}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXTS_DETAIL_FCONTEXT_PPC_H

Added: trunk/boost/context/detail/fcontext_x86_64.hpp
==============================================================================
--- (empty file)
+++ trunk/boost/context/detail/fcontext_x86_64.hpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,45 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_CONTEXTS_DETAIL_FCONTEXT_X86_64_H
+#define BOOST_CONTEXTS_DETAIL_FCONTEXT_X86_64_H
+
+#include <boost/config.hpp>
+#include <boost/cstdint.hpp>
+
+#include <boost/context/detail/config.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+extern "C" {
+
+#define BOOST_CONTEXT_CALLDECL
+
+typedef struct boost_fcontext_stack boost_fcontext_stack_t;
+struct boost_fcontext_stack
+{
+ void * ss_base;
+ void * ss_limit;
+};
+
+typedef struct boost_fcontext boost_fcontext_t;
+struct boost_fcontext
+{
+ boost::uint64_t fc_greg[8];
+ boost::uint32_t fc_freg[2];
+ boost_fcontext_stack_t fc_stack;
+ boost_fcontext_t * fc_link;
+};
+
+}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXTS_DETAIL_FCONTEXT_X86_64_H

Added: trunk/boost/context/detail/fcontext_x86_64_win.hpp
==============================================================================
--- (empty file)
+++ trunk/boost/context/detail/fcontext_x86_64_win.hpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,47 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_CONTEXTS_DETAIL_FCONTEXT_X86_64_H
+#define BOOST_CONTEXTS_DETAIL_FCONTEXT_X86_64_H
+
+#include <boost/assert.hpp>
+#include <boost/config.hpp>
+#include <boost/cstdint.hpp>
+
+#include <boost/context/detail/config.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+extern "C" {
+
+#define BOOST_CONTEXT_CALLDECL
+
+typedef struct boost_fcontext_stack boost_fcontext_stack_t;
+struct boost_fcontext_stack
+{
+ void * ss_base;
+ void * ss_limit;
+};
+
+typedef struct boost_fcontext boost_fcontext_t;
+struct boost_fcontext
+{
+ boost::uint64_t fc_greg[10];
+ boost::uint32_t fc_freg[2];
+ boost_fcontext_stack_t fc_stack;
+ boost_fcontext_t * fc_link;
+ void * fc_local_storage;
+};
+
+}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXTS_DETAIL_FCONTEXT_X86_64_H

Added: trunk/boost/context/fcontext.hpp
==============================================================================
--- (empty file)
+++ trunk/boost/context/fcontext.hpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,62 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_CONTEXTS_FCONTEXT_H
+#define BOOST_CONTEXTS_FCONTEXT_H
+
+#include <boost/config.hpp>
+#include <boost/cstdint.hpp>
+
+#include <boost/context/detail/config.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+// Windows
+#if defined(BOOST_WINDOWS)
+// i386
+# if defined(_WIN32) && ! defined(_WIN64)
+# include <boost/context/detail/fcontext_i386_win.hpp>
+// x86_64
+# elif defined(_WIN32) && defined(_WIN64)
+# include <boost/context/detail/fcontext_x86_64_win.hpp>
+# else
+# error "platform not supported"
+# endif
+// POSIX
+#else
+// i386
+# if defined(__i386__)
+# include <boost/context/detail/fcontext_i386.hpp>
+// x86_64
+# elif defined(__x86_64__)
+# include <boost/context/detail/fcontext_x86_64.hpp>
+// arm
+# elif defined(__arm__)
+# include <boost/context/detail/fcontext_arm.hpp>
+// mips
+# elif defined(__mips__)
+# include <boost/context/detail/fcontext_mips.hpp>
+// powerpc
+# elif defined(__powerpc__)
+# include <boost/context/detail/fcontext_ppc.hpp>
+# else
+# error "platform not supported"
+# endif
+#endif
+
+extern "C" BOOST_CONTEXT_DECL void * BOOST_CONTEXT_CALLDECL boost_fcontext_align( void * vp);
+extern "C" BOOST_CONTEXT_DECL intptr_t BOOST_CONTEXT_CALLDECL boost_fcontext_start( boost_fcontext_t * ofc, boost_fcontext_t const* nfc);
+extern "C" BOOST_CONTEXT_DECL intptr_t BOOST_CONTEXT_CALLDECL boost_fcontext_jump( boost_fcontext_t * ofc, boost_fcontext_t const* nfc, intptr_t vp);
+extern "C" BOOST_CONTEXT_DECL void BOOST_CONTEXT_CALLDECL boost_fcontext_make( boost_fcontext_t * fc, void (* fn)( intptr_t), intptr_t vp);
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXTS_FCONTEXT_H
+

Added: trunk/boost/context/flags.hpp
==============================================================================
--- (empty file)
+++ trunk/boost/context/flags.hpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,27 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_CONTEXTS_FLAGS_H
+#define BOOST_CONTEXTS_FLAGS_H
+
+namespace boost {
+namespace contexts {
+
+enum flag_unwind_t
+{
+ stack_unwind = 0,
+ no_stack_unwind
+};
+
+enum flag_return_t
+{
+ return_to_caller = 0,
+ exit_application
+};
+
+}}
+
+#endif // BOOST_CONTEXTS_FLAGS_H

Added: trunk/boost/context/stack_allocator.hpp
==============================================================================
--- (empty file)
+++ trunk/boost/context/stack_allocator.hpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,37 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_CONTEXTS_STACK_ALLOCATOR_H
+#define BOOST_CONTEXTS_STACK_ALLOCATOR_H
+
+#include <cstddef>
+
+#include <boost/config.hpp>
+
+#include <boost/context/detail/config.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace contexts {
+
+class BOOST_CONTEXT_DECL stack_allocator
+{
+public:
+ void * allocate( std::size_t) const;
+
+ void deallocate( void *, std::size_t) const;
+};
+
+}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXTS_STACK_ALLOCATOR_H

Added: trunk/boost/context/stack_utils.hpp
==============================================================================
--- (empty file)
+++ trunk/boost/context/stack_utils.hpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,41 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_CONTEXTS_STACK_UTILS_H
+#define BOOST_CONTEXTS_STACK_UTILS_H
+
+#include <cstddef>
+
+#include <boost/config.hpp>
+
+#include <boost/context/detail/config.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace contexts {
+
+BOOST_CONTEXT_DECL std::size_t default_stacksize();
+
+BOOST_CONTEXT_DECL std::size_t minimum_stacksize();
+
+BOOST_CONTEXT_DECL std::size_t maximum_stacksize();
+
+BOOST_CONTEXT_DECL std::size_t pagesize();
+
+BOOST_CONTEXT_DECL std::size_t page_count( std::size_t stacksize);
+
+BOOST_CONTEXT_DECL bool is_stack_unbound();
+
+}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif
+
+#endif // BOOST_CONTEXTS_STACK_UTILS_H

Added: trunk/libs/context/build/Jamfile.v2
==============================================================================
--- (empty file)
+++ trunk/libs/context/build/Jamfile.v2 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,225 @@
+
+# Boost.Context Library Build Jamfile
+
+# Copyright Oliver Kowalke 2009.
+# Distributed under the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE_1_0.txt or copy at
+# http://www.boost.org/LICENSE_1_0.txt)
+
+import common ;
+import feature ;
+import indirect ;
+import modules ;
+import os ;
+import toolset ;
+
+project boost/context
+ : source-location ../src
+ : usage-requirements
+ <link>shared:<define>BOOST_CONTEXT_DYN_LINK=1
+ ;
+
+local rule default_binary_format ( )
+{
+ local tmp = elf ;
+ if [ os.name ] = "MACOSX" { tmp = mach-o ; }
+ if [ os.name ] = "NT" { tmp = pe ; }
+ return $(tmp) ;
+}
+
+feature.feature binary-format
+ : elf
+ mach-o
+ pe
+ : propagated
+ ;
+feature.set-default binary-format : [ default_binary_format ] ;
+
+
+local rule default_abi ( )
+{
+ local tmp = sysv ;
+ if [ os.name ] = "NT" { tmp = ms ; }
+ else if [ os.platform ] = "ARM" { tmp = aapcs ; }
+ else if [ os.platform ] = "MIPS" { tmp = o32 ; }
+ return $(tmp) ;
+}
+
+feature.feature abi
+ : aapcs
+ eabi
+ ms
+ n32
+ n64
+ o32
+ o64
+ sysv
+ : propagated
+ ;
+feature.set-default abi : [ default_abi ] ;
+
+
+alias asm_context_sources
+ : stack_allocator_posix.cpp
+ asm/fcontext_arm_aapcs_elf_gas.S
+ stack_utils_posix.cpp
+ : <abi>aapcs
+ <architecture>arm
+ <binary-format>elf
+ ;
+
+alias asm_context_sources
+ : stack_allocator_posix.cpp
+ asm/fcontext_mips32_o32_elf_gas.S
+ stack_utils_posix.cpp
+ : <abi>o32
+ <architecture>mips1
+ <binary-format>elf
+ ;
+
+#alias asm_context_sources
+# : stack_allocator_posix.cpp
+# asm/fcontext_mips64_n32_elf_gas.S
+# stack_utils_posix.cpp
+# : <abi>n32
+# <architecture>mips1
+# <binary-format>elf
+# ;
+#
+#alias asm_context_sources
+# : stack_allocator_posix.cpp
+# asm/fcontext_mips64_n64_elf_gas.S
+# stack_utils_posix.cpp
+# : <abi>n64
+# <architecture>mips1
+# <binary-format>elf
+# ;
+#
+#alias asm_context_sources
+# : stack_allocator_posix.cpp
+# asm/fcontext_mips64_o64_elf_gas.S
+# stack_utils_posix.cpp
+# : <abi>o64
+# <architecture>mips1
+# <binary-format>elf
+# ;
+
+alias asm_context_sources
+ : stack_allocator_posix.cpp
+ asm/fcontext_ppc32_eabi_elf_gas.S
+ stack_utils_posix.cpp
+ : <abi>eabi
+ <address-model>32
+ <architecture>power
+ <binary-format>elf
+ ;
+
+alias asm_context_sources
+ : stack_allocator_posix.cpp
+ asm/fcontext_ppc32_sysv_elf_gas.S
+ stack_utils_posix.cpp
+ : <abi>sysv
+ <address-model>32
+ <architecture>power
+ <binary-format>elf
+ ;
+
+alias asm_context_sources
+ : stack_allocator_posix.cpp
+ asm/fcontext_ppc64_eabi_elf_gas.S
+ stack_utils_posix.cpp
+ : <abi>eabi
+ <address-model>64
+ <architecture>power
+ <binary-format>elf
+ ;
+
+alias asm_context_sources
+ : stack_allocator_posix.cpp
+ asm/fcontext_ppc64_sysv_elf_gas.S
+ stack_utils_posix.cpp
+ : <abi>sysv
+ <address-model>64
+ <architecture>power
+ <binary-format>elf
+ ;
+
+alias asm_context_sources
+ : stack_allocator_posix.cpp
+ asm/fcontext_i386_sysv_elf_gas.S
+ stack_utils_posix.cpp
+ : <abi>sysv
+ <address-model>32
+ <architecture>x86
+ <binary-format>elf
+ ;
+
+alias asm_context_sources
+ : stack_allocator_posix.cpp
+ asm/fcontext_x86_64_sysv_elf_gas.S
+ stack_utils_posix.cpp
+ : <abi>sysv
+ <address-model>64
+ <architecture>x86
+ <binary-format>elf
+ ;
+
+alias asm_context_sources
+ : stack_allocator_posix.cpp
+ asm/fcontext_x86_64_sysv_macho_gas.S
+ stack_utils_posix.cpp
+ : <abi>sysv
+ <address-model>64
+ <architecture>x86
+ <binary-format>mach-o
+ <target-os>darwin
+ ;
+
+alias asm_context_sources
+ : stack_allocator_windows.cpp
+ asm/fcontext_i386_ms_pe_masm.asm
+ stack_utils_windows.cpp
+ : <abi>ms
+ <address-model>32
+ <architecture>x86
+ <binary-format>pe
+ <target-os>windows
+ ;
+
+alias asm_context_sources
+ : stack_allocator_windows.cpp
+ asm/fcontext_x86_64_ms_pe_masm.asm
+ stack_utils_windows.cpp
+ : <abi>ms
+ <address-model>64
+ <architecture>x86
+ <binary-format>pe
+ <target-os>windows
+ ;
+
+explicit asm_context_sources ;
+
+
+alias context_sources
+ : stack_allocator_windows.cpp
+ stack_utils_windows.cpp
+ seh.cpp
+ : <target-os>windows
+ ;
+
+alias context_sources
+ : stack_allocator_posix.cpp
+ stack_utils_posix.cpp
+ ;
+
+explicit context_sources ;
+
+
+lib boost_context
+ : asm_context_sources
+ context_sources
+ fcontext.cpp
+ : <link>shared:<define>BOOST_CONTEXT_DYN_LINK=1
+ ;
+
+boost-install boost_context ;

Added: trunk/libs/context/doc/Jamfile.v2
==============================================================================
--- (empty file)
+++ trunk/libs/context/doc/Jamfile.v2 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,33 @@
+# (C) Copyright 2008 Anthony Williams
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+path-constant boost-images : ../../../doc/src/images ;
+
+xml context : context.qbk ;
+
+boostbook standalone
+ :
+ context
+ :
+ # HTML options first:
+ # Use graphics not text for navigation:
+ <xsl:param>navig.graphics=1
+ # How far down we chunk nested sections, basically all of them:
+ <xsl:param>chunk.section.depth=3
+ # Don't put the first section on the same page as the TOC:
+ <xsl:param>chunk.first.sections=1
+ # How far down sections get TOC's
+ <xsl:param>toc.section.depth=10
+ # Max depth in each TOC:
+ <xsl:param>toc.max.depth=3
+ # How far down we go with TOC's
+ <xsl:param>generate.section.toc.level=10
+ # Path for links to Boost:
+ <xsl:param>boost.root=../../../..
+ # Path for libraries index:
+ <xsl:param>boost.libraries=../../../../libs/libraries.htm
+ # Use the main Boost stylesheet:
+ <xsl:param>html.stylesheet=../../../../doc/html/boostbook.css
+ ;

Added: trunk/libs/context/doc/acknowledgements.qbk
==============================================================================
--- (empty file)
+++ trunk/libs/context/doc/acknowledgements.qbk 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,15 @@
+[/
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt
+]
+
+[section:acknowledgements Acknowledgments]
+
+I'd like to thank Adreas Fett, Artyom Beilis, Fernando Pelliccioni,
+Giovanni Piero Deretta, Gordon Woodhull, Helge Bahmann, Holger Grund,
+Jeffrey Lee Hellrung (Jr.), Keith Jeffery, Phil Endecott, Robert Stewart,
+Vicente J. Botet Escriba.
+
+[endsect]

Added: trunk/libs/context/doc/asio.qbk
==============================================================================
--- (empty file)
+++ trunk/libs/context/doc/asio.qbk 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,168 @@
+[/
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt
+]
+
+[section:asio ASIO]
+
+Adapted from [@http://blog.think-async.com/2009/08/secret-sauce-revealed.html
+Thinking Asynchronously in C++] using boost.asio to implement a simple echo
+server.
+
+Chris Kohlhoff uses stackless coroutines based on preprocessor-based switch
+statements to implement an echo server using boost.asio.
+Class `continuation` provides a simple coroutine implemenatation using
+boost.context.
+
+ class continuation
+ {
+ private:
+ boost::contexts::context ctx_;
+ boost::function< void( continuation &) > fn_;
+ bool started_;
+
+ void trampoline_()
+ { fn_( * this); }
+
+ public:
+ continuation( boost::function< void( continuation &) > const& fn) :
+ ctx_(
+ & continuation::trampoline_, this,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind, boost::contexts::return_to_caller),
+ fn_( fn), started_( false)
+ {}
+
+ void resume()
+ {
+ if ( ! started_)
+ {
+ started_ = true;
+ ctx_.start();
+ }
+ else ctx_.resume();
+ }
+
+ void suspend()
+ { ctx_.suspend(); }
+
+ bool is_complete() const
+ { return ctx_.is_complete(); }
+ };
+
+The operator `server::operator()` is called by the asio reactor and jumps to
+coroutine (which is entering or resuming in function `server::do_()`).
+In function `sever::do_()` the control flow is all in one place and easy to
+follow; *this is queued for accepting a connection before control flow
+is passed back to the reactor via `suspend()`. If `server::do_()` is reentered,
+a local buffer is created and an asynch. read operation is queued into the
+reactor.
+The control flow is then returned to the reactor for io-multiplexing again.
+After some bytes were received `server::do_()` is reentred again starting a
+asynch. write operation.
+
+The advantage over the ordinary `bind()` version is that the state of execution
+is preserved so that variables used by the read/write operations may have local
+scope. Stackfull coroutines (as boost.context provides) enable
+application-protocol stacks which can be more easily implemented.
+For instance, if only part of a message is received (some bytes are outstanding
+before message can be parsed or serviced), then the current state can be easily
+suspended/preserved (even from nested functions of the protocol stack)
+until the remaining bytes are received.
+
+ class server : public boost::enable_shared_from_this< server >,
+ private continuation
+ {
+ private:
+ boost::asio::ip::tcp::acceptor acceptor_;
+ boost::system::error_code ec_;
+ std::size_t n_;
+
+ void do_()
+ {
+ for (;;)
+ {
+ boost::asio::ip::tcp::socket socket( acceptor_.get_io_service() );
+ // accept connection request and enque *this for reading data from conenction
+ acceptor_.async_accept( socket, boost::bind( & server::operator(), this->shared_from_this(), _1, 0) );
+ // suspend() jumps back to operator() which returns to asio reactor
+ suspend();
+
+ while ( ! ec_)
+ {
+ // buffer has local scope!
+ boost::array< char, 1024 > buffer;
+
+ // enqueue *this to read some bytes from the connection into buffer
+ socket.async_read_some(
+ boost::asio::buffer( buffer),
+ boost::bind( & server::operator(), this->shared_from_this(), _1, _2) );
+ // suspend() jumps back to operator(); asio reactor
+ suspend();
+
+ // finish and return
+ if ( ec_) break;
+
+ // enqueue *this to write data from buffer to connection
+ boost::asio::async_write(
+ socket,
+ boost::asio::buffer( buffer, n_),
+ boost::bind( & server::operator(), this->shared_from_this(), _1, _2) );
+ // suspend() jumps back to operator(); asio reactor
+ suspend();
+ }
+ }
+ }
+
+ server( boost::asio::io_service & io_service, short port) :
+ continuation( boost::bind( & server::do_, this) ),
+ acceptor_( io_service, boost::asio::ip::tcp::endpoint( boost::asio::ip::tcp::v4(), port) ),
+ ec_(), n_( 0)
+ {}
+
+ public:
+ typedef boost::shared_ptr< server > ptr_t;
+
+ static ptr_t create( boost::asio::io_service & io_service, short port)
+ { return ptr_t( new server( io_service, port) ); }
+
+ void operator()( boost::system::error_code ec, size_t n)
+ {
+ ec_ = ec;
+ n_ = n;
+ // jump to coroutine (do_())
+ resume();
+ }
+ };
+
+ int main( int argc, char * argv[])
+ {
+ try
+ {
+ if ( argc != 2)
+ {
+ std::cerr << "Usage: echo_server <port>\n";
+ return 1;
+ }
+ {
+ boost::asio::io_service io_service;
+ io_service.post(
+ boost::bind(
+ & server::operator(),
+ server::create( io_service, boost::lexical_cast< short >( argv[1]) ),
+ boost::system::error_code(), 0) );
+ io_service.run();
+ }
+ std::cout << "Done" << std::endl;
+
+ return EXIT_SUCCESS;
+ }
+ catch ( std::exception const& e)
+ { std::cerr << "Exception: " << e.what() << std::endl; }
+
+ return EXIT_FAILURE;
+ }
+
+[endsect]

Added: trunk/libs/context/doc/config.qbk
==============================================================================
--- (empty file)
+++ trunk/libs/context/doc/config.qbk 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,60 @@
+[/
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt
+]
+
+[section:installtion How to build and install]
+
+__boost_context__ must be built for the particular compiler(s) and CPU architecture(s)s
+being targeted. __boost_context__ includes assembly code and, therefore, requires
+GNU AS for supported POSIX systems, and MASM for Windows systems.
+
+[note The architecture, instruction set, and address model are optional __boost_build__
+properties that must be given on the bjam command line, as shown in the table below.]
+
+[table
+ [[][]]
+ [
+ [ARM, UNIX, aapcs, elf]
+ [bjam toolset = gcc architecture = arm]
+ ]
+ [
+ [MIPS (32bit), UNIX, o32, elf]
+ [bjam toolset = gcc architecture = mips1]
+ ]
+ [
+ [I386, UNIX, sysv, elf]
+ [bjam toolset = gcc architecture = x86 instruction-set = i686 address-model = 32]
+ ]
+ [
+ [I386, UNIX, sysv, elf]
+ [bjam toolset = intel architecture = x86 instruction-set = i686 address-model = 32]
+ ]
+ [
+ [I386, Windows, ms, pe]
+ [bjam toolset = msvc-9.0 architecture = x86 instruction-set = i686 address-model = 32]
+ ]
+ [
+ [PowerPc (32bit), UNIX, sysv, elf]
+ [bjam toolset = gcc architecture = power address-model = 32]
+ ]
+ [
+ [PowerPc (64bit), UNIX, sysv, elf]
+ [bjam toolset = gcc architecture = power address-model = 64]
+ ]
+ [
+ [X86_64, UNIX, sysv, elf]
+ [bjam toolset = gcc architecture = x86 instruction-set = yorksfield address-model = 64]
+ ]
+ [
+ [X86_64, UNIX, sysv, elf]
+ [bjam toolset = intel architecture = x86 instruction-set = yorksfield address-model = 64]
+ ]
+ [
+ [X86_64, Windows, ms, pe]
+ [bjam toolset = msvc-10.0 architecture = x86 instruction-set = yorksfield address-model = 64]
+ ]
+]
+[endsect]

Added: trunk/libs/context/doc/context.qbk
==============================================================================
--- (empty file)
+++ trunk/libs/context/doc/context.qbk 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,79 @@
+[/
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt
+]
+
+[article Context
+ [quickbook 1.4]
+ [authors [Kowalke, Oliver]]
+ [copyright 2009 Oliver Kowalke]
+ [purpose C++ Library for swiching different user contexts]
+ [category text]
+ [license
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ [@http://www.boost.org/LICENSE_1_0.txt])
+ ]
+]
+
+
+[def __boost_build__ [*Boost.Build]]
+[def __boost_context__ [*Boost.Context]]
+[def __boost_fiber__ [*Boost.Fiber]]
+[def __boost_move__ [*Boost.Move]]
+[def __boost_task__ [*Boost.Task]]
+
+[template cs_example_link[link_text] [link context.examples.enumerator [link_text]]]
+[template context_link[link_text] [link context.context.context [link_text]]]
+[template stack_link[link_text] [link context.stack [link_text]]]
+[template preformance_link[link_text] [link context.performance [link_text]]]
+
+[def __context_fn__ ['context-function]]
+[def __coroutine__ ['coroutine]]
+[def __coroutines__ ['coroutines]]
+[def __coop_threads__ ['cooperative threads (userland threads)]]
+[def __fls__ ['fiber-local storage]]
+[def __guard_page__ ['guard-page]]
+[def __not_a_context__ ['not-a-context]]
+[def __stack__ [stack_link ['stack]]]
+[def __thread__ ['thread]]
+[def __threads__ ['threads]]
+[def __tls__ ['thread-local storage]]
+[def __stack_allocator__ ['StackAllocator]]
+[def __stack_allocator_concept__ ['StackAllocator concept]]
+[def __yield__ ['yield]]
+
+[def __fcontext__ ['fcontext_t]]
+[def __ucontext__ ['ucontext_t]]
+
+[def __fls_alloc__ ['::FlsAlloc()]]
+[def __fls_free__ ['::FlsFree()]]
+
+[def __bad_alloc__ ['std::bad_alloc]]
+[def __context__ [context_link ['context]]]
+[def __context_start__ ['context::start()]]
+[def __context_resume__ ['context::resume()]]
+[def __context_suspend__ ['context::suspend()]]
+[def __context_unwind__ ['context::unwind_stack()]]
+[def __forced_unwind__ ['forced_unwind]]
+[def __invalid_argument__ ['std::invalid_argument]]
+[def __stack_alloc__ ['allocate()]]
+[def __stack_dealloc__ ['deallocate()]]
+[def __stack_helper__ ['stack_helper]]
+
+[def __context_ns__ ['boost::contexts]]
+
+[include overview.qbk]
+[include config.qbk]
+[include context_ref.qbk]
+[include stack_ref.qbk]
+[include fcontext.qbk]
+[include examples.qbk]
+[include performance.qbk]
+[include tested.qbk]
+[include rationale.qbk]
+[include reference.qbk]
+[include todo.qbk]
+[include acknowledgements.qbk]

Added: trunk/libs/context/doc/context.xml
==============================================================================
--- (empty file)
+++ trunk/libs/context/doc/context.xml 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,3473 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE article PUBLIC "-//Boost//DTD BoostBook XML V1.0//EN" "http://www.boost.org/tools/boostbook/dtd/boostbook.dtd">
+<article id="context" last-revision="$Date: 2012/02/01 18:25:59 $" xmlns:xi="http://www.w3.org/2001/XInclude">
+ <title>Context</title>
+ <articleinfo>
+ <authorgroup>
+ <author>
+ <firstname>Oliver</firstname> <surname>Kowalke</surname>
+ </author>
+ </authorgroup>
+ <copyright>
+ <year>2009</year> <holder>Oliver Kowalke</holder>
+ </copyright>
+ <legalnotice>
+ <para>
+ Distributed under the Boost Software License, Version 1.0. (See accompanying
+ file LICENSE_1_0.txt or copy at <ulink url="http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt>)
+ </para>
+ </legalnotice>
+ <articlepurpose>
+ C++ Library for swiching different user contexts
+ </articlepurpose>
+ <articlecategory name="category:text"></articlecategory>
+ </articleinfo>
+ <section id="context.overview">
+ <title><link linkend="context.overview">Overview</link></title>
+ <para>
+ <emphasis role="bold">Boost.Context</emphasis> is a foundational library that
+ provides a sort of cooperative multitasking on a single thread. By providing
+ an abstraction of the current execution state in the current thread, including
+ the stack (with local variables) and stack pointer, all registers and CPU flags,
+ and the instruction pointer, a <link linkend="context.context.context"><emphasis>context</emphasis></link>
+ instance represents a specific point in the application's execution path. This
+ is useful for building higher-level abstractions, like <emphasis>coroutines</emphasis>,
+ <emphasis>cooperative threads (userland threads)</emphasis> or an aquivalent
+ to <ulink url="http://msdn.microsoft.com/en-us/library/9k7k7cf0%28v=vs.80%29.aspx">C#
+ keyword <emphasis>yield</emphasis></ulink> in C++ ( <link linkend="context.examples.enumerator">see
+ enumerator example</link>).
+ </para>
+ <para>
+ A <link linkend="context.context.context"><emphasis>context</emphasis></link>
+ provides the means to suspend the current execution path and to transfer execution
+ control, thereby permitting another <link linkend="context.context.context"><emphasis>context</emphasis></link>
+ to run on the current thread. This stateful transfer mechanism enables a <link
+ linkend="context.context.context"><emphasis>context</emphasis></link> to suspend
+ execution from within nested functions and, later, to resume from where it
+ was suspended. While the execution path represented by a <link linkend="context.context.context"><emphasis>context</emphasis></link>
+ only runs on a single thread, it can be migrated to another thread at any given
+ time.
+ </para>
+ <para>
+ A context switch between threads requires system calls (involving the OS kernel),
+ which can cost thousands of CPU cycles on x86 CPUs. By contrast, transferring
+ control among them requires only a few hundred CPU cycles because it does not
+ involve system calls as it is done within a single thread.
+ </para>
+ <para>
+ In order to use the classes and functions described here, you can either include
+ the specific headers specified by the descriptions of each class or function,
+ or include the master library header:
+ </para>
+
+<programlisting><phrase role="preprocessor">#include</phrase> <phrase role="special"><</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">context</phrase><phrase role="special">/</phrase><phrase role="identifier">all</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">></phrase>
+</programlisting>
+ <para>
+ which includes all the other headers in turn.
+ </para>
+ <para>
+ All functions and classes are contained in the namespace <emphasis>boost::contexts</emphasis>.
+ </para>
+ <para>
+ <emphasis role="bold">Boost.Context</emphasis> depends on <emphasis role="bold">Boost.Move</emphasis>.
+ </para>
+ </section>
+ <section id="context.installtion">
+ <title><link linkend="context.installtion">How to build and install</link></title>
+ <para>
+ <emphasis role="bold">Boost.Context</emphasis> must be built for the particular
+ compiler(s) and CPU architecture(s)s being targeted. <emphasis role="bold">Boost.Context</emphasis>
+ includes assembly code and, therefore, requires GNU AS for supported POSIX
+ systems, and MASM for Windows systems.
+ </para>
+ <note>
+ <para>
+ The architecture, instruction set, and address model are optional <emphasis
+ role="bold">Boost.Build</emphasis> properties that must be given on the bjam
+ command line, as shown in the table below.
+ </para>
+ </note>
+ <informaltable frame="all">
+ <tgroup cols="2">
+ <thead>
+ <row>
+ <entry>
+ </entry>
+ <entry>
+ </entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>
+ <para>
+ ARM, UNIX, aapcs, elf
+ </para>
+ </entry>
+ <entry>
+ <para>
+ bjam toolset = gcc architecture = arm
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>
+ <para>
+ MIPS (32bit), UNIX, o32, elf
+ </para>
+ </entry>
+ <entry>
+ <para>
+ bjam toolset = gcc architecture = mips1 <footnote>
+ <para>
+ Because of a bug in shared_ptr you have to apply a patch 'patches/llsc-mips.patch'
+ to shared_ptr or provide cxxflags="-mips2" at bjam command-line.
+ </para>
+ </footnote>
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>
+ <para>
+ I386, UNIX, sysv, elf
+ </para>
+ </entry>
+ <entry>
+ <para>
+ bjam toolset = gcc architecture = x86 instruction-set = i686 address-model
+ = 32
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>
+ <para>
+ I386, UNIX, sysv, elf
+ </para>
+ </entry>
+ <entry>
+ <para>
+ bjam toolset = intel architecture = x86 instruction-set = i686 address-model
+ = 32
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>
+ <para>
+ I386, Windows, ms, pe
+ </para>
+ </entry>
+ <entry>
+ <para>
+ bjam toolset = msvc-9.0 architecture = x86 instruction-set = i686
+ address-model = 32
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>
+ <para>
+ PowerPc (32bit), UNIX, sysv, elf
+ </para>
+ </entry>
+ <entry>
+ <para>
+ bjam toolset = gcc architecture = power address-model = 32
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>
+ <para>
+ PowerPc (64bit), UNIX, sysv, elf
+ </para>
+ </entry>
+ <entry>
+ <para>
+ bjam toolset = gcc architecture = power address-model = 64
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>
+ <para>
+ X86_64, UNIX, sysv, elf
+ </para>
+ </entry>
+ <entry>
+ <para>
+ bjam toolset = gcc architecture = x86 instruction-set = yorksfield
+ address-model = 64
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>
+ <para>
+ X86_64, UNIX, sysv, elf
+ </para>
+ </entry>
+ <entry>
+ <para>
+ bjam toolset = intel architecture = x86 instruction-set = yorksfield
+ address-model = 64
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>
+ <para>
+ X86_64, Windows, ms, pe
+ </para>
+ </entry>
+ <entry>
+ <para>
+ bjam toolset = msvc-10.0 architecture = x86 instruction-set = yorksfield
+ address-model = 64
+ </para>
+ </entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </informaltable>
+ </section>
+ <section id="context.context">
+ <title><link linkend="context.context">Context</link></title>
+ <para>
+ Each instance of <link linkend="context.context.context"><emphasis>context</emphasis></link>
+ represents a context (CPU registers and stack space) of execution or <emphasis>not-a-context</emphasis>.
+ Objects of type <link linkend="context.context.context"><emphasis>context</emphasis></link>
+ are moveable but not copyable and can be returned by a function.
+ </para>
+
+<programlisting><phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">context</phrase> <phrase role="identifier">make_context</phrase><phrase role="special">();</phrase>
+
+<phrase role="keyword">void</phrase> <phrase role="identifier">f</phrase><phrase role="special">()</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">(</phrase> <phrase role="identifier">make_context</phrase><phrase role="special">()</phrase> <phrase role="special">);</phrase>
+ <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">resume</phrase><phrase role="special">();</phrase>
+<phrase role="special">}</phrase>
+</programlisting>
+ <note>
+ <para>
+ <emphasis role="bold">Boost.Move</emphasis> is used to emulate rvalue references.
+ </para>
+ </note>
+ <warning>
+ <para>
+ If contexts are used in a multithreaded application, they can migrated between
+ threads, but must not reference <emphasis>thread-local storage</emphasis>.
+ </para>
+ </warning>
+ <note>
+ <para>
+ If <emphasis>fiber-local storage</emphasis> is used on Windows, the user
+ is responsible for calling <emphasis>::FlsAlloc()</emphasis>, <emphasis>::FlsFree()</emphasis>.
+ </para>
+ </note>
+ <anchor id="context.context.executing_a_context"/>
+ <bridgehead renderas="sect3">
+ <link linkend="context.context.executing_a_context">Executing a context</link>
+ </bridgehead>
+ <para>
+ A new context is created from a callable object (known as the <emphasis>context-function</emphasis>).
+ The stack size, stack unwinding behavior, and context termination behavior
+ are determined by additional arguments.
+ </para>
+ <para>
+ The <link linkend="context.context.context"><emphasis>context</emphasis></link>
+ constructor uses a <emphasis>StackAllocator concept</emphasis> to allocate
+ an associated stack, and the destructor uses the same <emphasis>StackAllocator
+ concept</emphasis> to deallocate the stack. The default <emphasis>StackAllocator
+ concept</emphasis> is <emphasis>StackAllocator</emphasis>, but a custom stack-allocator
+ can be passed to the constructor.
+ </para>
+ <para>
+ Additional arguments needed by a <emphasis>context-function</emphasis> are
+ supplied as additional arguments to the context constructor.
+ </para>
+
+<programlisting><phrase role="keyword">void</phrase> <phrase role="identifier">f</phrase><phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">i</phrase><phrase role="special">);</phrase>
+
+<phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">(</phrase> <phrase role="identifier">f</phrase><phrase role="special">,</phrase> <phrase role="number">42</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">default_stacksize</phrase><phrase role="special">(),</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">no_stack_unwind</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">return_to_caller</phrase><phrase role="special">);</phrase>
+</programlisting>
+ <para>
+ The <emphasis>context-function</emphasis>, as well as its arguments, if any,
+ are copied into the context's state. If a reference is required, use boost::ref.
+ </para>
+ <para>
+ The maximum number of arguments of <emphasis>context-function</emphasis> is
+ defined by BOOST_CONTEXT_ARITY (default is 10 and might be increased).
+ </para>
+ <para>
+ Calling <emphasis>context::start()</emphasis> invokes the <emphasis>context-function</emphasis>
+ in a newly created context complete with registers, flags, stack and instruction
+ pointers. When control should be returned to the original calling context,
+ call <emphasis>context::suspend()</emphasis>. The current context information
+ (registers, flags, and stack and instruction pointers) is saved and the original
+ context information is restored. Calling <emphasis>context::resume()</emphasis>
+ resumes execution in the second context after saving the new state of the original
+ context. Note that <emphasis>context::start()</emphasis> must be called first
+ and only once.
+ </para>
+
+<programlisting><phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">;</phrase>
+
+<phrase role="keyword">void</phrase> <phrase role="identifier">fn</phrase><phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">j</phrase><phrase role="special">)</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="keyword">for</phrase><phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">i</phrase> <phrase role="special">=</phrase> <phrase role="number">0</phrase><phrase role="special">;</phrase> <phrase role="identifier">i</phrase> <phrase role="special"><</phrase> <phrase role="identifier">j</phrase><phrase role="special">;</phrase> <phrase role="special">++</phrase><phrase role="identifier">i</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"fn(): local variable i == "</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">i</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+
+ <phrase role="comment">// save current context
+</phrase> <phrase role="comment">// value of local variable is preserved
+</phrase> <phrase role="comment">// transfer execution control back to main()
+</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">suspend</phrase><phrase role="special">();</phrase>
+
+ <phrase role="comment">// ctx.resume() was called
+</phrase> <phrase role="comment">// execution control transfered back from main()
+</phrase> <phrase role="special">}</phrase>
+<phrase role="special">}</phrase>
+
+<phrase role="keyword">int</phrase> <phrase role="identifier">main</phrase><phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">argc</phrase><phrase role="special">,</phrase> <phrase role="keyword">char</phrase> <phrase role="special">*</phrase> <phrase role="identifier">argv</phrase><phrase role="special">[])</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="identifier">ctx</phrase> <phrase role="special">=</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">context</phrase><phrase role="special">(</phrase> <phrase role="identifier">fn</phrase><phrase role="special">,</phrase> <phrase role="number">7</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">default_stacksize</phrase><phrase role="special">(),</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">no_stack_unwind</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">return_to_caller</phrase><phrase role="special">);</phrase>
+
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"main() starts context ctx"</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+ <phrase role="comment">// start the context ctx for the first time; enter fn()
+</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">start</phrase><phrase role="special">();</phrase>
+
+ <phrase role="comment">// ctx.suspend() was called so we returned from start()
+</phrase> <phrase role="keyword">while</phrase> <phrase role="special">(</phrase> <phrase role="special">!</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">is_complete</phrase><phrase role="special">()</phrase> <phrase role="special">)</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"main() calls context ctx"</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+ <phrase role="comment">// resume inside fn()
+</phrase> <phrase role="comment">// execution control is transfered to ctx
+</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">resume</phrase><phrase role="special">();</phrase>
+
+ <phrase role="comment">// ctx.suspend() was called within fn()
+</phrase> <phrase role="special">}</phrase>
+
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"Done"</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+
+ <phrase role="keyword">return</phrase> <phrase role="identifier">EXIT_SUCCESS</phrase><phrase role="special">;</phrase>
+<phrase role="special">}</phrase>
+
+<phrase role="identifier">output</phrase><phrase role="special">:</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">starts</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="identifier">local</phrase> <phrase role="identifier">variable</phrase> <phrase role="identifier">i</phrase> <phrase role="special">==</phrase> <phrase role="number">0</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">calls</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="identifier">local</phrase> <phrase role="identifier">variable</phrase> <phrase role="identifier">i</phrase> <phrase role="special">==</phrase> <phrase role="number">1</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">calls</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="identifier">local</phrase> <phrase role="identifier">variable</phrase> <phrase role="identifier">i</phrase> <phrase role="special">==</phrase> <phrase role="number">2</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">calls</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="identifier">local</phrase> <phrase role="identifier">variable</phrase> <phrase role="identifier">i</phrase> <phrase role="special">==</phrase> <phrase role="number">3</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">calls</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="identifier">local</phrase> <phrase role="identifier">variable</phrase> <phrase role="identifier">i</phrase> <phrase role="special">==</phrase> <phrase role="number">4</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">calls</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="identifier">local</phrase> <phrase role="identifier">variable</phrase> <phrase role="identifier">i</phrase> <phrase role="special">==</phrase> <phrase role="number">5</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">calls</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="identifier">local</phrase> <phrase role="identifier">variable</phrase> <phrase role="identifier">i</phrase> <phrase role="special">==</phrase> <phrase role="number">6</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">calls</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+ <phrase role="identifier">Done</phrase>
+</programlisting>
+ <warning>
+ <para>
+ Calling <emphasis>context::resume()</emphasis> from inside the same context
+ results in undefined behaviour.
+ </para>
+ </warning>
+ <note>
+ <para>
+ In contrast to threads, which are preemtive, <link linkend="context.context.context"><emphasis>context</emphasis></link>
+ switches are cooperative (programmer controls when switch will happen). The
+ kernel is not involved in the context switches.
+ </para>
+ </note>
+ <anchor id="context.context.transfer_of_data"/>
+ <bridgehead renderas="sect3">
+ <link linkend="context.context.transfer_of_data">Transfer of data</link>
+ </bridgehead>
+ <para>
+ The argument passed to <emphasis>context::resume()</emphasis>, in one context,
+ is returned by <emphasis>context::suspend()</emphasis> in the other context.
+ The intptr_t passed to <emphasis>context::suspend()</emphasis>, in one context,
+ is returned by <emphasis>context::resume()</emphasis> (or <emphasis>context::start()</emphasis>,
+ depending upon which function was called previously) in the other context.
+ <emphasis>context::start()</emphasis> has no argument because it enters the
+ start of the function, and there is no previous call to <emphasis>context::suspend()</emphasis>
+ to return a value.
+ </para>
+
+<programlisting><phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">;</phrase>
+
+<phrase role="keyword">void</phrase> <phrase role="identifier">fn</phrase><phrase role="special">()</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="keyword">int</phrase> <phrase role="identifier">i</phrase> <phrase role="special">=</phrase> <phrase role="number">7</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"fn(): local variable i == "</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">i</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+
+ <phrase role="comment">// save current context
+</phrase> <phrase role="comment">// transfer execution control back to caller
+</phrase> <phrase role="comment">// pass content of variable back
+</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">j</phrase> <phrase role="special">=</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">suspend</phrase><phrase role="special">(</phrase> <phrase role="identifier">i</phrase><phrase role="special">);</phrase>
+ <phrase role="comment">// j == 10 because x == 10 in main()
+</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"transfered value: "</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">j</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+<phrase role="special">}</phrase>
+
+<phrase role="keyword">int</phrase> <phrase role="identifier">main</phrase><phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">argc</phrase><phrase role="special">,</phrase> <phrase role="keyword">char</phrase> <phrase role="special">*</phrase> <phrase role="identifier">argv</phrase><phrase role="special">[])</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="identifier">ctx</phrase> <phrase role="special">=</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">context</phrase><phrase role="special">(</phrase> <phrase role="identifier">fn</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">default_stacksize</phrase><phrase role="special">(),</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">no_stack_unwind</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">return_to_caller</phrase><phrase role="special">);</phrase>
+
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"main() calls context ctx"</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+
+ <phrase role="comment">// start the context ctx for the first time
+</phrase> <phrase role="comment">// enter fn()
+</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">x</phrase> <phrase role="special">=</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">start</phrase><phrase role="special">();</phrase>
+ <phrase role="comment">// x == 7 because i == 7 in fn()
+</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"transfered value: "</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">x</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+
+ <phrase role="identifier">x</phrase> <phrase role="special">=</phrase> <phrase role="number">10</phrase><phrase role="special">;</phrase>
+ <phrase role="comment">// ctx.suspend() was called so we returned from start()
+</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">resume</phrase><phrase role="special">(</phrase> <phrase role="identifier">x</phrase><phrase role="special">);</phrase>
+
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"Done"</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+
+ <phrase role="keyword">return</phrase> <phrase role="identifier">EXIT_SUCCESS</phrase><phrase role="special">;</phrase>
+<phrase role="special">}</phrase>
+
+<phrase role="identifier">output</phrase><phrase role="special">:</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">calls</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="identifier">local</phrase> <phrase role="identifier">variable</phrase> <phrase role="identifier">i</phrase> <phrase role="special">==</phrase> <phrase role="number">7</phrase>
+ <phrase role="identifier">transfered</phrase> <phrase role="identifier">value</phrase><phrase role="special">:</phrase> <phrase role="number">7</phrase>
+ <phrase role="identifier">transfered</phrase> <phrase role="identifier">value</phrase><phrase role="special">:</phrase> <phrase role="number">10</phrase>
+ <phrase role="identifier">Done</phrase>
+</programlisting>
+ <anchor id="context.context.exceptions_in__emphasis_context_function__emphasis_"/>
+ <bridgehead renderas="sect3">
+ <link linkend="context.context.exceptions_in__emphasis_context_function__emphasis_">Exceptions
+ in <emphasis>context-function</emphasis></link>
+ </bridgehead>
+ <para>
+ If the <emphasis>context-function</emphasis> emits an exception, std::terminate()
+ is called.
+ </para>
+ <important>
+ <para>
+ Code executed by context must not prevent the propagation of the <emphasis>forced_unwind</emphasis>
+ exception. Absorbing that exception will cause stack unwinding to fail. Thus,
+ any code that catches all exceptions must rethrow the pending exception.
+ </para>
+ </important>
+
+<programlisting><phrase role="keyword">try</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="comment">// code that might throw
+</phrase><phrase role="special">}</phrase>
+<phrase role="keyword">catch</phrase><phrase role="special">(</phrase> <phrase role="identifier">forced_unwind</phrase><phrase role="special">)</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="keyword">throw</phrase><phrase role="special">;</phrase>
+<phrase role="special">}</phrase>
+<phrase role="keyword">catch</phrase><phrase role="special">(...)</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="comment">// possibly not rethrow pending exception
+</phrase><phrase role="special">}</phrase>
+</programlisting>
+ <anchor id="context.context.handling_execution_context_termination"/>
+ <bridgehead renderas="sect3">
+ <link linkend="context.context.handling_execution_context_termination">Handling
+ execution context termination</link>
+ </bridgehead>
+ <para>
+ The last context constructor argument is an enumerated type which determines
+ what should happen when the context is complete (that is, when the <emphasis>context-function</emphasis>
+ returns). The available values are <code><phrase role="identifier">return_to_caller</phrase></code>
+ and <code><phrase role="identifier">exit_application</phrase></code>.
+ </para>
+ <para>
+ When the last constructor argument is <code><phrase role="identifier">return_to_caller</phrase></code>,
+ execution control is transferred back to the last invocation of <emphasis>context::start()</emphasis>
+ or <emphasis>context::resume()</emphasis> when the context is complete, as
+ shown in this example:
+ </para>
+
+<programlisting><phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">;</phrase>
+
+<phrase role="keyword">void</phrase> <phrase role="identifier">fn</phrase><phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">j</phrase><phrase role="special">)</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="keyword">for</phrase><phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">i</phrase> <phrase role="special">=</phrase> <phrase role="number">0</phrase><phrase role="special">;</phrase> <phrase role="identifier">i</phrase> <phrase role="special"><</phrase> <phrase role="identifier">j</phrase><phrase role="special">;</phrase> <phrase role="special">++</phrase><phrase role="identifier">i</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"fn(): local variable i == "</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">i</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">suspend</phrase><phrase role="special">();</phrase>
+ <phrase role="special">}</phrase>
+
+ <phrase role="comment">// fn() returns
+</phrase> <phrase role="comment">// execution control is transfered back to main()
+</phrase><phrase role="special">}</phrase>
+
+<phrase role="keyword">int</phrase> <phrase role="identifier">main</phrase><phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">argc</phrase><phrase role="special">,</phrase> <phrase role="keyword">char</phrase> <phrase role="special">*</phrase> <phrase role="identifier">argv</phrase><phrase role="special">[])</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="identifier">ctx</phrase> <phrase role="special">=</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">context</phrase><phrase role="special">(</phrase> <phrase role="identifier">fn</phrase><phrase role="special">,</phrase> <phrase role="number">7</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">default_stacksize</phrase><phrase role="special">(),</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">no_stack_unwind</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">return_to_caller</phrase><phrase role="special">);</phrase>
+
+ <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">start</phrase><phrase role="special">();</phrase>
+ <phrase role="keyword">while</phrase> <phrase role="special">(</phrase> <phrase role="special">!</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">is_complete</phrase><phrase role="special">()</phrase> <phrase role="special">)</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"main() calls context ctx"</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">resume</phrase><phrase role="special">();</phrase>
+ <phrase role="special">}</phrase>
+
+ <phrase role="comment">// fn() returned; the context is complete
+</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"Done"</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+
+ <phrase role="keyword">return</phrase> <phrase role="identifier">EXIT_SUCCESS</phrase><phrase role="special">;</phrase>
+<phrase role="special">}</phrase>
+
+<phrase role="identifier">output</phrase><phrase role="special">:</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="identifier">local</phrase> <phrase role="identifier">variable</phrase> <phrase role="identifier">i</phrase> <phrase role="special">==</phrase> <phrase role="number">0</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">calls</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="identifier">local</phrase> <phrase role="identifier">variable</phrase> <phrase role="identifier">i</phrase> <phrase role="special">==</phrase> <phrase role="number">1</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">calls</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="identifier">local</phrase> <phrase role="identifier">variable</phrase> <phrase role="identifier">i</phrase> <phrase role="special">==</phrase> <phrase role="number">2</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">calls</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="identifier">local</phrase> <phrase role="identifier">variable</phrase> <phrase role="identifier">i</phrase> <phrase role="special">==</phrase> <phrase role="number">3</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">calls</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="identifier">local</phrase> <phrase role="identifier">variable</phrase> <phrase role="identifier">i</phrase> <phrase role="special">==</phrase> <phrase role="number">4</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">calls</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="identifier">local</phrase> <phrase role="identifier">variable</phrase> <phrase role="identifier">i</phrase> <phrase role="special">==</phrase> <phrase role="number">5</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">calls</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="identifier">local</phrase> <phrase role="identifier">variable</phrase> <phrase role="identifier">i</phrase> <phrase role="special">==</phrase> <phrase role="number">6</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">calls</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+ <phrase role="identifier">Done</phrase>
+</programlisting>
+ <para>
+ When the last constructor argument is <code><phrase role="identifier">exit_application</phrase></code>,
+ the application terminates with an exit status of zero when the context is
+ complete, as shown in the following example:
+ </para>
+
+<programlisting><phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">;</phrase>
+
+<phrase role="keyword">void</phrase> <phrase role="identifier">fn</phrase><phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">j</phrase><phrase role="special">)</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="keyword">for</phrase><phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">i</phrase> <phrase role="special">=</phrase> <phrase role="number">0</phrase><phrase role="special">;</phrase> <phrase role="identifier">i</phrase> <phrase role="special"><</phrase> <phrase role="identifier">j</phrase><phrase role="special">;</phrase> <phrase role="special">++</phrase><phrase role="identifier">i</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"fn(): local variable i == "</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">i</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">suspend</phrase><phrase role="special">();</phrase>
+ <phrase role="special">}</phrase>
+
+ <phrase role="comment">// fn() returns
+</phrase> <phrase role="comment">// application will terminate
+</phrase><phrase role="special">}</phrase>
+
+<phrase role="keyword">int</phrase> <phrase role="identifier">main</phrase><phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">argc</phrase><phrase role="special">,</phrase> <phrase role="keyword">char</phrase> <phrase role="special">*</phrase> <phrase role="identifier">argv</phrase><phrase role="special">[])</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="identifier">ctx</phrase> <phrase role="special">=</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">context</phrase><phrase role="special">(</phrase> <phrase role="identifier">fn</phrase><phrase role="special">,</phrase> <phrase role="number">7</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">default_stacksize</phrase><phrase role="special">(),</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">no_stack_unwind</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">exit_application</phrase><phrase role="special">);</phrase>
+
+ <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">start</phrase><phrase role="special">();</phrase>
+ <phrase role="keyword">while</phrase> <phrase role="special">(</phrase> <phrase role="special">!</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">is_complete</phrase><phrase role="special">()</phrase> <phrase role="special">)</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"main() calls context ctx"</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">resume</phrase><phrase role="special">();</phrase>
+ <phrase role="special">}</phrase>
+
+ <phrase role="comment">// never reached
+</phrase> <phrase role="keyword">return</phrase> <phrase role="identifier">EXIT_SUCCESS</phrase><phrase role="special">;</phrase>
+<phrase role="special">}</phrase>
+
+<phrase role="identifier">output</phrase><phrase role="special">:</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">()</phrase> <phrase role="identifier">calls</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="identifier">local</phrase> <phrase role="identifier">variable</phrase> <phrase role="identifier">i</phrase> <phrase role="special">==</phrase> <phrase role="number">1</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">calls</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="identifier">local</phrase> <phrase role="identifier">variable</phrase> <phrase role="identifier">i</phrase> <phrase role="special">==</phrase> <phrase role="number">2</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">calls</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="identifier">local</phrase> <phrase role="identifier">variable</phrase> <phrase role="identifier">i</phrase> <phrase role="special">==</phrase> <phrase role="number">3</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">calls</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="identifier">local</phrase> <phrase role="identifier">variable</phrase> <phrase role="identifier">i</phrase> <phrase role="special">==</phrase> <phrase role="number">4</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">calls</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="identifier">local</phrase> <phrase role="identifier">variable</phrase> <phrase role="identifier">i</phrase> <phrase role="special">==</phrase> <phrase role="number">5</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">calls</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="identifier">local</phrase> <phrase role="identifier">variable</phrase> <phrase role="identifier">i</phrase> <phrase role="special">==</phrase> <phrase role="number">6</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">calls</phrase> <phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase>
+</programlisting>
+ <anchor id="context.context.chaining_contexts"/>
+ <bridgehead renderas="sect3">
+ <link linkend="context.context.chaining_contexts">Chaining contexts</link>
+ </bridgehead>
+ <para>
+ <emphasis role="bold">Boost.Context</emphasis> provides the ability to chain
+ context instances by passing a reference to another context, other than that
+ <emphasis>not-a-context</emphasis>, as the last constructor argument. In this
+ way, it is possible to create a chain of contexts. Depending on the <code><phrase
+ role="identifier">do_return</phrase></code> argument in the constructor of
+ the last context in the chain, the application terminates or execution control
+ is transferred back to the last invocation of <emphasis>context::resume()</emphasis>.
+ Each call of <emphasis>context::suspend()</emphasis>, for the chained context
+ instances, will return to <emphasis>context::resume()</emphasis>.
+ </para>
+
+<programlisting><phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">context</phrase> <phrase role="identifier">ctx2</phrase><phrase role="special">;</phrase>
+
+<phrase role="keyword">void</phrase> <phrase role="identifier">fn1</phrase><phrase role="special">()</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"fn1(): when this function returns fn2() will be entered"</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+<phrase role="special">}</phrase>
+
+<phrase role="keyword">void</phrase> <phrase role="identifier">fn2</phrase><phrase role="special">()</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"fn2(): first time entered"</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">ctx2</phrase><phrase role="special">.</phrase><phrase role="identifier">suspend</phrase><phrase role="special">();</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"fn2(): second time entered\n"</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"fn2(): return to main()"</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+<phrase role="special">}</phrase>
+
+<phrase role="keyword">int</phrase> <phrase role="identifier">main</phrase><phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">argc</phrase><phrase role="special">,</phrase> <phrase role="keyword">char</phrase> <phrase role="special">*</phrase> <phrase role="identifier">argv</phrase><phrase role="special">[])</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="comment">// ctx2 will return to ctx2.resume()
+</phrase> <phrase role="identifier">ctx2</phrase> <phrase role="special">=</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">context</phrase><phrase role="special">(</phrase>
+ <phrase role="identifier">fn2</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">default_stacksize</phrase><phrase role="special">(),</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">no_stack_unwind</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">return_to_caller</phrase><phrase role="special">);</phrase>
+
+ <phrase role="comment">// ctx1 defines ctx2 as its successor
+</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">context</phrase> <phrase role="identifier">ctx1</phrase><phrase role="special">(</phrase>
+ <phrase role="identifier">fn1</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">default_stacksize</phrase><phrase role="special">(),</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">no_stack_unwind</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">ctx2</phrase><phrase role="special">);</phrase>
+
+ <phrase role="comment">// transfer execution control to ctx1
+</phrase> <phrase role="comment">// fn1() is entered
+</phrase> <phrase role="identifier">ctx1</phrase><phrase role="special">.</phrase><phrase role="identifier">start</phrase><phrase role="special">();</phrase>
+
+ <phrase role="comment">// ctx2.suspend() was called
+</phrase> <phrase role="special">}</phrase>
+
+ <phrase role="comment">// ctx2 was already started by ctx1
+</phrase> <phrase role="identifier">ctx2</phrase><phrase role="special">.</phrase><phrase role="identifier">resume</phrase><phrase role="special">();</phrase>
+
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"Done"</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+
+ <phrase role="keyword">return</phrase> <phrase role="identifier">EXIT_SUCCESS</phrase><phrase role="special">;</phrase>
+<phrase role="special">}</phrase>
+
+<phrase role="identifier">output</phrase><phrase role="special">:</phrase>
+ <phrase role="identifier">fn1</phrase><phrase role="special">():</phrase> <phrase role="identifier">when</phrase> <phrase role="keyword">this</phrase> <phrase role="identifier">function</phrase> <phrase role="identifier">returns</phrase> <phrase role="identifier">fn2</phrase><phrase role="special">()</phrase> <phrase role="identifier">will</phrase> <phrase role="identifier">be</phrase> <phrase role="identifier">entered</phrase>
+ <phrase role="identifier">fn2</phrase><phrase role="special">():</phrase> <phrase role="identifier">first</phrase> <phrase role="identifier">time</phrase> <phrase role="identifier">entered</phrase>
+ <phrase role="identifier">fn2</phrase><phrase role="special">():</phrase> <phrase role="identifier">second</phrase> <phrase role="identifier">time</phrase> <phrase role="identifier">entered</phrase>
+ <phrase role="identifier">fnd2</phrase><phrase role="special">():</phrase> <phrase role="keyword">return</phrase> <phrase role="identifier">to</phrase> <phrase role="identifier">main</phrase><phrase role="special">()</phrase>
+ <phrase role="identifier">Done</phrase>
+</programlisting>
+ <important>
+ <para>
+ Call <emphasis>context::start()</emphasis> only on the first context in a
+ chain.
+ </para>
+ </important>
+ <anchor id="context.context.stack_unwinding"/>
+ <bridgehead renderas="sect3">
+ <link linkend="context.context.stack_unwinding">Stack unwinding</link>
+ </bridgehead>
+ <para>
+ Sometimes it is necessary to unwind the stack of an unfinished context to destroy
+ local stack variables so they can release allocated resources (RAII pattern).
+ The next to last argument of the context constructor, <code><phrase role="identifier">do_unwind</phrase></code>,
+ indicates whether the destructor should unwind the stack. Stack unwinding can
+ also be triggered by calling <emphasis>context::unwind_stack()</emphasis>.
+ </para>
+ <para>
+ Stack unwinding assumes the following preconditions:
+ </para>
+ <itemizedlist>
+ <listitem>
+ <simpara>
+ The context is not <emphasis>not-a-context</emphasis>
+ </simpara>
+ </listitem>
+ <listitem>
+ <simpara>
+ The context is not complete
+ </simpara>
+ </listitem>
+ <listitem>
+ <simpara>
+ The context is not running
+ </simpara>
+ </listitem>
+ <listitem>
+ <simpara>
+ The context owns a stack
+ </simpara>
+ </listitem>
+ </itemizedlist>
+ <para>
+ After unwinding, a <link linkend="context.context.context"><emphasis>context</emphasis></link>
+ is complete.
+ </para>
+
+<programlisting><phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">context</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">;</phrase>
+
+<phrase role="keyword">struct</phrase> <phrase role="identifier">X</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="identifier">X</phrase><phrase role="special">()</phrase>
+ <phrase role="special">{</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"X()"</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase> <phrase role="special">}</phrase>
+
+ <phrase role="special">~</phrase><phrase role="identifier">X</phrase><phrase role="special">()</phrase>
+ <phrase role="special">{</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"~X()"</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase> <phrase role="special">}</phrase>
+<phrase role="special">};</phrase>
+
+<phrase role="keyword">void</phrase> <phrase role="identifier">fn</phrase><phrase role="special">()</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="identifier">X</phrase> <phrase role="identifier">x</phrase><phrase role="special">;</phrase>
+
+ <phrase role="keyword">for</phrase><phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">i</phrase> <phrase role="special">=</phrase> <phrase role="number">0</phrase><phrase role="special">;;</phrase> <phrase role="special">++</phrase><phrase role="identifier">i</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"fn(): "</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">i</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+ <phrase role="comment">// transfer execution control back to main()
+</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">suspend</phrase><phrase role="special">();</phrase>
+ <phrase role="special">}</phrase>
+<phrase role="special">}</phrase>
+
+<phrase role="keyword">int</phrase> <phrase role="identifier">main</phrase><phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">argc</phrase><phrase role="special">,</phrase> <phrase role="keyword">char</phrase> <phrase role="special">*</phrase> <phrase role="identifier">argv</phrase><phrase role="special">[])</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="identifier">ctx</phrase> <phrase role="special">=</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">context</phrase><phrase role="special">(</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">default_stacksize</phrase><phrase role="special">(),</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">no_stack_unwind</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">return_to_caller</phrase><phrase role="special">);</phrase>
+ <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">start</phrase><phrase role="special">();</phrase>
+ <phrase role="keyword">for</phrase> <phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">i</phrase> <phrase role="special">=</phrase> <phrase role="number">0</phrase><phrase role="special">;</phrase> <phrase role="identifier">i</phrase> <phrase role="special"><</phrase> <phrase role="number">5</phrase><phrase role="special">;</phrase> <phrase role="special">++</phrase><phrase role="identifier">i</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="comment">// transfer execution control to fn()
+</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">resume</phrase><phrase role="special">();</phrase>
+ <phrase role="special">}</phrase>
+
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"ctx is complete: "</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">boolalpha</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">is_complete</phrase><phrase role="special">()</phrase> <phrase role="special"><<</phrase> <phrase role="string">"\n"</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"call ctx.unwind_stack()"</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+
+ <phrase role="comment">// unwind the stack
+</phrase> <phrase role="comment">// X::~X() will be called
+</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">unwind_stack</phrase><phrase role="special">();</phrase> <phrase role="comment">// unwind the stack
+</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"ctx is complete: "</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">boolalpha</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">is_complete</phrase><phrase role="special">()</phrase> <phrase role="special"><<</phrase> <phrase role="string">"\n"</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"Done"</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+
+ <phrase role="keyword">return</phrase> <phrase role="identifier">EXIT_SUCCESS</phrase><phrase role="special">;</phrase>
+<phrase role="special">}</phrase>
+
+<phrase role="identifier">output</phrase><phrase role="special">:</phrase>
+ <phrase role="identifier">X</phrase><phrase role="special">()</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="number">0</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="number">1</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="number">2</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="number">3</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="number">4</phrase>
+ <phrase role="identifier">fn</phrase><phrase role="special">():</phrase> <phrase role="number">5</phrase>
+ <phrase role="identifier">ctx</phrase> <phrase role="identifier">is</phrase> <phrase role="identifier">complete</phrase><phrase role="special">:</phrase> <phrase role="keyword">false</phrase>
+ <phrase role="identifier">call</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">.</phrase><phrase role="identifier">unwind_stack</phrase><phrase role="special">()</phrase>
+ <phrase role="special">~</phrase><phrase role="identifier">X</phrase><phrase role="special">()</phrase>
+ <phrase role="identifier">ctx</phrase> <phrase role="identifier">is</phrase> <phrase role="identifier">complete</phrase><phrase role="special">:</phrase> <phrase role="keyword">true</phrase>
+ <phrase role="identifier">Done</phrase>
+</programlisting>
+ <important>
+ <para>
+ You must not swallow <emphasis>forced_unwind</emphasis> exceptions!
+ </para>
+ </important>
+ <section id="context.context.context">
+ <title><link linkend="context.context.context">Class <code><phrase role="identifier">context</phrase></code></link></title>
+
+<programlisting><phrase role="preprocessor">#include</phrase> <phrase role="special"><</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">context</phrase><phrase role="special">/</phrase><phrase role="identifier">context</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">></phrase>
+
+<phrase role="keyword">class</phrase> <phrase role="identifier">context</phrase>
+<phrase role="special">{</phrase>
+<phrase role="keyword">public</phrase><phrase role="special">:</phrase>
+ <phrase role="identifier">context</phrase><phrase role="special">();</phrase>
+
+ <phrase role="keyword">template</phrase><phrase role="special"><</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase> <phrase role="special">></phrase>
+ <phrase role="identifier">context</phrase><phrase role="special">(</phrase> <phrase role="identifier">Fn</phrase> <phrase role="identifier">fn</phrase><phrase role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">size</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_unwind_t</phrase> <phrase role="identifier">do_unwind</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_return_t</phrase> <phrase role="identifier">do_return</phrase><phrase role="special">);</phrase>
+
+ <phrase role="keyword">template</phrase><phrase role="special"><</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Allocator</phrase> <phrase role="special">></phrase>
+ <phrase role="identifier">context</phrase><phrase role="special">(</phrase> <phrase role="identifier">Fn</phrase> <phrase role="identifier">fn</phrase><phrase role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">size</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_unwind_t</phrase> <phrase role="identifier">do_unwind</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_return_t</phrase> <phrase role="identifier">do_return</phrase><phrase role="special">,</phrase> <phrase role="identifier">Allocator</phrase> <phrase role="keyword">const</phrase><phrase role="special">&</phrase> <phrase role="identifier">alloc</phrase><phrase role="special">);</phrase>
+
+ <phrase role="keyword">template</phrase><phrase role="special"><</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase> <phrase role="special">></phrase>
+ <phrase role="identifier">context</phrase><phrase role="special">(</phrase> <phrase role="identifier">Fn</phrase> <phrase role="identifier">fn</phrase><phrase role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">size</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_unwind_t</phrase> <phrase role="identifier">do_unwind</phrase><phrase role="special">,</phrase> <phrase role="identifier">context</phrase> <phrase role="special">&</phrase> <phrase role="identifier">nxt</phrase><phrase role="special">);</phrase>
+
+ <phrase role="keyword">template</phrase><phrase role="special"><</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Allocator</phrase> <phrase role="special">></phrase>
+ <phrase role="identifier">context</phrase><phrase role="special">(</phrase> <phrase role="identifier">Fn</phrase> <phrase role="identifier">fn</phrase><phrase role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">size</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_unwind_t</phrase> <phrase role="identifier">do_unwind</phrase><phrase role="special">,</phrase> <phrase role="identifier">context</phrase> <phrase role="special">&</phrase> <phrase role="identifier">nxt</phrase><phrase role="special">,</phrase> <phrase role="identifier">Allocator</phrase> <phrase role="keyword">const</phrase><phrase role="special">&</phrase> <phrase role="identifier">alloc</phrase><phrase role="special">);</phrase>
+
+ <phrase role="keyword">template</phrase><phrase role="special"><</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">A0</phrase> <phrase role="special">></phrase>
+ <phrase role="identifier">context</phrase><phrase role="special">(</phrase> <phrase role="identifier">Fn</phrase> <phrase role="identifier">fn</phrase> <phrase role="identifier">A0</phrase> <phrase role="identifier">a0</phrase><phrase role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">size</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_unwind_t</phrase> <phrase role="identifier">do_unwind</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_return_t</phrase> <phrase role="identifier">do_return</phrase><phrase role="special">);</phrase>
+ <phrase role="special">...</phrase>
+ <phrase role="keyword">template</phrase><phrase role="special"><</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">A0</phrase><phrase role="special">,...,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">A9</phrase> <phrase role="special">></phrase>
+ <phrase role="identifier">context</phrase><phrase role="special">(</phrase> <phrase role="identifier">Fn</phrase> <phrase role="identifier">fn</phrase> <phrase role="identifier">A0</phrase> <phrase role="identifier">a0</phrase><phrase role="special">,...,</phrase> <phrase role="identifier">A9</phrase><phrase role="special">,</phrase> <phrase role="identifier">a9</phrase><phrase role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">size</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_unwind_t</phrase> <phrase role="identifier">do_unwind</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_return_t</phrase> <phrase role="identifier">do_return</phrase><phrase role="special">);</phrase>
+
+ <phrase role="keyword">template</phrase><phrase role="special"><</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Allocator</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">A0</phrase> <phrase role="special">></phrase>
+ <phrase role="identifier">context</phrase><phrase role="special">(</phrase> <phrase role="identifier">Fn</phrase> <phrase role="identifier">fn</phrase> <phrase role="identifier">A0</phrase> <phrase role="identifier">a0</phrase><phrase role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">size</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_unwind_t</phrase> <phrase role="identifier">do_unwind</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_return_t</phrase> <phrase role="identifier">do_return</phrase><phrase role="special">,</phrase> <phrase role="identifier">Allocator</phrase> <phrase role="keyword">const</phrase><phrase role="special">&</phrase> <phrase role="identifier">alloc</phrase><phrase role="special">);</phrase>
+ <phrase role="special">...</phrase>
+ <phrase role="keyword">template</phrase><phrase role="special"><</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Allocator</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">A0</phrase><phrase role="special">,...,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">A9</phrase> <phrase role="special">></phrase>
+ <phrase role="identifier">context</phrase><phrase role="special">(</phrase> <phrase role="identifier">Fn</phrase> <phrase role="identifier">fn</phrase> <phrase role="identifier">A0</phrase> <phrase role="identifier">a0</phrase><phrase role="special">,...,</phrase> <phrase role="identifier">A9</phrase><phrase role="special">,</phrase> <phrase role="identifier">a9</phrase><phrase role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">size</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_unwind_t</phrase> <phrase role="identifier">do_unwind</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_return_t</phrase> <phrase role="identifier">do_return</phrase><phrase role="special">,</phrase> <phrase role="identifier">Allocator</phrase> <phrase role="keyword">const</phrase><phrase role="special">&</phrase> <phrase role="identifier">alloc</phrase><phrase ro
le="special">);</phrase>
+
+ <phrase role="keyword">template</phrase><phrase role="special"><</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">A0</phrase> <phrase role="special">></phrase>
+ <phrase role="identifier">context</phrase><phrase role="special">(</phrase> <phrase role="identifier">Fn</phrase> <phrase role="identifier">fn</phrase> <phrase role="identifier">A0</phrase> <phrase role="identifier">a0</phrase><phrase role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">size</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_unwind_t</phrase> <phrase role="identifier">do_unwind</phrase><phrase role="special">,</phrase> <phrase role="identifier">context</phrase> <phrase role="special">&</phrase> <phrase role="identifier">nxt</phrase><phrase role="special">);</phrase>
+ <phrase role="special">...</phrase>
+ <phrase role="keyword">template</phrase><phrase role="special"><</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">A0</phrase><phrase role="special">,...,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">A9</phrase> <phrase role="special">></phrase>
+ <phrase role="identifier">context</phrase><phrase role="special">(</phrase> <phrase role="identifier">Fn</phrase> <phrase role="identifier">fn</phrase> <phrase role="identifier">A0</phrase> <phrase role="identifier">a0</phrase><phrase role="special">,...,</phrase> <phrase role="identifier">A9</phrase><phrase role="special">,</phrase> <phrase role="identifier">a9</phrase><phrase role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">size</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_unwind_t</phrase> <phrase role="identifier">do_unwind</phrase><phrase role="special">,</phrase> <phrase role="identifier">context</phrase> <phrase role="special">&</phrase> <phrase role="identifier">nxt</phrase><phrase role="special">);</phrase>
+
+ <phrase role="keyword">template</phrase><phrase role="special"><</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Allocator</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">A0</phrase> <phrase role="special">></phrase>
+ <phrase role="identifier">context</phrase><phrase role="special">(</phrase> <phrase role="identifier">Fn</phrase> <phrase role="identifier">fn</phrase> <phrase role="identifier">A0</phrase> <phrase role="identifier">a0</phrase><phrase role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">size</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_unwind_t</phrase> <phrase role="identifier">do_unwind</phrase><phrase role="special">,</phrase> <phrase role="identifier">context</phrase> <phrase role="special">&</phrase> <phrase role="identifier">nxt</phrase><phrase role="special">,</phrase> <phrase role="identifier">Allocator</phrase> <phrase role="keyword">const</phrase><phrase role="special">&</phrase> <phrase role="identifier">alloc</phrase><phrase role="special">);</phrase>
+ <phrase role="special">...</phrase>
+ <phrase role="keyword">template</phrase><phrase role="special"><</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Allocator</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">A0</phrase><phrase role="special">,...,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">A9</phrase> <phrase role="special">></phrase>
+ <phrase role="identifier">context</phrase><phrase role="special">(</phrase> <phrase role="identifier">Fn</phrase> <phrase role="identifier">fn</phrase> <phrase role="identifier">A0</phrase> <phrase role="identifier">a0</phrase><phrase role="special">,...,</phrase> <phrase role="identifier">A9</phrase><phrase role="special">,</phrase> <phrase role="identifier">a9</phrase><phrase role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">size</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_unwind_t</phrase> <phrase role="identifier">do_unwind</phrase><phrase role="special">,</phrase> <phrase role="identifier">context</phrase> <phrase role="special">&</phrase> <phrase role="identifier">nxt</phrase><phrase role="special">,</phrase> <phrase role="identifier">Allocator</phrase> <phrase role="keyword">const</phrase><phrase role="special">&</phrase> <phrase role="identifier
">alloc</phrase><phrase role="special">);</phrase>
+
+ <phrase role="keyword">template</phrase><phrase role="special"><</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase> <phrase role="special">></phrase>
+ <phrase role="identifier">context</phrase><phrase role="special">(</phrase> <phrase role="identifier">Fn</phrase> <phrase role="special">&&</phrase> <phrase role="identifier">fn</phrase><phrase role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">size</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_unwind_t</phrase> <phrase role="identifier">do_unwind</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_return_t</phrase> <phrase role="identifier">do_return</phrase><phrase role="special">);</phrase>
+
+ <phrase role="keyword">template</phrase><phrase role="special"><</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Allocator</phrase> <phrase role="special">></phrase>
+ <phrase role="identifier">context</phrase><phrase role="special">(</phrase> <phrase role="identifier">Fn</phrase> <phrase role="special">&&</phrase> <phrase role="identifier">fn</phrase><phrase role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">size</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_unwind_t</phrase> <phrase role="identifier">do_unwind</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_return_t</phrase> <phrase role="identifier">do_return</phrase><phrase role="special">,</phrase> <phrase role="identifier">Allocator</phrase> <phrase role="keyword">const</phrase><phrase role="special">&</phrase> <phrase role="identifier">alloc</phrase><phrase role="special">);</phrase>
+
+ <phrase role="keyword">template</phrase><phrase role="special"><</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase> <phrase role="special">></phrase>
+ <phrase role="identifier">context</phrase><phrase role="special">(</phrase> <phrase role="identifier">Fn</phrase> <phrase role="special">&&</phrase> <phrase role="identifier">fn</phrase><phrase role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">size</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_unwind_t</phrase> <phrase role="identifier">do_unwind</phrase><phrase role="special">,</phrase> <phrase role="identifier">context</phrase> <phrase role="special">&</phrase> <phrase role="identifier">nxt</phrase><phrase role="special">);</phrase>
+
+ <phrase role="keyword">template</phrase><phrase role="special"><</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase><phrase role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">Allocator</phrase> <phrase role="special">></phrase>
+ <phrase role="identifier">context</phrase><phrase role="special">(</phrase> <phrase role="identifier">Fn</phrase> <phrase role="special">&&</phrase> <phrase role="identifier">fn</phrase><phrase role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">size</phrase><phrase role="special">,</phrase> <phrase role="identifier">flag_unwind_t</phrase> <phrase role="identifier">do_unwind</phrase><phrase role="special">,</phrase> <phrase role="identifier">context</phrase> <phrase role="special">&</phrase> <phrase role="identifier">nxt</phrase><phrase role="special">,</phrase> <phrase role="identifier">Allocator</phrase> <phrase role="keyword">const</phrase><phrase role="special">&</phrase> <phrase role="identifier">alloc</phrase><phrase role="special">);</phrase>
+
+ <phrase role="special">~</phrase><phrase role="identifier">context</phrase><phrase role="special">();</phrase>
+
+ <phrase role="identifier">context</phrase><phrase role="special">(</phrase> <phrase role="identifier">context</phrase> <phrase role="special">&&</phrase> <phrase role="identifier">other</phrase><phrase role="special">);</phrase>
+
+ <phrase role="identifier">context</phrase> <phrase role="special">&</phrase> <phrase role="keyword">operator</phrase><phrase role="special">=(</phrase> <phrase role="identifier">context</phrase> <phrase role="special">&&</phrase> <phrase role="identifier">other</phrase><phrase role="special">);</phrase>
+
+ <phrase role="keyword">operator</phrase> <phrase role="identifier">unspecified</phrase><phrase role="special">-</phrase><phrase role="keyword">bool</phrase><phrase role="special">-</phrase><phrase role="identifier">type</phrase><phrase role="special">()</phrase> <phrase role="keyword">const</phrase><phrase role="special">;</phrase>
+
+ <phrase role="keyword">bool</phrase> <phrase role="keyword">operator</phrase><phrase role="special">!()</phrase> <phrase role="keyword">const</phrase><phrase role="special">;</phrase>
+
+ <phrase role="keyword">void</phrase> <phrase role="identifier">swap</phrase><phrase role="special">(</phrase> <phrase role="identifier">context</phrase> <phrase role="special">&</phrase> <phrase role="identifier">other</phrase><phrase role="special">);</phrase>
+
+ <phrase role="keyword">bool</phrase> <phrase role="identifier">is_complete</phrase><phrase role="special">()</phrase> <phrase role="keyword">const</phrase><phrase role="special">;</phrase>
+
+ <phrase role="keyword">bool</phrase> <phrase role="identifier">is_running</phrase><phrase role="special">()</phrase> <phrase role="keyword">const</phrase><phrase role="special">;</phrase>
+
+ <phrase role="identifier">intptr_t</phrase> <phrase role="identifier">start</phrase><phrase role="special">();</phrase>
+
+ <phrase role="identifier">intptr_t</phrase> <phrase role="identifier">resume</phrase><phrase role="special">(</phrase> <phrase role="identifier">intptr_t</phrase> <phrase role="identifier">vp</phrase> <phrase role="special">=</phrase> <phrase role="number">0</phrase><phrase role="special">);</phrase>
+
+ <phrase role="identifier">intptr_t</phrase> <phrase role="identifier">suspend</phrase><phrase role="special">(</phrase> <phrase role="identifier">intptr_t</phrase> <phrase role="identifier">vp</phrase> <phrase role="special">=</phrase> <phrase role="number">0</phrase><phrase role="special">);</phrase>
+
+ <phrase role="keyword">void</phrase> <phrase role="identifier">unwind_stack</phrase><phrase role="special">();</phrase>
+<phrase role="special">};</phrase>
+
+<phrase role="keyword">void</phrase> <phrase role="identifier">swap</phrase><phrase role="special">(</phrase> <phrase role="identifier">context</phrase> <phrase role="special">&</phrase> <phrase role="identifier">l</phrase><phrase role="special">,</phrase> <phrase role="identifier">context</phrase> <phrase role="special">&</phrase> <phrase role="identifier">r</phrase><phrase role="special">);</phrase>
+</programlisting>
+ <anchor id="context.context.context._code__phrase_role__identifier__context__phrase__phrase_role__special______phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.context.context._code__phrase_role__identifier__context__phrase__phrase_role__special______phrase___code_"><code><phrase
+ role="identifier">context</phrase><phrase role="special">()</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ Creates a context representing a <emphasis>not-a-context</emphasis>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ Nothing.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.context.context._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__fn__phrase___phrase_role__special___gt___phrase___phrase_role__identifier__context__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__size__phrase__phrase_role__special_____phrase___phrase_role__identifier__flag_unwind_t__phrase___phrase_role__identifier__do_unwind__phrase__phrase_role__special_____phrase___phrase_role__identifier__flag_return_t__phrase___phrase_role__identifier__do_return__phrase__phrase_role__special_____phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.context.context._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__fn__phrase___phrase_role__special___gt___phrase___phrase_role__identifier__context__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__size__phrase__phrase_role__special_____phrase___phrase_role__identifier__flag_unwind_t__phrase___phrase_role__identifier__do_unwind__phrase__phrase_role__special_____phrase___phrase_role__identifier__flag_return_t__phrase___phrase_role__identifier__do_return__phrase__phrase_role__special_____phrase___code_"><code><phrase
+ role="keyword">template</phrase><phrase role="special"><</phrase> <phrase
+ role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase> <phrase
+ role="special">></phrase> <phrase role="identifier">context</phrase><phrase
+ role="special">(</phrase> <phrase role="identifier">Fn</phrase> <phrase role="identifier">fn</phrase><phrase
+ role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase
+ role="identifier">size_t</phrase> <phrase role="identifier">size</phrase><phrase
+ role="special">,</phrase> <phrase role="identifier">flag_unwind_t</phrase>
+ <phrase role="identifier">do_unwind</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">flag_return_t</phrase> <phrase role="identifier">do_return</phrase><phrase
+ role="special">)</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Preconditions:</term>
+ <listitem>
+ <para>
+ <code><phrase role="identifier">size</phrase></code> > minimum_stacksize(),
+ <code><phrase role="identifier">size</phrase></code> < maximum_stacksize()
+ when ! is_stack_unbound().
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ Creates a context which will execute <code><phrase role="identifier">fn</phrase></code>.
+ If <code><phrase role="identifier">do_unwind</phrase></code> is <code><phrase
+ role="identifier">stack_unwind</phrase></code> the destructor of <code><phrase
+ role="special">*</phrase><phrase role="keyword">this</phrase></code>
+ unwinds the stack before destructing it. If <code><phrase role="identifier">do_return</phrase></code>
+ is <code><phrase role="identifier">exit_application</phrase></code>
+ the application exits with return code <code><phrase role="number">0</phrase></code>,
+ otherwise execution control is transfered back to the invoker (<code><phrase
+ role="identifier">resume</phrase><phrase role="special">()</phrase></code>
+ returns).
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ <emphasis>std::invalid_argument</emphasis> if a precondition is not
+ satisfied.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.context.context._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__allocator__phrase___phrase_role__special___gt___phrase___phrase_role__identifier__context__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__size__phrase__phrase_role__special_____phrase___phrase_role__identifier__flag_unwind_t__phrase___phrase_role__identifier__do_unwind__phrase__phrase_role__special_____phrase___phrase_role__identifier__flag_return_t__phrase___phrase_role__identifier__do_return__phrase__phrase_role__special_____phrase___phrase_role__identifier__allocator_
_phrase___phrase_role__keyword__const__phrase__phrase_role__special___amp___phrase___phrase_role__identifier__alloc__phrase__phrase_role__special_____phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.context.context._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__allocator__phrase___phrase_role__special___gt___phrase___phrase_role__identifier__context__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__size__phrase__phrase_role__special_____phrase___phrase_role__identifier__flag_unwind_t__phrase___phrase_role__identifier__do_unwind__phrase__phrase_role__special_____phrase___phrase_role__identifier__flag_return_t__phrase___phrase_role__identifier__do_return__phrase__phrase_role__special_____phrase___phrase_role__identifier__alloc
ator__phrase___phrase_role__keyword__const__phrase__phrase_role__special___amp___phrase___phrase_role__identifier__alloc__phrase__phrase_role__special_____phrase___code_"><code><phrase
+ role="keyword">template</phrase><phrase role="special"><</phrase> <phrase
+ role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase><phrase
+ role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase
+ role="identifier">Allocator</phrase> <phrase role="special">></phrase>
+ <phrase role="identifier">context</phrase><phrase role="special">(</phrase>
+ <phrase role="identifier">Fn</phrase> <phrase role="identifier">fn</phrase><phrase
+ role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase
+ role="identifier">size_t</phrase> <phrase role="identifier">size</phrase><phrase
+ role="special">,</phrase> <phrase role="identifier">flag_unwind_t</phrase>
+ <phrase role="identifier">do_unwind</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">flag_return_t</phrase> <phrase role="identifier">do_return</phrase><phrase
+ role="special">,</phrase> <phrase role="identifier">Allocator</phrase> <phrase
+ role="keyword">const</phrase><phrase role="special">&</phrase> <phrase
+ role="identifier">alloc</phrase><phrase role="special">)</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ Creates a context which will execute <code><phrase role="identifier">fn</phrase></code>.
+ If <code><phrase role="identifier">do_unwind</phrase></code> is <code><phrase
+ role="identifier">stack_unwind</phrase></code> the destructor of <code><phrase
+ role="special">*</phrase><phrase role="keyword">this</phrase></code>
+ unwinds the stack before destructing it. If <code><phrase role="identifier">do_return</phrase></code>
+ is <code><phrase role="identifier">exit_application</phrase></code>
+ the application exits with return code <code><phrase role="number">0</phrase></code>,
+ otherwise execution control is transfered back to the invoker (<code><phrase
+ role="identifier">resume</phrase><phrase role="special">()</phrase></code>
+ returns).
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ depends on <code><phrase role="identifier">alloc</phrase></code> if
+ a precondition is not satisfied.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.context.context._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__fn__phrase___phrase_role__special___gt___phrase___phrase_role__identifier__context__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__size__phrase__phrase_role__special_____phrase___phrase_role__identifier__flag_unwind_t__phrase___phrase_role__identifier__do_unwind__phrase__phrase_role__special_____phrase___phrase_role__identifier__context__phrase___phrase_role__special___amp___phrase___phrase_role__identifier__nxt__phrase__phrase_role__special_____phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.context.context._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__fn__phrase___phrase_role__special___gt___phrase___phrase_role__identifier__context__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__size__phrase__phrase_role__special_____phrase___phrase_role__identifier__flag_unwind_t__phrase___phrase_role__identifier__do_unwind__phrase__phrase_role__special_____phrase___phrase_role__identifier__context__phrase___phrase_role__special___amp___phrase___phrase_role__identifier__nxt__phrase__phrase_role__special_____phrase___code_"><code><phrase
+ role="keyword">template</phrase><phrase role="special"><</phrase> <phrase
+ role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase> <phrase
+ role="special">></phrase> <phrase role="identifier">context</phrase><phrase
+ role="special">(</phrase> <phrase role="identifier">Fn</phrase> <phrase role="identifier">fn</phrase><phrase
+ role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase
+ role="identifier">size_t</phrase> <phrase role="identifier">size</phrase><phrase
+ role="special">,</phrase> <phrase role="identifier">flag_unwind_t</phrase>
+ <phrase role="identifier">do_unwind</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">context</phrase> <phrase role="special">&</phrase>
+ <phrase role="identifier">nxt</phrase><phrase role="special">)</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Preconditions:</term>
+ <listitem>
+ <para>
+ <code><phrase role="identifier">size</phrase></code> > minimum_stacksize(),
+ <code><phrase role="identifier">size</phrase></code> < maximum_stacksize()
+ when ! is_stack_unbound(), <code><phrase role="identifier">nxt</phrase></code>
+ is not a <emphasis>not-a-context</emphasis>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ Creates a context which will execute <code><phrase role="identifier">fn</phrase></code>.
+ If <code><phrase role="identifier">do_unwind</phrase></code> is <code><phrase
+ role="identifier">stack_unwind</phrase></code> the destructor of <code><phrase
+ role="special">*</phrase><phrase role="keyword">this</phrase></code>
+ unwinds the stack before destructing it. execution control is transfered
+ to <code><phrase role="identifier">nxt</phrase></code> if <code><phrase
+ role="identifier">fn</phrase></code> returns (<code><phrase role="identifier">nxt</phrase></code>
+ is linked).
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ <emphasis>std::invalid_argument</emphasis> if a precondition is not
+ satisfied.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.context.context._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__allocator__phrase___phrase_role__special___gt___phrase___phrase_role__identifier__context__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__size__phrase__phrase_role__special_____phrase___phrase_role__identifier__flag_unwind_t__phrase___phrase_role__identifier__do_unwind__phrase__phrase_role__special_____phrase___phrase_role__identifier__context__phrase___phrase_role__special___amp___phrase___phrase_role__identifier__nxt__phrase__phrase_role__special_____phrase___phrase_ro
le__identifier__allocatorconst__phrase__phrase_role__special___amp___phrase___phrase_role__identifier__alloc__phrase__phrase_role__special_____phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.context.context._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__allocator__phrase___phrase_role__special___gt___phrase___phrase_role__identifier__context__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__size__phrase__phrase_role__special_____phrase___phrase_role__identifier__flag_unwind_t__phrase___phrase_role__identifier__do_unwind__phrase__phrase_role__special_____phrase___phrase_role__identifier__context__phrase___phrase_role__special___amp___phrase___phrase_role__identifier__nxt__phrase__phrase_role__special_____phrase___phra
se_role__identifier__allocatorconst__phrase__phrase_role__special___amp___phrase___phrase_role__identifier__alloc__phrase__phrase_role__special_____phrase___code_"><code><phrase
+ role="keyword">template</phrase><phrase role="special"><</phrase> <phrase
+ role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase><phrase
+ role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase
+ role="identifier">Allocator</phrase> <phrase role="special">></phrase>
+ <phrase role="identifier">context</phrase><phrase role="special">(</phrase>
+ <phrase role="identifier">Fn</phrase> <phrase role="identifier">fn</phrase><phrase
+ role="special">,</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase
+ role="identifier">size_t</phrase> <phrase role="identifier">size</phrase><phrase
+ role="special">,</phrase> <phrase role="identifier">flag_unwind_t</phrase>
+ <phrase role="identifier">do_unwind</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">context</phrase> <phrase role="special">&</phrase>
+ <phrase role="identifier">nxt</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">Allocatorconst</phrase><phrase role="special">&</phrase>
+ <phrase role="identifier">alloc</phrase><phrase role="special">)</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Preconditions:</term>
+ <listitem>
+ <para>
+ <code><phrase role="identifier">nxt</phrase></code> is not a <emphasis>not-a-context</emphasis>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ Creates a context which will execute <code><phrase role="identifier">fn</phrase></code>.
+ If <code><phrase role="identifier">do_unwind</phrase></code> is <code><phrase
+ role="identifier">stack_unwind</phrase></code> the destructor of <code><phrase
+ role="special">*</phrase><phrase role="keyword">this</phrase></code>
+ unwinds the stack before destructing it. execution control is transfered
+ to <code><phrase role="identifier">nxt</phrase></code> if <code><phrase
+ role="identifier">fn</phrase></code> returns (<code><phrase role="identifier">nxt</phrase></code>
+ is linked).
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ depends on <code><phrase role="identifier">alloc</phrase></code> if
+ a precondition is not satisfied.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.context.context._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__a0__phrase__phrase_role__special________phrase___phrase_role__special___gt___phrase___phrase_role__identifier__context__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__identifier__a0__phrase___phrase_role__identifier__a0__phrase__phrase_role__special_________phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__size__phrase__phrase_role__special_____phrase___phrase_role__identifier__flag_unwind_t__phrase___phrase_role__identifier__do_unwind__phrase__phrase_role__special_____phrase___phrase_role__identif
ier__flag_return_t__phrase___phrase_role__identifier__do_return__phrase__phrase_role__special_____phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.context.context._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__a0__phrase__phrase_role__special________phrase___phrase_role__special___gt___phrase___phrase_role__identifier__context__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__identifier__a0__phrase___phrase_role__identifier__a0__phrase__phrase_role__special_________phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__size__phrase__phrase_role__special_____phrase___phrase_role__identifier__flag_unwind_t__phrase___phrase_role__identifier__do_unwind__phrase__phrase_role__special_____phrase___phrase_role__id
entifier__flag_return_t__phrase___phrase_role__identifier__do_return__phrase__phrase_role__special_____phrase___code_"><code><phrase
+ role="keyword">template</phrase><phrase role="special"><</phrase> <phrase
+ role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase><phrase
+ role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase
+ role="identifier">A0</phrase><phrase role="special">,...</phrase> <phrase
+ role="special">></phrase> <phrase role="identifier">context</phrase><phrase
+ role="special">(</phrase> <phrase role="identifier">Fn</phrase> <phrase role="identifier">fn</phrase><phrase
+ role="special">,</phrase> <phrase role="identifier">A0</phrase> <phrase role="identifier">a0</phrase><phrase
+ role="special">,...,</phrase> <phrase role="identifier">std</phrase><phrase
+ role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase
+ role="identifier">size</phrase><phrase role="special">,</phrase> <phrase
+ role="identifier">flag_unwind_t</phrase> <phrase role="identifier">do_unwind</phrase><phrase
+ role="special">,</phrase> <phrase role="identifier">flag_return_t</phrase>
+ <phrase role="identifier">do_return</phrase><phrase role="special">)</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Preconditions:</term>
+ <listitem>
+ <para>
+ <code><phrase role="identifier">size</phrase></code> > minimum_stacksize(),
+ <code><phrase role="identifier">size</phrase></code> < maximum_stacksize()
+ when ! is_stack_unbound().
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ Creates a context which will execute <code><phrase role="identifier">fn</phrase></code>
+ (arguments <code><phrase role="identifier">A0</phrase></code>,... are
+ bound to <code><phrase role="identifier">fn</phrase></code>). If <code><phrase
+ role="identifier">do_unwind</phrase></code> is <code><phrase role="identifier">stack_unwind</phrase></code>
+ the destructor of <code><phrase role="special">*</phrase><phrase role="keyword">this</phrase></code>
+ unwinds the stack before destructing it. If <code><phrase role="identifier">do_return</phrase></code>
+ is <code><phrase role="identifier">exit_application</phrase></code>
+ the application exits with return code <code><phrase role="number">0</phrase></code>,
+ otherwise execution control is transfered back to the invoker (<code><phrase
+ role="identifier">resume</phrase><phrase role="special">()</phrase></code>
+ returns).
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ <emphasis>std::invalid_argument</emphasis> if a precondition is not
+ satisfied.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.context.context._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__allocator__phrase__phrase_role__special_____phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__a0__phrase__phrase_role__special________phrase___phrase_role__special___gt___phrase___phrase_role__identifier__context__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__identifier__a0__phrase___phrase_role__identifier__a0__phrase__phrase_role__special_________phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__size__phrase__phrase_role__special_____phrase___phrase_role__identifier__fla
g_unwind_t__phrase___phrase_role__identifier__do_unwind__phrase__phrase_role__special_____phrase___phrase_role__identifier__flag_return_t__phrase___phrase_role__identifier__do_return__phrase__phrase_role__special_____phrase___phrase_role__identifier__allocator__phrase___phrase_role__keyword__const__phrase__phrase_role__special___amp___phrase___phrase_role__identifier__alloc__phrase__phrase_role__special_____phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.context.context._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__allocator__phrase__phrase_role__special_____phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__a0__phrase__phrase_role__special________phrase___phrase_role__special___gt___phrase___phrase_role__identifier__context__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__identifier__a0__phrase___phrase_role__identifier__a0__phrase__phrase_role__special_________phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__size__phrase__phrase_role__special_____phrase___phrase_role__identifier
__flag_unwind_t__phrase___phrase_role__identifier__do_unwind__phrase__phrase_role__special_____phrase___phrase_role__identifier__flag_return_t__phrase___phrase_role__identifier__do_return__phrase__phrase_role__special_____phrase___phrase_role__identifier__allocator__phrase___phrase_role__keyword__const__phrase__phrase_role__special___amp___phrase___phrase_role__identifier__alloc__phrase__phrase_role__special_____phrase___code_"><code><phrase
+ role="keyword">template</phrase><phrase role="special"><</phrase> <phrase
+ role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase><phrase
+ role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase
+ role="identifier">Allocator</phrase><phrase role="special">,</phrase> <phrase
+ role="keyword">typename</phrase> <phrase role="identifier">A0</phrase><phrase
+ role="special">,...</phrase> <phrase role="special">></phrase> <phrase
+ role="identifier">context</phrase><phrase role="special">(</phrase> <phrase
+ role="identifier">Fn</phrase> <phrase role="identifier">fn</phrase><phrase
+ role="special">,</phrase> <phrase role="identifier">A0</phrase> <phrase role="identifier">a0</phrase><phrase
+ role="special">,...,</phrase> <phrase role="identifier">std</phrase><phrase
+ role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase
+ role="identifier">size</phrase><phrase role="special">,</phrase> <phrase
+ role="identifier">flag_unwind_t</phrase> <phrase role="identifier">do_unwind</phrase><phrase
+ role="special">,</phrase> <phrase role="identifier">flag_return_t</phrase>
+ <phrase role="identifier">do_return</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">Allocator</phrase> <phrase role="keyword">const</phrase><phrase
+ role="special">&</phrase> <phrase role="identifier">alloc</phrase><phrase
+ role="special">)</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Preconditions:</term>
+ <listitem>
+ <para>
+ <code><phrase role="identifier">size</phrase></code> > minimum_stacksize(),
+ <code><phrase role="identifier">size</phrase></code> < maximum_stacksize()
+ when ! is_stack_unbound().
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ Creates a context which will execute <code><phrase role="identifier">fn</phrase></code>
+ (arguments <code><phrase role="identifier">A0</phrase></code>,... are
+ bound to <code><phrase role="identifier">fn</phrase></code>). If <code><phrase
+ role="identifier">do_unwind</phrase></code> is <code><phrase role="identifier">stack_unwind</phrase></code>
+ the destructor of <code><phrase role="special">*</phrase><phrase role="keyword">this</phrase></code>
+ unwinds the stack before destructing it. If <code><phrase role="identifier">do_return</phrase></code>
+ is <code><phrase role="identifier">exit_application</phrase></code>
+ the application exits with return code <code><phrase role="number">0</phrase></code>,
+ otherwise execution control is transfered back to the invoker (<code><phrase
+ role="identifier">resume</phrase><phrase role="special">()</phrase></code>
+ returns).
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ depends on <code><phrase role="identifier">alloc</phrase></code> if
+ a precondition is not satisfied.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.context.context._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__a0__phrase__phrase_role__special________phrase___phrase_role__special___gt___phrase___phrase_role__identifier__context__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__identifier__a0__phrase___phrase_role__identifier__a0__phrase__phrase_role__special_________phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__size__phrase__phrase_role__special_____phrase___phrase_role__identifier__flag_unwind_t__phrase___phrase_role__identifier__do_unwind__phrase__phrase_role__special_____phrase___phrase_role__identif
ier__context__phrase___phrase_role__special___amp___phrase___phrase_role__identifier__nxt__phrase__phrase_role__special_____phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.context.context._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__a0__phrase__phrase_role__special________phrase___phrase_role__special___gt___phrase___phrase_role__identifier__context__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__identifier__a0__phrase___phrase_role__identifier__a0__phrase__phrase_role__special_________phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__size__phrase__phrase_role__special_____phrase___phrase_role__identifier__flag_unwind_t__phrase___phrase_role__identifier__do_unwind__phrase__phrase_role__special_____phrase___phrase_role__id
entifier__context__phrase___phrase_role__special___amp___phrase___phrase_role__identifier__nxt__phrase__phrase_role__special_____phrase___code_"><code><phrase
+ role="keyword">template</phrase><phrase role="special"><</phrase> <phrase
+ role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase><phrase
+ role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase
+ role="identifier">A0</phrase><phrase role="special">,...</phrase> <phrase
+ role="special">></phrase> <phrase role="identifier">context</phrase><phrase
+ role="special">(</phrase> <phrase role="identifier">Fn</phrase> <phrase role="identifier">fn</phrase><phrase
+ role="special">,</phrase> <phrase role="identifier">A0</phrase> <phrase role="identifier">a0</phrase><phrase
+ role="special">,...,</phrase> <phrase role="identifier">std</phrase><phrase
+ role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase
+ role="identifier">size</phrase><phrase role="special">,</phrase> <phrase
+ role="identifier">flag_unwind_t</phrase> <phrase role="identifier">do_unwind</phrase><phrase
+ role="special">,</phrase> <phrase role="identifier">context</phrase> <phrase
+ role="special">&</phrase> <phrase role="identifier">nxt</phrase><phrase
+ role="special">)</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Preconditions:</term>
+ <listitem>
+ <para>
+ <code><phrase role="identifier">size</phrase></code> > minimum_stacksize(),
+ <code><phrase role="identifier">size</phrase></code> < maximum_stacksize()
+ when ! is_stack_unbound(), <code><phrase role="identifier">nxt</phrase></code>
+ is not a <emphasis>not-a-context</emphasis>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ Creates a context which will execute <code><phrase role="identifier">fn</phrase></code>
+ (arguments<code><phrase role="identifier">A0</phrase></code>,... are
+ bound to <code><phrase role="identifier">fn</phrase></code>). If <code><phrase
+ role="identifier">do_unwind</phrase></code> is <code><phrase role="identifier">stack_unwind</phrase></code>
+ the destructor of <code><phrase role="special">*</phrase><phrase role="keyword">this</phrase></code>
+ unwinds the stack before destructing it. execution control is transfered
+ to <code><phrase role="identifier">nxt</phrase></code> if <code><phrase
+ role="identifier">fn</phrase></code> returns (<code><phrase role="identifier">nxt</phrase></code>
+ is linked).
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ <emphasis>std::invalid_argument</emphasis> if a precondition is not
+ satisfied.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.context.context._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__allocator__phrase__phrase_role__special_____phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__a0__phrase__phrase_role__special________phrase___phrase_role__special___gt___phrase___phrase_role__identifier__context__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__identifier__a0__phrase___phrase_role__identifier__a0__phrase__phrase_role__special_________phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__size__phrase__phrase_role__special_____phrase___phrase_role__identifier__fla
g_unwind_t__phrase___phrase_role__identifier__do_unwind__phrase__phrase_role__special_____phrase___phrase_role__identifier__context__phrase___phrase_role__special___amp___phrase___phrase_role__identifier__nxt__phrase__phrase_role__special_____phrase___phrase_role__identifier__allocator__phrase___phrase_role__keyword__const__phrase__phrase_role__special___amp___phrase___phrase_role__identifier__alloc__phrase__phrase_role__special_____phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.context.context._code__phrase_role__keyword__template__phrase__phrase_role__special___lt___phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__allocator__phrase__phrase_role__special_____phrase___phrase_role__keyword__typename__phrase___phrase_role__identifier__a0__phrase__phrase_role__special________phrase___phrase_role__special___gt___phrase___phrase_role__identifier__context__phrase__phrase_role__special_____phrase___phrase_role__identifier__fn__phrase___phrase_role__identifier__fn__phrase__phrase_role__special_____phrase___phrase_role__identifier__a0__phrase___phrase_role__identifier__a0__phrase__phrase_role__special_________phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__size__phrase__phrase_role__special_____phrase___phrase_role__identifier
__flag_unwind_t__phrase___phrase_role__identifier__do_unwind__phrase__phrase_role__special_____phrase___phrase_role__identifier__context__phrase___phrase_role__special___amp___phrase___phrase_role__identifier__nxt__phrase__phrase_role__special_____phrase___phrase_role__identifier__allocator__phrase___phrase_role__keyword__const__phrase__phrase_role__special___amp___phrase___phrase_role__identifier__alloc__phrase__phrase_role__special_____phrase___code_"><code><phrase
+ role="keyword">template</phrase><phrase role="special"><</phrase> <phrase
+ role="keyword">typename</phrase> <phrase role="identifier">Fn</phrase><phrase
+ role="special">,</phrase> <phrase role="keyword">typename</phrase> <phrase
+ role="identifier">Allocator</phrase><phrase role="special">,</phrase> <phrase
+ role="keyword">typename</phrase> <phrase role="identifier">A0</phrase><phrase
+ role="special">,...</phrase> <phrase role="special">></phrase> <phrase
+ role="identifier">context</phrase><phrase role="special">(</phrase> <phrase
+ role="identifier">Fn</phrase> <phrase role="identifier">fn</phrase><phrase
+ role="special">,</phrase> <phrase role="identifier">A0</phrase> <phrase role="identifier">a0</phrase><phrase
+ role="special">,...,</phrase> <phrase role="identifier">std</phrase><phrase
+ role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase
+ role="identifier">size</phrase><phrase role="special">,</phrase> <phrase
+ role="identifier">flag_unwind_t</phrase> <phrase role="identifier">do_unwind</phrase><phrase
+ role="special">,</phrase> <phrase role="identifier">context</phrase> <phrase
+ role="special">&</phrase> <phrase role="identifier">nxt</phrase><phrase
+ role="special">,</phrase> <phrase role="identifier">Allocator</phrase> <phrase
+ role="keyword">const</phrase><phrase role="special">&</phrase> <phrase
+ role="identifier">alloc</phrase><phrase role="special">)</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Preconditions:</term>
+ <listitem>
+ <para>
+ <code><phrase role="identifier">nxt</phrase></code> is not a <emphasis>not-a-context</emphasis>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ Creates a context which will execute <code><phrase role="identifier">fn</phrase></code>
+ (arguments<code><phrase role="identifier">A0</phrase></code>,... are
+ bound to <code><phrase role="identifier">fn</phrase></code>). If <code><phrase
+ role="identifier">do_unwind</phrase></code> is <code><phrase role="identifier">stack_unwind</phrase></code>
+ the destructor of <code><phrase role="special">*</phrase><phrase role="keyword">this</phrase></code>
+ unwinds the stack before destructing it. execution control is transfered
+ to <code><phrase role="identifier">nxt</phrase></code> if <code><phrase
+ role="identifier">fn</phrase></code> returns (<code><phrase role="identifier">nxt</phrase></code>
+ is linked).
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ depends on <code><phrase role="identifier">alloc</phrase></code> if
+ a precondition is not satisfied.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.context.context._code__phrase_role__special_____phrase__phrase_role__identifier__context__phrase__phrase_role__special______phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.context.context._code__phrase_role__special_____phrase__phrase_role__identifier__context__phrase__phrase_role__special______phrase___code_"><code><phrase
+ role="special">~</phrase><phrase role="identifier">context</phrase><phrase
+ role="special">()</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ Destroys the instance and deallocates the stack. Unwinds the stack
+ if it was specified in the constructor of <code><phrase role="special">*</phrase><phrase
+ role="keyword">this</phrase></code>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ Nothing.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.context.context._code__phrase_role__identifier__context__phrase__phrase_role__special_____phrase___phrase_role__identifier__context__phrase___phrase_role__special___amp__amp___phrase___phrase_role__identifier__other__phrase__phrase_role__special_____phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.context.context._code__phrase_role__identifier__context__phrase__phrase_role__special_____phrase___phrase_role__identifier__context__phrase___phrase_role__special___amp__amp___phrase___phrase_role__identifier__other__phrase__phrase_role__special_____phrase___code_"><code><phrase
+ role="identifier">context</phrase><phrase role="special">(</phrase> <phrase
+ role="identifier">context</phrase> <phrase role="special">&&</phrase>
+ <phrase role="identifier">other</phrase><phrase role="special">)</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ Moves the internal data of <code><phrase role="identifier">other</phrase></code>
+ to <code><phrase role="special">*</phrase><phrase role="keyword">this</phrase></code>.
+ <code><phrase role="identifier">other</phrase></code> becomes <emphasis>not-a-context</emphasis>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ Nothing.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.context.context._code__phrase_role__identifier__context__phrase___phrase_role__special___amp___phrase___phrase_role__keyword__operator__phrase__phrase_role__special______phrase___phrase_role__identifier__context__phrase___phrase_role__special___amp__amp___phrase___phrase_role__identifier__other__phrase__phrase_role__special_____phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.context.context._code__phrase_role__identifier__context__phrase___phrase_role__special___amp___phrase___phrase_role__keyword__operator__phrase__phrase_role__special______phrase___phrase_role__identifier__context__phrase___phrase_role__special___amp__amp___phrase___phrase_role__identifier__other__phrase__phrase_role__special_____phrase___code_"><code><phrase
+ role="identifier">context</phrase> <phrase role="special">&</phrase>
+ <phrase role="keyword">operator</phrase><phrase role="special">=(</phrase>
+ <phrase role="identifier">context</phrase> <phrase role="special">&&</phrase>
+ <phrase role="identifier">other</phrase><phrase role="special">)</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ Destroys the internal data of <code><phrase role="special">*</phrase><phrase
+ role="keyword">this</phrase></code> and moves the internal data of
+ <code><phrase role="identifier">other</phrase></code> to <code><phrase
+ role="special">*</phrase><phrase role="keyword">this</phrase></code>.
+ <code><phrase role="identifier">other</phrase></code> becomes <emphasis>not-a-context</emphasis>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ Nothing.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.context.context._code__phrase_role__keyword__operator__phrase___phrase_role__identifier__unspecified__phrase__phrase_role__special_____phrase__phrase_role__keyword__bool__phrase__phrase_role__special_____phrase__phrase_role__identifier__type__phrase__phrase_role__special______phrase___phrase_role__keyword__const__phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.context.context._code__phrase_role__keyword__operator__phrase___phrase_role__identifier__unspecified__phrase__phrase_role__special_____phrase__phrase_role__keyword__bool__phrase__phrase_role__special_____phrase__phrase_role__identifier__type__phrase__phrase_role__special______phrase___phrase_role__keyword__const__phrase___code_"><code><phrase
+ role="keyword">operator</phrase> <phrase role="identifier">unspecified</phrase><phrase
+ role="special">-</phrase><phrase role="keyword">bool</phrase><phrase role="special">-</phrase><phrase
+ role="identifier">type</phrase><phrase role="special">()</phrase> <phrase
+ role="keyword">const</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Returns:</term>
+ <listitem>
+ <para>
+ If <code><phrase role="special">*</phrase><phrase role="keyword">this</phrase></code>
+ refers to <emphasis>not-a-context</emphasis>, the function returns
+ false. Otherwise true.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ Nothing.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.context.context._code__phrase_role__keyword__bool__phrase___phrase_role__keyword__operator__phrase__phrase_role__special_______phrase___phrase_role__keyword__const__phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.context.context._code__phrase_role__keyword__bool__phrase___phrase_role__keyword__operator__phrase__phrase_role__special_______phrase___phrase_role__keyword__const__phrase___code_"><code><phrase
+ role="keyword">bool</phrase> <phrase role="keyword">operator</phrase><phrase
+ role="special">!()</phrase> <phrase role="keyword">const</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Returns:</term>
+ <listitem>
+ <para>
+ If <code><phrase role="special">*</phrase><phrase role="keyword">this</phrase></code>
+ refers not to <emphasis>not-a-context</emphasis>, the function returns
+ true. Otherwise false.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ Nothing.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.context.context._code__phrase_role__keyword__void__phrase___phrase_role__identifier__swap__phrase__phrase_role__special_____phrase___phrase_role__identifier__context__phrase___phrase_role__special___amp___phrase___phrase_role__identifier__other__phrase__phrase_role__special_____phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.context.context._code__phrase_role__keyword__void__phrase___phrase_role__identifier__swap__phrase__phrase_role__special_____phrase___phrase_role__identifier__context__phrase___phrase_role__special___amp___phrase___phrase_role__identifier__other__phrase__phrase_role__special_____phrase___code_"><code><phrase
+ role="keyword">void</phrase> <phrase role="identifier">swap</phrase><phrase
+ role="special">(</phrase> <phrase role="identifier">context</phrase> <phrase
+ role="special">&</phrase> <phrase role="identifier">other</phrase><phrase
+ role="special">)</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ Swaps the internal data from <code><phrase role="special">*</phrase><phrase
+ role="keyword">this</phrase></code> with the values of <code><phrase
+ role="identifier">other</phrase></code>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ Nothing.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.context.context._code__phrase_role__keyword__bool__phrase___phrase_role__identifier__is_complete__phrase__phrase_role__special______phrase___phrase_role__keyword__const__phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.context.context._code__phrase_role__keyword__bool__phrase___phrase_role__identifier__is_complete__phrase__phrase_role__special______phrase___phrase_role__keyword__const__phrase___code_"><code><phrase
+ role="keyword">bool</phrase> <phrase role="identifier">is_complete</phrase><phrase
+ role="special">()</phrase> <phrase role="keyword">const</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Preconditions:</term>
+ <listitem>
+ <para>
+ <code><phrase role="special">*</phrase><phrase role="keyword">this</phrase></code>
+ is not a <emphasis>not-a-context</emphasis>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ Returns <code><phrase role="keyword">true</phrase></code> if context-function
+ of <code><phrase role="special">*</phrase><phrase role="keyword">this</phrase></code>
+ has returned.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ Nothing.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.context.context._code__phrase_role__keyword__bool__phrase___phrase_role__identifier__is_running__phrase__phrase_role__special______phrase___phrase_role__keyword__const__phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.context.context._code__phrase_role__keyword__bool__phrase___phrase_role__identifier__is_running__phrase__phrase_role__special______phrase___phrase_role__keyword__const__phrase___code_"><code><phrase
+ role="keyword">bool</phrase> <phrase role="identifier">is_running</phrase><phrase
+ role="special">()</phrase> <phrase role="keyword">const</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Preconditions:</term>
+ <listitem>
+ <para>
+ <code><phrase role="special">*</phrase><phrase role="keyword">this</phrase></code>
+ is not a <emphasis>not-a-context</emphasis>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ Returns <code><phrase role="keyword">true</phrase></code> if <code><phrase
+ role="special">*</phrase><phrase role="keyword">this</phrase></code>
+ is the currently active context.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ Nothing.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.context.context._code__phrase_role__identifier__intptr_t__phrase___phrase_role__identifier__start__phrase__phrase_role__special______phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.context.context._code__phrase_role__identifier__intptr_t__phrase___phrase_role__identifier__start__phrase__phrase_role__special______phrase___code_"><code><phrase
+ role="identifier">intptr_t</phrase> <phrase role="identifier">start</phrase><phrase
+ role="special">()</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Preconditions:</term>
+ <listitem>
+ <para>
+ <code><phrase role="special">*</phrase><phrase role="keyword">this</phrase></code>
+ is not a <emphasis>not-a-context</emphasis>, <code><phrase role="special">!</phrase>
+ <phrase role="identifier">is_complete</phrase><phrase role="special">()</phrase></code>
+ and <code><phrase role="special">!</phrase> <phrase role="identifier">is_running</phrase><phrase
+ role="special">()</phrase></code>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ <code><phrase role="identifier">start</phrase><phrase role="special">()</phrase></code>
+ enters the <emphasis>context-function</emphasis> <code><phrase role="identifier">fn</phrase></code>
+ with which the context was constructed. Upon return, the context was
+ either left via <code><phrase role="identifier">suspend</phrase><phrase
+ role="special">()</phrase></code> or the <emphasis>context-function</emphasis>
+ returned.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Returns:</term>
+ <listitem>
+ <para>
+ A intptr_t passed to <code><phrase role="identifier">suspend</phrase><phrase
+ role="special">()</phrase></code> is returned if the context was left
+ with <code><phrase role="identifier">suspend</phrase><phrase role="special">()</phrase></code>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ Nothing.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.context.context._code__phrase_role__identifier__intptr_t__phrase___phrase_role__identifier__resume__phrase__phrase_role__special_____phrase___phrase_role__identifier__intptr_t__phrase___phrase_role__identifier__vp__phrase___phrase_role__special_____phrase___phrase_role__number__0__phrase__phrase_role__special_____phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.context.context._code__phrase_role__identifier__intptr_t__phrase___phrase_role__identifier__resume__phrase__phrase_role__special_____phrase___phrase_role__identifier__intptr_t__phrase___phrase_role__identifier__vp__phrase___phrase_role__special_____phrase___phrase_role__number__0__phrase__phrase_role__special_____phrase___code_"><code><phrase
+ role="identifier">intptr_t</phrase> <phrase role="identifier">resume</phrase><phrase
+ role="special">(</phrase> <phrase role="identifier">intptr_t</phrase> <phrase
+ role="identifier">vp</phrase> <phrase role="special">=</phrase> <phrase role="number">0</phrase><phrase
+ role="special">)</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Preconditions:</term>
+ <listitem>
+ <para>
+ <code><phrase role="special">*</phrase><phrase role="keyword">this</phrase></code>
+ is not a <emphasis>not-a-context</emphasis>, <code><phrase role="special">!</phrase>
+ <phrase role="identifier">is_complete</phrase><phrase role="special">()</phrase></code>
+ and <code><phrase role="special">!</phrase> <phrase role="identifier">is_running</phrase><phrase
+ role="special">()</phrase></code>, <code><phrase role="identifier">start</phrase><phrase
+ role="special">()</phrase></code> was called before.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ None, if *this was not suspended by a previous call to suspend(). Otherwise,
+ execution control is transferred back to the caller of suspend(), thereby
+ resuming *this. The argument, vp, will be returned by the previous
+ call to suspend().
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ Nothing.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.context.context._code__phrase_role__identifier__intptr_t__phrase___phrase_role__identifier__suspend__phrase__phrase_role__special_____phrase___phrase_role__identifier__intptr_t__phrase___phrase_role__identifier__vp__phrase___phrase_role__special_____phrase___phrase_role__number__0__phrase__phrase_role__special_____phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.context.context._code__phrase_role__identifier__intptr_t__phrase___phrase_role__identifier__suspend__phrase__phrase_role__special_____phrase___phrase_role__identifier__intptr_t__phrase___phrase_role__identifier__vp__phrase___phrase_role__special_____phrase___phrase_role__number__0__phrase__phrase_role__special_____phrase___code_"><code><phrase
+ role="identifier">intptr_t</phrase> <phrase role="identifier">suspend</phrase><phrase
+ role="special">(</phrase> <phrase role="identifier">intptr_t</phrase> <phrase
+ role="identifier">vp</phrase> <phrase role="special">=</phrase> <phrase role="number">0</phrase><phrase
+ role="special">)</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Preconditions:</term>
+ <listitem>
+ <para>
+ <code><phrase role="special">*</phrase><phrase role="keyword">this</phrase></code>
+ is not a <emphasis>not-a-context</emphasis>, <code><phrase role="special">!</phrase>
+ <phrase role="identifier">is_complete</phrase><phrase role="special">()</phrase></code>
+ and <code><phrase role="identifier">is_running</phrase><phrase role="special">()</phrase></code>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ Transfers execution control to the caller of the most recent call to
+ start() or resume(). The argument, vp, will be returned by start()
+ or resume().
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ <emphasis>forced_unwind</emphasis> if <emphasis>context::unwind_stack()</emphasis>
+ was called.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.context.context._code__phrase_role__keyword__void__phrase___phrase_role__identifier__unwind_stack__phrase__phrase_role__special______phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.context.context._code__phrase_role__keyword__void__phrase___phrase_role__identifier__unwind_stack__phrase__phrase_role__special______phrase___code_"><code><phrase
+ role="keyword">void</phrase> <phrase role="identifier">unwind_stack</phrase><phrase
+ role="special">()</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Preconditions:</term>
+ <listitem>
+ <para>
+ <code><phrase role="special">*</phrase><phrase role="keyword">this</phrase></code>
+ is not a <emphasis>not-a-context</emphasis>, <code><phrase role="special">!</phrase>
+ <phrase role="identifier">is_complete</phrase><phrase role="special">()</phrase></code>
+ and <code><phrase role="special">!</phrase> <phrase role="identifier">is_running</phrase><phrase
+ role="special">()</phrase></code>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ Destroys all objects allocated on the stack, owned by *this, in the
+ reverse order of their allocation.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ Nothing.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Postconditions:</term>
+ <listitem>
+ <para>
+ <code><phrase role="special">*</phrase><phrase role="keyword">this</phrase></code>
+ is not a <emphasis>not-a-context</emphasis> and <code><phrase role="identifier">is_complete</phrase><phrase
+ role="special">()</phrase></code>.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.context.context.non_member_function__code__phrase_role__identifier__swap__phrase__phrase_role__special______phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.context.context.non_member_function__code__phrase_role__identifier__swap__phrase__phrase_role__special______phrase___code_">Non-member
+ function <code><phrase role="identifier">swap</phrase><phrase role="special">()</phrase></code></link>
+ </bridgehead>
+
+<programlisting><phrase role="keyword">void</phrase> <phrase role="identifier">swap</phrase><phrase role="special">(</phrase> <phrase role="identifier">context</phrase> <phrase role="special">&</phrase> <phrase role="identifier">l</phrase><phrase role="special">,</phrase> <phrase role="identifier">context</phrase> <phrase role="special">&</phrase> <phrase role="identifier">r</phrase><phrase role="special">);</phrase>
+</programlisting>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ As if 'l.swap( r)'.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </section>
+ </section>
+ <section id="context.stack">
+ <title><link linkend="context.stack">Stack allocation</link></title>
+ <para>
+ A <link linkend="context.context.context"><emphasis>context</emphasis></link>
+ requires a stack which will be allocated/deallocated by a <emphasis>StackAllocator</emphasis>.
+ <emphasis role="bold">Boost.Context</emphasis> uses <code><phrase role="identifier">stack_allocator</phrase></code>
+ by default but a customized <code><phrase role="identifier">stack</phrase>
+ <phrase role="identifier">allocator</phrase></code> can be passed to the context
+ constructor instead. If a context is constructed it invokes <emphasis>allocate()</emphasis>
+ function and by its destruction the stack gets released by <emphasis>deallocate()</emphasis>.
+ </para>
+ <anchor id="context.stack._emphasis_stackallocator_concept__emphasis_"/>
+ <bridgehead renderas="sect3">
+ <link linkend="context.stack._emphasis_stackallocator_concept__emphasis_"><emphasis>StackAllocator
+ concept</emphasis></link>
+ </bridgehead>
+ <para>
+ A <emphasis>StackAllocator</emphasis> must satisfy the <emphasis>StackAllocator
+ concept</emphasis> requirements shown in the following table, in which <code><phrase
+ role="identifier">a</phrase></code> is an object of a <emphasis>StackAllocator</emphasis>
+ type, <code><phrase role="identifier">p</phrase></code> is a <code><phrase
+ role="keyword">void</phrase> <phrase role="special">*</phrase></code>, and
+ <code><phrase role="identifier">s</phrase></code> is a <code><phrase role="identifier">std</phrase><phrase
+ role="special">::</phrase><phrase role="identifier">size_t</phrase></code>:
+ </para>
+ <informaltable frame="all">
+ <tgroup cols="3">
+ <thead>
+ <row>
+ <entry>
+ <para>
+ expression
+ </para>
+ </entry>
+ <entry>
+ <para>
+ return type
+ </para>
+ </entry>
+ <entry>
+ <para>
+ notes
+ </para>
+ </entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>
+ <para>
+ <code><phrase role="identifier">a</phrase><phrase role="special">.</phrase><phrase
+ role="identifier">allocate</phrase><phrase role="special">(</phrase>
+ <phrase role="identifier">s</phrase><phrase role="special">)</phrase></code>
+ </para>
+ </entry>
+ <entry>
+ <para>
+ <code><phrase role="keyword">void</phrase> <phrase role="special">*</phrase></code>
+ </para>
+ </entry>
+ <entry>
+ <para>
+ returns a pointer to <code><phrase role="identifier">s</phrase></code>
+ bytes allocated from the stack
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>
+ <para>
+ <code><phrase role="identifier">a</phrase><phrase role="special">.</phrase><phrase
+ role="identifier">deallocate</phrase><phrase role="special">(</phrase>
+ <phrase role="identifier">p</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">s</phrase><phrase role="special">)</phrase></code>
+ </para>
+ </entry>
+ <entry>
+ <para>
+ <code><phrase role="keyword">void</phrase></code>
+ </para>
+ </entry>
+ <entry>
+ <para>
+ deallocates <code><phrase role="identifier">s</phrase></code> bytes
+ of memory beginning at <code><phrase role="identifier">p</phrase></code>,
+ a pointer previously returned by <code><phrase role="identifier">a</phrase><phrase
+ role="special">.</phrase><phrase role="identifier">allocate</phrase><phrase
+ role="special">()</phrase></code>
+ </para>
+ </entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </informaltable>
+ <important>
+ <para>
+ The implementation of <code><phrase role="identifier">allocate</phrase><phrase
+ role="special">()</phrase></code> might include logic to protect against
+ exceeding the context's available stack size rather than leaving it as undefined
+ behaviour.
+ </para>
+ </important>
+ <important>
+ <para>
+ Calling <code><phrase role="identifier">deallocate</phrase><phrase role="special">()</phrase></code>
+ with a pointer not returned by <code><phrase role="identifier">allocate</phrase><phrase
+ role="special">()</phrase></code> results in undefined behaviour.
+ </para>
+ </important>
+ <note>
+ <para>
+ The stack is not required to be aligned; alignment takes place inside <code><phrase
+ role="identifier">boost_fcontext_make</phrase><phrase role="special">()</phrase></code>.
+ </para>
+ </note>
+ <section id="context.stack.stack_allocator">
+ <title><link linkend="context.stack.stack_allocator">Class <code><phrase role="identifier">stack_allocator</phrase></code></link></title>
+ <para>
+ <emphasis role="bold">Boost.Context</emphasis> provides a <emphasis>StackAllocator</emphasis>
+ <code><phrase role="identifier">stack_allocator</phrase></code> which models
+ the <emphasis>StackAllocator concept</emphasis> concept. It appends a <emphasis>guard-page</emphasis>
+ to protect against exceeding the stack. If the guard page is accessed (read
+ or write operation) a segmentation fault/access violation is generated by
+ the operating system.
+ </para>
+ </section>
+ <section id="context.stack.stack_helper">
+ <title><link linkend="context.stack.stack_helper">Helper functions</link></title>
+ <para>
+ <emphasis role="bold">Boost.Context</emphasis> provides easy access to the
+ stack related limits defined by the environment.
+ </para>
+
+<programlisting><phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">default_stacksize</phrase><phrase role="special">();</phrase>
+
+<phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">minimum_stacksize</phrase><phrase role="special">();</phrase>
+
+<phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">maximum_stacksize</phrase><phrase role="special">();</phrase>
+
+<phrase role="keyword">bool</phrase> <phrase role="identifier">is_stack_unbound</phrase><phrase role="special">();</phrase>
+
+<phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">pagesize</phrase><phrase role="special">();</phrase>
+
+<phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">page_count</phrase><phrase role="special">(</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">stacksize</phrase><phrase role="special">);</phrase>
+</programlisting>
+ <anchor id="context.stack.stack_helper._code__phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__default_stacksize__phrase__phrase_role__special______phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.stack.stack_helper._code__phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__default_stacksize__phrase__phrase_role__special______phrase___code_"><code><phrase
+ role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase>
+ <phrase role="identifier">default_stacksize</phrase><phrase role="special">()</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Returns:</term>
+ <listitem>
+ <para>
+ Returns a default stack size, which may be platform specific. The present
+ implementation returns a value of 256 kB.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.stack.stack_helper._code__phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__minimum_stacksize__phrase__phrase_role__special______phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.stack.stack_helper._code__phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__minimum_stacksize__phrase__phrase_role__special______phrase___code_"><code><phrase
+ role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase>
+ <phrase role="identifier">minimum_stacksize</phrase><phrase role="special">()</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Returns:</term>
+ <listitem>
+ <para>
+ Returns the minimum size in bytes of stack defined by the environment.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ Nothing.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.stack.stack_helper._code__phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__maximum_stacksize__phrase__phrase_role__special______phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.stack.stack_helper._code__phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__maximum_stacksize__phrase__phrase_role__special______phrase___code_"><code><phrase
+ role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase>
+ <phrase role="identifier">maximum_stacksize</phrase><phrase role="special">()</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Preconditions:</term>
+ <listitem>
+ <para>
+ <code><phrase role="identifier">is_stack_unbound</phrase><phrase role="special">()</phrase></code>
+ returns <code><phrase role="keyword">false</phrase></code>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Returns:</term>
+ <listitem>
+ <para>
+ Returns the maximum size in bytes of stack defined by the environment.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ Nothing.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.stack.stack_helper._code__phrase_role__keyword__bool__phrase___phrase_role__identifier__is_stack_unbound__phrase__phrase_role__special______phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.stack.stack_helper._code__phrase_role__keyword__bool__phrase___phrase_role__identifier__is_stack_unbound__phrase__phrase_role__special______phrase___code_"><code><phrase
+ role="keyword">bool</phrase> <phrase role="identifier">is_stack_unbound</phrase><phrase
+ role="special">()</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Returns:</term>
+ <listitem>
+ <para>
+ Returns <code><phrase role="keyword">true</phrase></code> if the environment
+ defines no limit for the size of a stack.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ Nothing.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.stack.stack_helper._code__phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__pagesize__phrase__phrase_role__special______phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.stack.stack_helper._code__phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__pagesize__phrase__phrase_role__special______phrase___code_"><code><phrase
+ role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase>
+ <phrase role="identifier">pagesize</phrase><phrase role="special">()</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Returns:</term>
+ <listitem>
+ <para>
+ Returns how many bytes the operating system allocates for one page.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ Nothing.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.stack.stack_helper._code__phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__page_count__phrase__phrase_role__special_____phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__stacksize__phrase__phrase_role__special_____phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.stack.stack_helper._code__phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__page_count__phrase__phrase_role__special_____phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__stacksize__phrase__phrase_role__special_____phrase___code_"><code><phrase
+ role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase>
+ <phrase role="identifier">page_count</phrase><phrase role="special">(</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase
+ role="identifier">size_t</phrase> <phrase role="identifier">stacksize</phrase><phrase
+ role="special">)</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Returns:</term>
+ <listitem>
+ <para>
+ Returns how many pages have to be allocated for a stack of <code><phrase
+ role="identifier">stacksize</phrase></code> bytes.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Throws:</term>
+ <listitem>
+ <para>
+ Nothing.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </section>
+ </section>
+ <section id="context.capi">
+ <title><link linkend="context.capi">Low level API (boost_fcontext_t)</link></title>
+ <para>
+ <emphasis role="bold">Boost.Context</emphasis> uses and provides a low level
+ API which implements the execution control transfer mechanism. The boost_fcontext_t
+ API provides a similar interface like <ulink url="http://www.kernel.org/doc/man-pages/online/pages/man2/getcontext.2.html">ucontext_t</ulink>.
+ boost_fcontext_t and its functions are located in the global namespace and
+ the functions are declared as extern "C".
+ </para>
+
+<programlisting><phrase role="preprocessor">#include</phrase> <phrase role="special"><</phrase><phrase role="identifier">cstdio</phrase><phrase role="special">></phrase>
+<phrase role="preprocessor">#include</phrase> <phrase role="special"><</phrase><phrase role="identifier">cstdlib</phrase><phrase role="special">></phrase>
+<phrase role="preprocessor">#include</phrase> <phrase role="special"><</phrase><phrase role="identifier">cstring</phrase><phrase role="special">></phrase>
+<phrase role="preprocessor">#include</phrase> <phrase role="special"><</phrase><phrase role="identifier">vector</phrase><phrase role="special">></phrase>
+
+<phrase role="preprocessor">#include</phrase> <phrase role="special"><</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">cstdint</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">></phrase>
+<phrase role="preprocessor">#include</phrase> <phrase role="special"><</phrase><phrase role="identifier">boost</phrase><phrase role="special">/</phrase><phrase role="identifier">context</phrase><phrase role="special">/</phrase><phrase role="identifier">fcontext</phrase><phrase role="special">.</phrase><phrase role="identifier">hpp</phrase><phrase role="special">></phrase>
+
+<phrase role="identifier">boost_fcontext_t</phrase> <phrase role="identifier">fcm</phrase><phrase role="special">,</phrase> <phrase role="identifier">fc1</phrase><phrase role="special">,</phrase> <phrase role="identifier">fc2</phrase><phrase role="special">;</phrase>
+
+<phrase role="keyword">void</phrase> <phrase role="identifier">f1</phrase><phrase role="special">(</phrase> <phrase role="identifier">intptr_t</phrase> <phrase role="identifier">p</phrase><phrase role="special">)</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="special">(</phrase><phrase role="keyword">void</phrase><phrase role="special">)</phrase> <phrase role="identifier">p</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">fprintf</phrase><phrase role="special">(</phrase><phrase role="identifier">stderr</phrase><phrase role="special">,</phrase><phrase role="string">"f1() started\n"</phrase><phrase role="special">);</phrase>
+ <phrase role="identifier">fprintf</phrase><phrase role="special">(</phrase><phrase role="identifier">stderr</phrase><phrase role="special">,</phrase><phrase role="string">"f1: call boost_fcontext_jump( & fc1, & fc2, 0)\n"</phrase><phrase role="special">);</phrase>
+ <phrase role="comment">// jump to context fc2
+</phrase> <phrase role="identifier">boost_fcontext_jump</phrase><phrase role="special">(</phrase> <phrase role="special">&</phrase> <phrase role="identifier">fc1</phrase><phrase role="special">,</phrase> <phrase role="special">&</phrase> <phrase role="identifier">fc2</phrase><phrase role="special">,</phrase> <phrase role="number">0</phrase><phrase role="special">);</phrase>
+ <phrase role="comment">// returned from context fc2 (function f2())
+</phrase> <phrase role="comment">// return from function f1()
+</phrase> <phrase role="identifier">fprintf</phrase><phrase role="special">(</phrase><phrase role="identifier">stderr</phrase><phrase role="special">,</phrase><phrase role="string">"f1() returns\n"</phrase><phrase role="special">);</phrase>
+<phrase role="special">}</phrase>
+
+<phrase role="keyword">void</phrase> <phrase role="identifier">f2</phrase><phrase role="special">(</phrase> <phrase role="identifier">intptr_t</phrase> <phrase role="identifier">p</phrase><phrase role="special">)</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="special">(</phrase><phrase role="keyword">void</phrase><phrase role="special">)</phrase> <phrase role="identifier">p</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">fprintf</phrase><phrase role="special">(</phrase><phrase role="identifier">stderr</phrase><phrase role="special">,</phrase><phrase role="string">"f2() started\n"</phrase><phrase role="special">);</phrase>
+ <phrase role="identifier">fprintf</phrase><phrase role="special">(</phrase><phrase role="identifier">stderr</phrase><phrase role="special">,</phrase><phrase role="string">"f2: call boost_fcontext_jump( & fc2, & fc1, 0)\n"</phrase><phrase role="special">);</phrase>
+ <phrase role="comment">// jump to context fc1
+</phrase> <phrase role="identifier">boost_fcontext_jump</phrase><phrase role="special">(</phrase> <phrase role="special">&</phrase> <phrase role="identifier">fc2</phrase><phrase role="special">,</phrase> <phrase role="special">&</phrase> <phrase role="identifier">fc1</phrase><phrase role="special">,</phrase> <phrase role="number">0</phrase><phrase role="special">);</phrase>
+ <phrase role="comment">// never reached
+</phrase> <phrase role="identifier">fprintf</phrase><phrase role="special">(</phrase><phrase role="identifier">stderr</phrase><phrase role="special">,</phrase><phrase role="string">"f2() returns\n"</phrase><phrase role="special">);</phrase>
+<phrase role="special">}</phrase>
+
+<phrase role="keyword">int</phrase> <phrase role="identifier">main</phrase><phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">argc</phrase><phrase role="special">,</phrase> <phrase role="keyword">char</phrase> <phrase role="special">*</phrase> <phrase role="identifier">argv</phrase><phrase role="special">[])</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="comment">// creat two protected stacks
+</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">protected_stack</phrase> <phrase role="identifier">b1</phrase><phrase role="special">(</phrase><phrase role="number">262144</phrase><phrase role="special">);</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">protected_stack</phrase> <phrase role="identifier">b2</phrase><phrase role="special">(</phrase><phrase role="number">262144</phrase><phrase role="special">);</phrase>
+
+ <phrase role="comment">// let context fc1 use stack b1
+</phrase> <phrase role="identifier">fc1</phrase><phrase role="special">.</phrase><phrase role="identifier">fc_stack</phrase><phrase role="special">.</phrase><phrase role="identifier">ss_base</phrase> <phrase role="special">=</phrase> <phrase role="identifier">b1</phrase><phrase role="special">.</phrase><phrase role="identifier">address</phrase><phrase role="special">();</phrase>
+ <phrase role="identifier">fc1</phrase><phrase role="special">.</phrase><phrase role="identifier">fc_stack</phrase><phrase role="special">.</phrase><phrase role="identifier">ss_limit</phrase> <phrase role="special">=</phrase>
+ <phrase role="keyword">static_cast</phrase><phrase role="special"><</phrase> <phrase role="keyword">char</phrase> <phrase role="special">*</phrase> <phrase role="special">>(</phrase> <phrase role="identifier">fc1</phrase><phrase role="special">.</phrase><phrase role="identifier">fc_stack</phrase><phrase role="special">.</phrase><phrase role="identifier">ss_base</phrase><phrase role="special">)</phrase> <phrase role="special">-</phrase> <phrase role="identifier">b1</phrase><phrase role="special">.</phrase><phrase role="identifier">size</phrase><phrase role="special">();</phrase>
+ <phrase role="comment">// link context fcm;
+</phrase> <phrase role="comment">// fcm will be invoked after fc1 terminated
+</phrase> <phrase role="identifier">fc1</phrase><phrase role="special">.</phrase><phrase role="identifier">fc_link</phrase> <phrase role="special">=</phrase> <phrase role="special">&</phrase> <phrase role="identifier">fcm</phrase><phrase role="special">;</phrase>
+ <phrase role="comment">// context fc1 used f1() as context function
+</phrase> <phrase role="identifier">boost_fcontext_make</phrase><phrase role="special">(</phrase> <phrase role="special">&</phrase> <phrase role="identifier">fc1</phrase><phrase role="special">,</phrase> <phrase role="identifier">f1</phrase><phrase role="special">,</phrase> <phrase role="number">0</phrase><phrase role="special">);</phrase>
+
+ <phrase role="comment">// let context fc2 use stack b2
+</phrase> <phrase role="identifier">fc2</phrase><phrase role="special">.</phrase><phrase role="identifier">fc_stack</phrase><phrase role="special">.</phrase><phrase role="identifier">ss_base</phrase> <phrase role="special">=</phrase> <phrase role="identifier">b2</phrase><phrase role="special">.</phrase><phrase role="identifier">address</phrase><phrase role="special">();</phrase>
+ <phrase role="identifier">fc2</phrase><phrase role="special">.</phrase><phrase role="identifier">fc_stack</phrase><phrase role="special">.</phrase><phrase role="identifier">ss_limit</phrase> <phrase role="special">=</phrase>
+ <phrase role="keyword">static_cast</phrase><phrase role="special"><</phrase> <phrase role="keyword">char</phrase> <phrase role="special">*</phrase> <phrase role="special">>(</phrase> <phrase role="identifier">fc2</phrase><phrase role="special">.</phrase><phrase role="identifier">fc_stack</phrase><phrase role="special">.</phrase><phrase role="identifier">ss_base</phrase><phrase role="special">)</phrase> <phrase role="special">-</phrase> <phrase role="identifier">b2</phrase><phrase role="special">.</phrase><phrase role="identifier">size</phrase><phrase role="special">();</phrase>
+ <phrase role="comment">// context fc2 used f2() as context function
+</phrase> <phrase role="identifier">boost_fcontext_make</phrase><phrase role="special">(</phrase> <phrase role="special">&</phrase> <phrase role="identifier">fc2</phrase><phrase role="special">,</phrase> <phrase role="identifier">f2</phrase><phrase role="special">,</phrase> <phrase role="number">0</phrase><phrase role="special">);</phrase>
+
+ <phrase role="comment">// start context f1; entering f1()
+</phrase> <phrase role="identifier">fprintf</phrase><phrase role="special">(</phrase><phrase role="identifier">stderr</phrase><phrase role="special">,</phrase><phrase role="string">"main: call boost_fcontext_start( & fcm, & fc1)\n"</phrase><phrase role="special">);</phrase>
+ <phrase role="identifier">boost_fcontext_start</phrase><phrase role="special">(</phrase> <phrase role="special">&</phrase> <phrase role="identifier">fcm</phrase><phrase role="special">,</phrase> <phrase role="special">&</phrase> <phrase role="identifier">fc1</phrase><phrase role="special">);</phrase>
+
+ <phrase role="identifier">fprintf</phrase><phrase role="special">(</phrase> <phrase role="identifier">stderr</phrase><phrase role="special">,</phrase> <phrase role="string">"main() returns\n"</phrase><phrase role="special">);</phrase>
+ <phrase role="keyword">return</phrase> <phrase role="identifier">EXIT_SUCCESS</phrase><phrase role="special">;</phrase>
+<phrase role="special">}</phrase>
+
+<phrase role="identifier">output</phrase><phrase role="special">:</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">:</phrase> <phrase role="identifier">call</phrase> <phrase role="identifier">boost_fcontext_start</phrase><phrase role="special">(</phrase> <phrase role="special">&</phrase> <phrase role="identifier">fcm</phrase><phrase role="special">,</phrase> <phrase role="special">&</phrase> <phrase role="identifier">fc1</phrase><phrase role="special">)</phrase>
+ <phrase role="identifier">f1</phrase><phrase role="special">()</phrase> <phrase role="identifier">started</phrase>
+ <phrase role="identifier">f1</phrase><phrase role="special">:</phrase> <phrase role="identifier">call</phrase> <phrase role="identifier">boost_fcontext_jump</phrase><phrase role="special">(</phrase> <phrase role="special">&</phrase> <phrase role="identifier">fc1</phrase><phrase role="special">,</phrase> <phrase role="special">&</phrase> <phrase role="identifier">fc2</phrase><phrase role="special">,</phrase> <phrase role="number">0</phrase><phrase role="special">)</phrase>
+ <phrase role="identifier">f2</phrase><phrase role="special">()</phrase> <phrase role="identifier">started</phrase>
+ <phrase role="identifier">f2</phrase><phrase role="special">:</phrase> <phrase role="identifier">call</phrase> <phrase role="identifier">boost_fcontext_jump</phrase><phrase role="special">(</phrase> <phrase role="special">&</phrase> <phrase role="identifier">fc2</phrase><phrase role="special">,</phrase> <phrase role="special">&</phrase> <phrase role="identifier">fc1</phrase><phrase role="special">,</phrase> <phrase role="number">0</phrase><phrase role="special">)</phrase>
+ <phrase role="identifier">f1</phrase><phrase role="special">()</phrase> <phrase role="identifier">returns</phrase>
+ <phrase role="identifier">main</phrase><phrase role="special">()</phrase> <phrase role="identifier">returns</phrase>
+</programlisting>
+ <para>
+ Function <code><phrase role="identifier">boost_fcontext_start</phrase><phrase
+ role="special">()</phrase></code> enters the <emphasis>context-function</emphasis>
+ <code><phrase role="identifier">f1</phrase><phrase role="special">()</phrase></code>
+ by starting context fc1 (context fcm saves the registers of <code><phrase role="identifier">main</phrase><phrase
+ role="special">()</phrase></code>). For jumping between context's fc1 and fc2
+ <code><phrase role="identifier">boost_fcontext_jump</phrase><phrase role="special">()</phrase></code>
+ is called. Because context fcm is chained to fc1, <code><phrase role="identifier">main</phrase><phrase
+ role="special">()</phrase></code> is entered (returning from <code><phrase
+ role="identifier">boost_fcontext_start</phrase><phrase role="special">()</phrase></code>)
+ after context fc1 becomes complete (return from <code><phrase role="identifier">f1</phrase><phrase
+ role="special">()</phrase></code>).
+ </para>
+ <important>
+ <para>
+ The low level API is the part to port to new platforms.
+ </para>
+ </important>
+ <section id="context.capi.boost_fcontext">
+ <title><link linkend="context.capi.boost_fcontext">Struct <code><phrase role="identifier">boost_fcontext_t</phrase></code>
+ and related functions</link></title>
+<programlisting><phrase role="keyword">typedef</phrase> <phrase role="keyword">struct</phrase> <phrase role="identifier">boost_fcontext_stack</phrase> <phrase role="identifier">boost_fcontext_stack_t</phrase><phrase role="special">;</phrase>
+<phrase role="keyword">struct</phrase> <phrase role="identifier">boost_fcontext_stack</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="keyword">void</phrase> <phrase role="special">*</phrase> <phrase role="identifier">ss_base</phrase><phrase role="special">;</phrase>
+ <phrase role="keyword">void</phrase> <phrase role="special">*</phrase> <phrase role="identifier">ss_limit</phrase><phrase role="special">;</phrase>
+<phrase role="special">};</phrase>
+
+<phrase role="keyword">typedef</phrase> <phrase role="keyword">struct</phrase> <phrase role="identifier">boost_fcontext</phrase> <phrase role="identifier">boost_fcontext_t</phrase><phrase role="special">;</phrase>
+<phrase role="keyword">struct</phrase> <phrase role="identifier">boost_fcontext</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="special"><</phrase> <phrase role="identifier">platform</phrase> <phrase role="identifier">specific</phrase> <phrase role="special">></phrase>
+
+ <phrase role="identifier">boost_fcontext_stack_t</phrase> <phrase role="identifier">fc_stack</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">boost_fcontext_t</phrase> <phrase role="special">*</phrase> <phrase role="identifier">fc_link</phrase><phrase role="special">;</phrase>
+<phrase role="special">};</phrase>
+
+<phrase role="identifier">intptr_t</phrase> <phrase role="identifier">boost_fcontext_start</phrase><phrase role="special">(</phrase> <phrase role="identifier">boost_fcontext_t</phrase> <phrase role="special">*</phrase> <phrase role="identifier">ofc</phrase><phrase role="special">,</phrase> <phrase role="identifier">boost_fcontext_t</phrase> <phrase role="keyword">const</phrase><phrase role="special">*</phrase> <phrase role="identifier">nfc</phrase><phrase role="special">);</phrase>
+<phrase role="identifier">intptr_t</phrase> <phrase role="identifier">boost_fcontext_jump</phrase><phrase role="special">(</phrase> <phrase role="identifier">boost_fcontext_t</phrase> <phrase role="special">*</phrase> <phrase role="identifier">ofc</phrase><phrase role="special">,</phrase> <phrase role="identifier">boost_fcontext_t</phrase> <phrase role="keyword">const</phrase><phrase role="special">*</phrase> <phrase role="identifier">nfc</phrase><phrase role="special">,</phrase> <phrase role="identifier">intptr_t</phrase> <phrase role="identifier">vp</phrase><phrase role="special">);</phrase>
+<phrase role="keyword">void</phrase> <phrase role="identifier">boost_fcontext_make</phrase><phrase role="special">(</phrase> <phrase role="identifier">boost_fcontext_t</phrase> <phrase role="special">*</phrase> <phrase role="identifier">fc</phrase><phrase role="special">,</phrase> <phrase role="keyword">void</phrase><phrase role="special">(*</phrase> <phrase role="identifier">fn</phrase><phrase role="special">)(</phrase><phrase role="keyword">void</phrase><phrase role="special">*),</phrase> <phrase role="identifier">intptr_t</phrase> <phrase role="identifier">p</phrase><phrase role="special">);</phrase>
+</programlisting>
+ <anchor id="context.capi.boost_fcontext._code__phrase_role__identifier__ss_base__phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.capi.boost_fcontext._code__phrase_role__identifier__ss_base__phrase___code_"><code><phrase
+ role="identifier">ss_base</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Member:</term>
+ <listitem>
+ <para>
+ Pointer to the top of the stack.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.capi.boost_fcontext._code__phrase_role__identifier__ss_limit__phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.capi.boost_fcontext._code__phrase_role__identifier__ss_limit__phrase___code_"><code><phrase
+ role="identifier">ss_limit</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Member:</term>
+ <listitem>
+ <para>
+ Pointer to the bottom of the stack.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.capi.boost_fcontext._code__phrase_role__identifier__fc_stack__phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.capi.boost_fcontext._code__phrase_role__identifier__fc_stack__phrase___code_"><code><phrase
+ role="identifier">fc_stack</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Member:</term>
+ <listitem>
+ <para>
+ Tracks the memory for the context's stack.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.capi.boost_fcontext._code__phrase_role__identifier__fc_link__phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.capi.boost_fcontext._code__phrase_role__identifier__fc_link__phrase___code_"><code><phrase
+ role="identifier">fc_link</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Member:</term>
+ <listitem>
+ <para>
+ The address of the next context link in a chain, if any.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.capi.boost_fcontext._code__phrase_role__identifier__intptr_t__phrase___phrase_role__identifier__boost_fcontext_start__phrase__phrase_role__special_____phrase___phrase_role__identifier__boost_fcontext_t__phrase___phrase_role__special_____phrase___phrase_role__identifier__ofc__phrase__phrase_role__special_____phrase_____phrase_role__identifier__boost_fcontext_t__phrase___phrase_role__special_____phrase___phrase_role__identifier__nfc__phrase__phrase_role__special_____phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.capi.boost_fcontext._code__phrase_role__identifier__intptr_t__phrase___phrase_role__identifier__boost_fcontext_start__phrase__phrase_role__special_____phrase___phrase_role__identifier__boost_fcontext_t__phrase___phrase_role__special_____phrase___phrase_role__identifier__ofc__phrase__phrase_role__special_____phrase_____phrase_role__identifier__boost_fcontext_t__phrase___phrase_role__special_____phrase___phrase_role__identifier__nfc__phrase__phrase_role__special_____phrase___code_"><code><phrase
+ role="identifier">intptr_t</phrase> <phrase role="identifier">boost_fcontext_start</phrase><phrase
+ role="special">(</phrase> <phrase role="identifier">boost_fcontext_t</phrase>
+ <phrase role="special">*</phrase> <phrase role="identifier">ofc</phrase><phrase
+ role="special">,</phrase> <phrase role="identifier">boost_fcontext_t</phrase>
+ <phrase role="special">*</phrase> <phrase role="identifier">nfc</phrase><phrase
+ role="special">)</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ Stores the current context data (stack pointer, instruction pointer,
+ and CPU registers) to <code><phrase role="special">*</phrase><phrase
+ role="identifier">ofc</phrase></code> and restores the context data
+ from <code><phrase role="special">*</phrase><phrase role="identifier">nfc</phrase></code>,
+ which implies jumping to <code><phrase role="special">*</phrase><phrase
+ role="identifier">nfc</phrase></code>'s execution context. This function
+ must be called when first entering <code><phrase role="special">*</phrase><phrase
+ role="identifier">nfc</phrase></code>'s execution context.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Returns:</term>
+ <listitem>
+ <para>
+ The result of calling <code><phrase role="identifier">boost_fcontext_jump</phrase><phrase
+ role="special">()</phrase></code>.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.capi.boost_fcontext._code__phrase_role__identifier__intptr_t__phrase___phrase_role__identifier__boost_fcontext_jump__phrase__phrase_role__special_____phrase___phrase_role__identifier__boost_fcontext_t__phrase___phrase_role__special_____phrase___phrase_role__identifier__ofc__phrase__phrase_role__special_____phrase___phrase_role__identifier__boost_fcontext_t__phrase___phrase_role__special_____phrase___phrase_role__identifier__nfc__phrase__phrase_role__special_____phrase___phrase_role__identifier__intptr_t__phrase___phrase_role__identifier__p__phrase__phrase_role__special_____phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.capi.boost_fcontext._code__phrase_role__identifier__intptr_t__phrase___phrase_role__identifier__boost_fcontext_jump__phrase__phrase_role__special_____phrase___phrase_role__identifier__boost_fcontext_t__phrase___phrase_role__special_____phrase___phrase_role__identifier__ofc__phrase__phrase_role__special_____phrase___phrase_role__identifier__boost_fcontext_t__phrase___phrase_role__special_____phrase___phrase_role__identifier__nfc__phrase__phrase_role__special_____phrase___phrase_role__identifier__intptr_t__phrase___phrase_role__identifier__p__phrase__phrase_role__special_____phrase___code_"><code><phrase
+ role="identifier">intptr_t</phrase> <phrase role="identifier">boost_fcontext_jump</phrase><phrase
+ role="special">(</phrase> <phrase role="identifier">boost_fcontext_t</phrase>
+ <phrase role="special">*</phrase> <phrase role="identifier">ofc</phrase><phrase
+ role="special">,</phrase> <phrase role="identifier">boost_fcontext_t</phrase>
+ <phrase role="special">*</phrase> <phrase role="identifier">nfc</phrase><phrase
+ role="special">,</phrase> <phrase role="identifier">intptr_t</phrase> <phrase
+ role="identifier">p</phrase><phrase role="special">)</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ Stores the current context data (stack pointer, instruction pointer,
+ and CPU registers) to <code><phrase role="special">*</phrase><phrase
+ role="identifier">ofc</phrase></code> and restores the context data
+ from <code><phrase role="special">*</phrase><phrase role="identifier">nfc</phrase></code>,
+ which implies jumping to <code><phrase role="special">*</phrase><phrase
+ role="identifier">nfc</phrase></code>'s execution context. The intptr_t
+ argument, <code><phrase role="identifier">p</phrase></code>, is passed
+ to the current context to be returned by the most recent call to <code><phrase
+ role="identifier">boost_fcontext_start</phrase><phrase role="special">()</phrase></code>
+ or <code><phrase role="identifier">boost_fcontext_jump</phrase><phrase
+ role="special">()</phrase></code> in the same thread.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Returns:</term>
+ <listitem>
+ <para>
+ The third pointer argument passed to the most recent call to <code><phrase
+ role="identifier">boost_fcontext_jump</phrase><phrase role="special">()</phrase></code>,
+ if any.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <anchor id="context.capi.boost_fcontext._code__phrase_role__keyword__void__phrase___phrase_role__identifier__boost_fcontext_make__phrase__phrase_role__special_____phrase___phrase_role__identifier__boost_fcontext_t__phrase___phrase_role__special_____phrase___phrase_role__identifier__fc__phrase__phrase_role__special_____phrase___phrase_role__keyword__void__phrase__phrase_role__special______phrase__phrase_role__identifier__fn__phrase__phrase_role__special______phrase__phrase_role__identifier__intptr_t__phrase__phrase_role__special______phrase___phrase_role__identifier__intptr_t__phrase___phrase_role__identifier__p__phrase__phrase_role__special_____phrase___code_"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.capi.boost_fcontext._code__phrase_role__keyword__void__phrase___phrase_role__identifier__boost_fcontext_make__phrase__phrase_role__special_____phrase___phrase_role__identifier__boost_fcontext_t__phrase___phrase_role__special_____phrase___phrase_role__identifier__fc__phrase__phrase_role__special_____phrase___phrase_role__keyword__void__phrase__phrase_role__special______phrase__phrase_role__identifier__fn__phrase__phrase_role__special______phrase__phrase_role__identifier__intptr_t__phrase__phrase_role__special______phrase___phrase_role__identifier__intptr_t__phrase___phrase_role__identifier__p__phrase__phrase_role__special_____phrase___code_"><code><phrase
+ role="keyword">void</phrase> <phrase role="identifier">boost_fcontext_make</phrase><phrase
+ role="special">(</phrase> <phrase role="identifier">boost_fcontext_t</phrase>
+ <phrase role="special">*</phrase> <phrase role="identifier">fc</phrase><phrase
+ role="special">,</phrase> <phrase role="keyword">void</phrase><phrase role="special">(*</phrase><phrase
+ role="identifier">fn</phrase><phrase role="special">)(</phrase><phrase role="identifier">intptr_t</phrase><phrase
+ role="special">),</phrase> <phrase role="identifier">intptr_t</phrase> <phrase
+ role="identifier">p</phrase><phrase role="special">)</phrase></code></link>
+ </bridgehead>
+ <variablelist>
+ <title></title>
+ <varlistentry>
+ <term>Precondition:</term>
+ <listitem>
+ <para>
+ A stack is applied to <code><phrase role="special">*</phrase><phrase
+ role="identifier">fc</phrase></code> before <code><phrase role="identifier">boost_fcontext_make</phrase><phrase
+ role="special">()</phrase></code> is called. If a successor context
+ should be executed after <code><phrase role="special">*</phrase><phrase
+ role="identifier">fc</phrase></code> finishes the address of the successor
+ context must be stored ir <code><phrase role="identifier">fc</phrase><phrase
+ role="special">-></phrase><phrase role="identifier">fc_link</phrase></code>.
+ The application exits otherwise.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effects:</term>
+ <listitem>
+ <para>
+ Modifies <code><phrase role="special">*</phrase><phrase role="identifier">fc</phrase></code>
+ in order to execute <code><phrase role="identifier">fn</phrase></code>
+ with argument <code><phrase role="identifier">p</phrase></code> when
+ the context is activated next.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </section>
+ </section>
+ <section id="context.examples">
+ <title><link linkend="context.examples">Examples</link></title>
+ <section id="context.examples.enumerator">
+ <title><link linkend="context.examples.enumerator">Enumerator</link></title>
+ <para>
+ Class <code><phrase role="identifier">power</phrase></code> computes the
+ power of <code><phrase role="identifier">number</phrase></code> for the exponents
+ in the range from <code><phrase role="number">1</phrase></code> to <code><phrase
+ role="identifier">number</phrase></code> (constructor arguments).
+ </para>
+
+<programlisting><phrase role="keyword">class</phrase> <phrase role="identifier">power</phrase>
+<phrase role="special">{</phrase>
+<phrase role="keyword">public</phrase><phrase role="special">:</phrase>
+ <phrase role="identifier">power</phrase><phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">number</phrase><phrase role="special">,</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">exponent</phrase><phrase role="special">);</phrase>
+
+ <phrase role="keyword">bool</phrase> <phrase role="identifier">get</phrase><phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="special">&</phrase> <phrase role="identifier">data</phrase><phrase role="special">);</phrase>
+<phrase role="special">};</phrase>
+</programlisting>
+ <para>
+ Each call to <code><phrase role="identifier">power</phrase><phrase role="special">::</phrase><phrase
+ role="identifier">get</phrase><phrase role="special">()</phrase></code> returns
+ a boolean indicating a vaild result. The reference argument <code><phrase
+ role="identifier">data</phrase></code> contains the computed result.
+ </para>
+
+<programlisting><phrase role="keyword">int</phrase> <phrase role="identifier">main</phrase><phrase role="special">()</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="identifier">power</phrase> <phrase role="identifier">pw</phrase><phrase role="special">(</phrase> <phrase role="number">2</phrase><phrase role="special">,</phrase> <phrase role="number">8</phrase><phrase role="special">);</phrase>
+ <phrase role="keyword">int</phrase> <phrase role="identifier">i</phrase><phrase role="special">;</phrase>
+ <phrase role="comment">// pw.get() returns the computed result
+</phrase> <phrase role="comment">// for each value from 1 to 8
+</phrase> <phrase role="comment">// return value of pw.get() indicates that
+</phrase> <phrase role="comment">// a valid result
+</phrase> <phrase role="keyword">while</phrase> <phrase role="special">(</phrase> <phrase role="identifier">pw</phrase><phrase role="special">.</phrase><phrase role="identifier">get</phrase><phrase role="special">(</phrase> <phrase role="identifier">i</phrase><phrase role="special">)</phrase> <phrase role="special">)</phrase> <phrase role="special">{</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">i</phrase> <phrase role="special"><<</phrase> <phrase role="string">" "</phrase><phrase role="special">;</phrase>
+ <phrase role="special">}</phrase>
+ <phrase role="special">}</phrase>
+
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"\nDone"</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+
+ <phrase role="keyword">return</phrase> <phrase role="identifier">EXIT_SUCCESS</phrase><phrase role="special">;</phrase>
+<phrase role="special">}</phrase>
+
+<phrase role="identifier">output</phrase><phrase role="special">:</phrase>
+ <phrase role="number">2</phrase> <phrase role="number">4</phrase> <phrase role="number">8</phrase> <phrase role="number">16</phrase> <phrase role="number">32</phrase> <phrase role="number">64</phrase> <phrase role="number">128</phrase> <phrase role="number">256</phrase>
+ <phrase role="identifier">Done</phrase>
+</programlisting>
+ <para>
+ In <code><phrase role="identifier">main</phrase><phrase role="special">()</phrase></code>
+ an instance of <code><phrase role="identifier">power</phrase></code> is constructed,
+ computing the power of 2 for exponents in the range from 1 to 8 by each call
+ to <code><phrase role="identifier">power</phrase><phrase role="special">::</phrase><phrase
+ role="identifier">get</phrase><phrase role="special">()</phrase></code>.
+ </para>
+ <para>
+ It is intended to compute the numbers in a loop and transfer each result
+ to the caller without disrupting the loop.
+ </para>
+ <para>
+ <emphasis role="bold">Boost.Context</emphasis> can be used to implement an
+ equivalent to C#'s <code><phrase role="identifier">yield</phrase></code>
+ facility (C# provides the keywords <code><phrase role="identifier">yield</phrase>
+ <phrase role="keyword">return</phrase></code> and <code><phrase role="identifier">yield</phrase>
+ <phrase role="keyword">break</phrase></code>). For this purpose helper-template
+ <code><phrase role="identifier">enumerator</phrase></code> is defined containing
+ the private member <code><phrase role="identifier">ctx_</phrase></code> executing
+ <code><phrase role="identifier">enumerate</phrase><phrase role="special">()</phrase></code>
+ as <emphasis>context-function</emphasis>.
+ </para>
+
+<programlisting><phrase role="keyword">template</phrase><phrase role="special"><</phrase> <phrase role="keyword">typename</phrase> <phrase role="identifier">T</phrase> <phrase role="special">></phrase>
+<phrase role="keyword">class</phrase> <phrase role="identifier">enumerator</phrase> <phrase role="special">{</phrase>
+<phrase role="keyword">private</phrase><phrase role="special">:</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">context</phrase> <phrase role="identifier">ctx_</phrase><phrase role="special">;</phrase>
+ <phrase role="keyword">bool</phrase> <phrase role="identifier">complete_</phrase><phrase role="special">;</phrase>
+ <phrase role="keyword">bool</phrase> <phrase role="identifier">do_unwind_</phrase><phrase role="special">;</phrase>
+ <phrase role="keyword">bool</phrase> <phrase role="identifier">started_</phrase><phrase role="special">;</phrase>
+
+ <phrase role="keyword">static</phrase> <phrase role="keyword">void</phrase> <phrase role="identifier">run</phrase><phrase role="special">(</phrase> <phrase role="identifier">enumerator</phrase> <phrase role="special">*</phrase> <phrase role="identifier">self</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{</phrase> <phrase role="identifier">self</phrase><phrase role="special">-></phrase><phrase role="identifier">enumerate</phrase><phrase role="special">();</phrase> <phrase role="special">}</phrase>
+
+<phrase role="keyword">protected</phrase><phrase role="special">:</phrase>
+ <phrase role="keyword">virtual</phrase> <phrase role="keyword">void</phrase> <phrase role="identifier">enumerate</phrase><phrase role="special">()</phrase> <phrase role="special">=</phrase> <phrase role="number">0</phrase><phrase role="special">;</phrase>
+
+ <phrase role="keyword">void</phrase> <phrase role="identifier">yield_return</phrase><phrase role="special">(</phrase> <phrase role="identifier">T</phrase> <phrase role="keyword">const</phrase><phrase role="special">&</phrase> <phrase role="identifier">v</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="identifier">intptr_t</phrase> <phrase role="identifier">vp</phrase> <phrase role="special">=</phrase> <phrase role="keyword">reinterpret_cast</phrase><phrase role="special"><</phrase> <phrase role="identifier">intptr_t</phrase> <phrase role="special">>(</phrase> <phrase role="special">&</phrase> <phrase role="identifier">v</phrase><phrase role="special">);</phrase>
+ <phrase role="identifier">ctx_</phrase><phrase role="special">.</phrase><phrase role="identifier">suspend</phrase><phrase role="special">(</phrase> <phrase role="identifier">vp</phrase><phrase role="special">);</phrase>
+ <phrase role="special">}</phrase>
+
+ <phrase role="keyword">void</phrase> <phrase role="identifier">yield_break</phrase><phrase role="special">()</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="identifier">complete_</phrase> <phrase role="special">=</phrase> <phrase role="keyword">true</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">ctx_</phrase><phrase role="special">.</phrase><phrase role="identifier">suspend</phrase><phrase role="special">();</phrase>
+ <phrase role="special">}</phrase>
+
+<phrase role="keyword">public</phrase><phrase role="special">:</phrase>
+ <phrase role="identifier">enumerator</phrase><phrase role="special">(</phrase> <phrase role="keyword">bool</phrase> <phrase role="identifier">do_unwind</phrase> <phrase role="special">=</phrase> <phrase role="keyword">true</phrase><phrase role="special">):</phrase>
+ <phrase role="identifier">ctx_</phrase><phrase role="special">(</phrase>
+ <phrase role="special">&</phrase> <phrase role="identifier">enumerator</phrase><phrase role="special">::</phrase><phrase role="identifier">run</phrase><phrase role="special">,</phrase> <phrase role="keyword">this</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">default_stacksize</phrase><phrase role="special">(),</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">no_stack_unwind</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">return_to_caller</phrase><phrase role="special">),</phrase>
+ <phrase role="identifier">complete_</phrase><phrase role="special">(</phrase> <phrase role="keyword">false</phrase><phrase role="special">),</phrase>
+ <phrase role="identifier">do_unwind_</phrase><phrase role="special">(</phrase> <phrase role="identifier">do_unwind</phrase><phrase role="special">),</phrase>
+ <phrase role="identifier">started_</phrase><phrase role="special">(</phrase> <phrase role="keyword">false</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{}</phrase>
+
+ <phrase role="special">~</phrase><phrase role="identifier">enumerator</phrase><phrase role="special">()</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="keyword">if</phrase> <phrase role="special">(</phrase> <phrase role="identifier">do_unwind_</phrase> <phrase role="special">&&</phrase> <phrase role="special">!</phrase> <phrase role="identifier">ctx_</phrase><phrase role="special">.</phrase><phrase role="identifier">is_complete</phrase><phrase role="special">()</phrase> <phrase role="special">)</phrase>
+ <phrase role="identifier">ctx_</phrase><phrase role="special">.</phrase><phrase role="identifier">unwind_stack</phrase><phrase role="special">();</phrase>
+ <phrase role="special">}</phrase>
+
+ <phrase role="keyword">bool</phrase> <phrase role="identifier">get</phrase><phrase role="special">(</phrase> <phrase role="identifier">T</phrase> <phrase role="special">&</phrase> <phrase role="identifier">result</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="identifier">intptr_t</phrase> <phrase role="identifier">vp</phrase> <phrase role="special">=</phrase> <phrase role="number">0</phrase><phrase role="special">;</phrase>
+ <phrase role="keyword">if</phrase> <phrase role="special">(</phrase> <phrase role="special">!</phrase> <phrase role="identifier">started_</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="identifier">started_</phrase> <phrase role="special">=</phrase> <phrase role="keyword">true</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">vp</phrase> <phrase role="special">=</phrase> <phrase role="identifier">ctx_</phrase><phrase role="special">.</phrase><phrase role="identifier">start</phrase><phrase role="special">();</phrase>
+ <phrase role="special">}</phrase>
+ <phrase role="keyword">else</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="identifier">vp</phrase> <phrase role="special">=</phrase> <phrase role="identifier">ctx_</phrase><phrase role="special">.</phrase><phrase role="identifier">resume</phrase><phrase role="special">();</phrase>
+ <phrase role="special">}</phrase>
+ <phrase role="keyword">if</phrase> <phrase role="special">(</phrase> <phrase role="identifier">vp</phrase><phrase role="special">)</phrase> <phrase role="identifier">result</phrase> <phrase role="special">=</phrase> <phrase role="special">*</phrase> <phrase role="keyword">reinterpret_cast</phrase><phrase role="special"><</phrase> <phrase role="identifier">T</phrase> <phrase role="special">*</phrase> <phrase role="special">>(</phrase> <phrase role="identifier">vp</phrase><phrase role="special">);</phrase>
+ <phrase role="keyword">return</phrase> <phrase role="special">!</phrase> <phrase role="special">(</phrase> <phrase role="identifier">complete_</phrase> <phrase role="special">||</phrase> <phrase role="identifier">ctx_</phrase><phrase role="special">.</phrase><phrase role="identifier">is_complete</phrase><phrase role="special">()</phrase> <phrase role="special">);</phrase>
+ <phrase role="special">}</phrase>
+<phrase role="special">};</phrase>
+</programlisting>
+ <para>
+ Member-function <code><phrase role="identifier">get</phrase><phrase role="special">()</phrase></code>
+ starts / resumes <code><phrase role="identifier">context</phrase> </code>ctx_<code>
+ <phrase role="identifier">by</phrase> <phrase role="identifier">calling</phrase>
+ <emphasis>context::start()</emphasis> <phrase role="special">/</phrase>
+ <emphasis>context::resume()</emphasis> <phrase role="identifier">so</phrase>
+ <phrase role="identifier">that</phrase> </code>enumerate()` is (re-)entered.
+ Functions <emphasis>context::start()</emphasis> / <emphasis>context::resume()</emphasis>
+ return the computed values.
+ </para>
+ <para>
+ <code><phrase role="identifier">yield_return</phrase><phrase role="special">()</phrase></code>
+ (equivalent to C# <code><phrase role="identifier">yield</phrase> <phrase
+ role="keyword">return</phrase></code>) jumps to <code><phrase role="identifier">get</phrase><phrase
+ role="special">()</phrase></code> transfering the execution control and computed
+ value back. With <code><phrase role="identifier">yield_break</phrase><phrase
+ role="special">()</phrase></code> (equivalent to C# <code><phrase role="identifier">yield</phrase>
+ <phrase role="keyword">break</phrase></code>) the control is unconditionally
+ returned to <code><phrase role="identifier">get</phrase><phrase role="special">()</phrase></code>
+ to signal the end of iteration.
+ </para>
+ <para>
+ Class <code><phrase role="identifier">power</phrase></code> derives from
+ <code><phrase role="identifier">enumerate</phrase><phrase role="special"><</phrase>
+ <phrase role="keyword">int</phrase> <phrase role="special">></phrase></code>
+ and its implementation of <code><phrase role="identifier">enumerate</phrase><phrase
+ role="special">()</phrase></code> computes the power in a local loop. Each
+ computed result is transfered to <code><phrase role="identifier">get</phrase><phrase
+ role="special">()</phrase></code> by calling <code><phrase role="identifier">yield_return</phrase><phrase
+ role="special">()</phrase></code>.
+ </para>
+
+<programlisting><phrase role="keyword">class</phrase> <phrase role="identifier">power</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <phrase role="identifier">enumerator</phrase><phrase role="special"><</phrase> <phrase role="keyword">int</phrase> <phrase role="special">></phrase>
+<phrase role="special">{</phrase>
+<phrase role="keyword">private</phrase><phrase role="special">:</phrase>
+ <phrase role="keyword">void</phrase> <phrase role="identifier">enumerate</phrase><phrase role="special">()</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="keyword">int</phrase> <phrase role="identifier">counter</phrase> <phrase role="special">=</phrase> <phrase role="number">0</phrase><phrase role="special">;</phrase>
+ <phrase role="keyword">int</phrase> <phrase role="identifier">result</phrase> <phrase role="special">=</phrase> <phrase role="number">1</phrase><phrase role="special">;</phrase>
+ <phrase role="comment">// local scoped while loop
+</phrase> <phrase role="keyword">while</phrase> <phrase role="special">(</phrase> <phrase role="identifier">counter</phrase><phrase role="special">++</phrase> <phrase role="special"><</phrase> <phrase role="identifier">exponent_</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="comment">// compute the value
+</phrase> <phrase role="identifier">result</phrase> <phrase role="special">=</phrase> <phrase role="identifier">result</phrase> <phrase role="special">*</phrase> <phrase role="identifier">number_</phrase><phrase role="special">;</phrase>
+
+ <phrase role="comment">// return the value by jumping to calling context
+</phrase> <phrase role="comment">// == jump to while-loop in main()
+</phrase> <phrase role="identifier">yield_return</phrase><phrase role="special">(</phrase> <phrase role="identifier">result</phrase><phrase role="special">);</phrase>
+ <phrase role="special">}</phrase>
+ <phrase role="special">}</phrase>
+
+ <phrase role="keyword">int</phrase> <phrase role="identifier">number_</phrase><phrase role="special">;</phrase>
+ <phrase role="keyword">int</phrase> <phrase role="identifier">exponent_</phrase><phrase role="special">;</phrase>
+
+<phrase role="keyword">public</phrase><phrase role="special">:</phrase>
+ <phrase role="identifier">power</phrase><phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">number</phrase><phrase role="special">,</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">exponent</phrase><phrase role="special">)</phrase> <phrase role="special">:</phrase>
+ <phrase role="identifier">number_</phrase><phrase role="special">(</phrase> <phrase role="identifier">number</phrase><phrase role="special">),</phrase> <phrase role="identifier">exponent_</phrase><phrase role="special">(</phrase> <phrase role="identifier">exponent</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{}</phrase>
+<phrase role="special">};</phrase>
+</programlisting>
+ </section>
+ <section id="context.examples.continuation">
+ <title><link linkend="context.examples.continuation">Continuation</link></title>
+ <para>
+ Adapted from <ulink url="https://code.google.com/p/jyield/wiki/Samples">the
+ Java continuation</ulink> documentation example.
+ </para>
+ <para>
+ Class <code><phrase role="identifier">continuation</phrase></code> provides
+ the ability for a functor to suspend itself. The functor is required to accept
+ a const reference to its own <code><phrase role="identifier">continuation</phrase></code>
+ instance.
+ </para>
+
+<programlisting><phrase role="keyword">class</phrase> <phrase role="identifier">continuation</phrase>
+<phrase role="special">{</phrase>
+<phrase role="keyword">private</phrase><phrase role="special">:</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">context</phrase> <phrase role="identifier">ctx_</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">function</phrase><phrase role="special"><</phrase> <phrase role="keyword">void</phrase><phrase role="special">(</phrase> <phrase role="identifier">continuation</phrase> <phrase role="special">&)</phrase> <phrase role="special">></phrase> <phrase role="identifier">fn_</phrase><phrase role="special">;</phrase>
+ <phrase role="keyword">bool</phrase> <phrase role="identifier">started_</phrase><phrase role="special">;</phrase>
+
+ <phrase role="keyword">void</phrase> <phrase role="identifier">trampoline_</phrase><phrase role="special">()</phrase>
+ <phrase role="special">{</phrase> <phrase role="identifier">fn_</phrase><phrase role="special">(</phrase> <phrase role="special">*</phrase> <phrase role="keyword">this</phrase><phrase role="special">);</phrase> <phrase role="special">}</phrase>
+
+<phrase role="keyword">public</phrase><phrase role="special">:</phrase>
+ <phrase role="identifier">continuation</phrase><phrase role="special">(</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">function</phrase><phrase role="special"><</phrase> <phrase role="keyword">void</phrase><phrase role="special">(</phrase> <phrase role="identifier">continuation</phrase> <phrase role="special">&)</phrase> <phrase role="special">></phrase> <phrase role="keyword">const</phrase><phrase role="special">&</phrase> <phrase role="identifier">fn</phrase><phrase role="special">)</phrase> <phrase role="special">:</phrase>
+ <phrase role="identifier">ctx_</phrase><phrase role="special">(</phrase>
+ <phrase role="special">&</phrase> <phrase role="identifier">continuation</phrase><phrase role="special">::</phrase><phrase role="identifier">trampoline_</phrase><phrase role="special">,</phrase> <phrase role="keyword">this</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">default_stacksize</phrase><phrase role="special">(),</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">no_stack_unwind</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">return_to_caller</phrase><phrase role="special">),</phrase>
+ <phrase role="keyword">false</phrase><phrase role="special">),</phrase>
+ <phrase role="identifier">fn_</phrase><phrase role="special">(</phrase> <phrase role="identifier">fn</phrase><phrase role="special">),</phrase> <phrase role="identifier">started_</phrase><phrase role="special">(</phrase> <phrase role="keyword">false</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{}</phrase>
+
+ <phrase role="keyword">void</phrase> <phrase role="identifier">resume</phrase><phrase role="special">()</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="keyword">if</phrase> <phrase role="special">(</phrase> <phrase role="special">!</phrase> <phrase role="identifier">started_</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="identifier">started_</phrase> <phrase role="special">=</phrase> <phrase role="keyword">true</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">ctx_</phrase><phrase role="special">.</phrase><phrase role="identifier">start</phrase><phrase role="special">();</phrase>
+ <phrase role="special">}</phrase>
+ <phrase role="keyword">else</phrase> <phrase role="identifier">ctx_</phrase><phrase role="special">.</phrase><phrase role="identifier">resume</phrase><phrase role="special">();</phrase>
+ <phrase role="special">}</phrase>
+
+ <phrase role="keyword">void</phrase> <phrase role="identifier">suspend</phrase><phrase role="special">()</phrase>
+ <phrase role="special">{</phrase> <phrase role="identifier">ctx_</phrase><phrase role="special">.</phrase><phrase role="identifier">suspend</phrase><phrase role="special">();</phrase> <phrase role="special">}</phrase>
+
+ <phrase role="keyword">bool</phrase> <phrase role="identifier">is_complete</phrase><phrase role="special">()</phrase> <phrase role="keyword">const</phrase>
+ <phrase role="special">{</phrase> <phrase role="keyword">return</phrase> <phrase role="identifier">ctx_</phrase><phrase role="special">.</phrase><phrase role="identifier">is_complete</phrase><phrase role="special">();</phrase> <phrase role="special">}</phrase>
+<phrase role="special">};</phrase>
+</programlisting>
+ <para>
+ The functions <code><phrase role="identifier">first</phrase><phrase role="special">()</phrase></code>
+ and <code><phrase role="identifier">second</phrase><phrase role="special">()</phrase></code>
+ are so-called coroutines running 'quasi parallel'. Please note that the variables
+ in the for-loops have local scope.
+ </para>
+
+<programlisting><phrase role="keyword">void</phrase> <phrase role="identifier">first</phrase><phrase role="special">(</phrase> <phrase role="identifier">continuation</phrase> <phrase role="special">&</phrase> <phrase role="identifier">c</phrase><phrase role="special">)</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"started first! "</phrase><phrase role="special">;</phrase>
+ <phrase role="keyword">for</phrase> <phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">i</phrase> <phrase role="special">=</phrase> <phrase role="number">0</phrase><phrase role="special">;</phrase> <phrase role="identifier">i</phrase> <phrase role="special"><</phrase> <phrase role="number">10</phrase><phrase role="special">;</phrase> <phrase role="special">++</phrase><phrase role="identifier">i</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="identifier">c</phrase><phrase role="special">.</phrase><phrase role="identifier">suspend</phrase><phrase role="special">();</phrase> <phrase role="comment">// jump back to main()
+</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"a"</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">i</phrase><phrase role="special">;</phrase> <phrase role="comment">// output
+</phrase> <phrase role="special">}</phrase>
+<phrase role="special">}</phrase>
+
+<phrase role="keyword">void</phrase> <phrase role="identifier">second</phrase><phrase role="special">(</phrase> <phrase role="identifier">continuation</phrase> <phrase role="special">&</phrase> <phrase role="identifier">c</phrase><phrase role="special">)</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"started second! "</phrase><phrase role="special">;</phrase>
+ <phrase role="keyword">for</phrase> <phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">i</phrase> <phrase role="special">=</phrase> <phrase role="number">0</phrase><phrase role="special">;</phrase> <phrase role="identifier">i</phrase> <phrase role="special"><</phrase> <phrase role="number">10</phrase><phrase role="special">;</phrase> <phrase role="special">++</phrase><phrase role="identifier">i</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="identifier">c</phrase><phrase role="special">.</phrase><phrase role="identifier">suspend</phrase><phrase role="special">();</phrase> <phrase role="comment">// jump back to main()
+</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"b"</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">i</phrase><phrase role="special">;</phrase> <phrase role="comment">// output
+</phrase> <phrase role="special">}</phrase>
+<phrase role="special">}</phrase>
+
+<phrase role="keyword">int</phrase> <phrase role="identifier">main</phrase><phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">argc</phrase><phrase role="special">,</phrase> <phrase role="keyword">char</phrase> <phrase role="special">*</phrase> <phrase role="identifier">argv</phrase><phrase role="special">[])</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="identifier">continuation</phrase> <phrase role="identifier">c1</phrase><phrase role="special">(</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">bind</phrase><phrase role="special">(</phrase> <phrase role="identifier">first</phrase><phrase role="special">,</phrase> <phrase role="identifier">_1</phrase><phrase role="special">)</phrase> <phrase role="special">);</phrase>
+ <phrase role="identifier">continuation</phrase> <phrase role="identifier">c2</phrase><phrase role="special">(</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">bind</phrase><phrase role="special">(</phrase> <phrase role="identifier">second</phrase><phrase role="special">,</phrase> <phrase role="identifier">_1</phrase><phrase role="special">)</phrase> <phrase role="special">);</phrase>
+ <phrase role="comment">// loop until coroutines c1 and c2 are complete
+</phrase> <phrase role="keyword">while</phrase> <phrase role="special">(</phrase> <phrase role="special">!</phrase> <phrase role="identifier">c1</phrase><phrase role="special">.</phrase><phrase role="identifier">is_complete</phrase><phrase role="special">()</phrase> <phrase role="special">&&</phrase> <phrase role="special">!</phrase> <phrase role="identifier">c2</phrase><phrase role="special">.</phrase><phrase role="identifier">is_complete</phrase><phrase role="special">()</phrase> <phrase role="special">)</phrase> <phrase role="special">{</phrase>
+ <phrase role="identifier">c1</phrase><phrase role="special">.</phrase><phrase role="identifier">resume</phrase><phrase role="special">();</phrase> <phrase role="comment">// call coroutine c1 -> first()
+</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">" "</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">c2</phrase><phrase role="special">.</phrase><phrase role="identifier">resume</phrase><phrase role="special">();</phrase> <phrase role="comment">// call coroutine c2 -> second()
+</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">" "</phrase><phrase role="special">;</phrase>
+ <phrase role="special">}</phrase>
+ <phrase role="special">}</phrase>
+
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"\nDone"</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+
+ <phrase role="keyword">return</phrase> <phrase role="identifier">EXIT_SUCCESS</phrase><phrase role="special">;</phrase>
+<phrase role="special">}</phrase>
+
+<phrase role="identifier">output</phrase><phrase role="special">:</phrase>
+ <phrase role="identifier">started</phrase> <phrase role="identifier">first</phrase><phrase role="special">!</phrase> <phrase role="identifier">started</phrase> <phrase role="identifier">second</phrase><phrase role="special">!</phrase> <phrase role="identifier">a0</phrase> <phrase role="identifier">b0</phrase> <phrase role="identifier">a1</phrase> <phrase role="identifier">b1</phrase> <phrase role="identifier">a2</phrase> <phrase role="identifier">b2</phrase> <phrase role="identifier">a3</phrase> <phrase role="identifier">b3</phrase> <phrase role="identifier">a4</phrase> <phrase role="identifier">b4</phrase> <phrase role="identifier">a5</phrase> <phrase role="identifier">b5</phrase> <phrase role="identifier">a6</phrase> <phrase role="identifier">b6</phrase> <phrase role="identifier">a7</phrase> <phrase role="identifier">b7</phrase> <phrase role="identifier">a8</phrase> <phrase role="identifier">b8</phrase> <phrase role="identifier">a9</phrase> <phrase role="identifier">b9</phrase>
+ <phrase role="identifier">Done</phrase>
+</programlisting>
+ </section>
+ <section id="context.examples.asio">
+ <title><link linkend="context.examples.asio">ASIO</link></title>
+ <para>
+ Adapted from <ulink url="http://blog.think-async.com/2009/08/secret-sauce-revealed.html">Thinking
+ Asynchronously in C++</ulink> using boost.asio to implement a simple echo
+ server.
+ </para>
+ <para>
+ Chris Kohlhoff uses stackless coroutines based on preprocessor-based switch
+ statements to implement an echo server using boost.asio. Class <code><phrase
+ role="identifier">continuation</phrase></code> provides a simple coroutine
+ implemenatation using boost.context.
+ </para>
+
+<programlisting><phrase role="keyword">class</phrase> <phrase role="identifier">continuation</phrase>
+<phrase role="special">{</phrase>
+<phrase role="keyword">private</phrase><phrase role="special">:</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">context</phrase> <phrase role="identifier">ctx_</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">function</phrase><phrase role="special"><</phrase> <phrase role="keyword">void</phrase><phrase role="special">(</phrase> <phrase role="identifier">continuation</phrase> <phrase role="special">&)</phrase> <phrase role="special">></phrase> <phrase role="identifier">fn_</phrase><phrase role="special">;</phrase>
+ <phrase role="keyword">bool</phrase> <phrase role="identifier">started_</phrase><phrase role="special">;</phrase>
+
+ <phrase role="keyword">void</phrase> <phrase role="identifier">trampoline_</phrase><phrase role="special">()</phrase>
+ <phrase role="special">{</phrase> <phrase role="identifier">fn_</phrase><phrase role="special">(</phrase> <phrase role="special">*</phrase> <phrase role="keyword">this</phrase><phrase role="special">);</phrase> <phrase role="special">}</phrase>
+
+<phrase role="keyword">public</phrase><phrase role="special">:</phrase>
+ <phrase role="identifier">continuation</phrase><phrase role="special">(</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">function</phrase><phrase role="special"><</phrase> <phrase role="keyword">void</phrase><phrase role="special">(</phrase> <phrase role="identifier">continuation</phrase> <phrase role="special">&)</phrase> <phrase role="special">></phrase> <phrase role="keyword">const</phrase><phrase role="special">&</phrase> <phrase role="identifier">fn</phrase><phrase role="special">)</phrase> <phrase role="special">:</phrase>
+ <phrase role="identifier">ctx_</phrase><phrase role="special">(</phrase>
+ <phrase role="special">&</phrase> <phrase role="identifier">continuation</phrase><phrase role="special">::</phrase><phrase role="identifier">trampoline_</phrase><phrase role="special">,</phrase> <phrase role="keyword">this</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">default_stacksize</phrase><phrase role="special">(),</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">no_stack_unwind</phrase><phrase role="special">,</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">contexts</phrase><phrase role="special">::</phrase><phrase role="identifier">return_to_caller</phrase><phrase role="special">),</phrase>
+ <phrase role="identifier">fn_</phrase><phrase role="special">(</phrase> <phrase role="identifier">fn</phrase><phrase role="special">),</phrase> <phrase role="identifier">started_</phrase><phrase role="special">(</phrase> <phrase role="keyword">false</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{}</phrase>
+
+ <phrase role="keyword">void</phrase> <phrase role="identifier">resume</phrase><phrase role="special">()</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="keyword">if</phrase> <phrase role="special">(</phrase> <phrase role="special">!</phrase> <phrase role="identifier">started_</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="identifier">started_</phrase> <phrase role="special">=</phrase> <phrase role="keyword">true</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">ctx_</phrase><phrase role="special">.</phrase><phrase role="identifier">start</phrase><phrase role="special">();</phrase>
+ <phrase role="special">}</phrase>
+ <phrase role="keyword">else</phrase> <phrase role="identifier">ctx_</phrase><phrase role="special">.</phrase><phrase role="identifier">resume</phrase><phrase role="special">();</phrase>
+ <phrase role="special">}</phrase>
+
+ <phrase role="keyword">void</phrase> <phrase role="identifier">suspend</phrase><phrase role="special">()</phrase>
+ <phrase role="special">{</phrase> <phrase role="identifier">ctx_</phrase><phrase role="special">.</phrase><phrase role="identifier">suspend</phrase><phrase role="special">();</phrase> <phrase role="special">}</phrase>
+
+ <phrase role="keyword">bool</phrase> <phrase role="identifier">is_complete</phrase><phrase role="special">()</phrase> <phrase role="keyword">const</phrase>
+ <phrase role="special">{</phrase> <phrase role="keyword">return</phrase> <phrase role="identifier">ctx_</phrase><phrase role="special">.</phrase><phrase role="identifier">is_complete</phrase><phrase role="special">();</phrase> <phrase role="special">}</phrase>
+<phrase role="special">};</phrase>
+</programlisting>
+ <para>
+ The operator <code><phrase role="identifier">server</phrase><phrase role="special">::</phrase><phrase
+ role="keyword">operator</phrase><phrase role="special">()</phrase></code>
+ is called by the asio reactor and jumps to coroutine (which is entering or
+ resuming in function <code><phrase role="identifier">server</phrase><phrase
+ role="special">::</phrase><phrase role="identifier">do_</phrase><phrase role="special">()</phrase></code>).
+ In function <code><phrase role="identifier">sever</phrase><phrase role="special">::</phrase><phrase
+ role="identifier">do_</phrase><phrase role="special">()</phrase></code> the
+ control flow is all in one place and easy to follow; *this is queued for
+ accepting a connection before control flow is passed back to the reactor
+ via <code><phrase role="identifier">suspend</phrase><phrase role="special">()</phrase></code>.
+ If <code><phrase role="identifier">server</phrase><phrase role="special">::</phrase><phrase
+ role="identifier">do_</phrase><phrase role="special">()</phrase></code> is
+ reentered, a local buffer is created and an asynch. read operation is queued
+ into the reactor. The control flow is then returned to the reactor for io-multiplexing
+ again. After some bytes were received <code><phrase role="identifier">server</phrase><phrase
+ role="special">::</phrase><phrase role="identifier">do_</phrase><phrase role="special">()</phrase></code>
+ is reentred again starting a asynch. write operation.
+ </para>
+ <para>
+ The advantage over the ordinary <code><phrase role="identifier">bind</phrase><phrase
+ role="special">()</phrase></code> version is that the state of execution
+ is preserved so that variables used by the read/write operations may have
+ local scope. Stackfull coroutines (as boost.context provides) enable application-protocol
+ stacks which can be more easily implemented. For instance, if only part of
+ a message is received (some bytes are outstanding before message can be parsed
+ or serviced), then the current state can be easily suspended/preserved (even
+ from nested functions of the protocol stack) until the remaining bytes are
+ received.
+ </para>
+
+<programlisting><phrase role="keyword">class</phrase> <phrase role="identifier">server</phrase> <phrase role="special">:</phrase> <phrase role="keyword">public</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">enable_shared_from_this</phrase><phrase role="special"><</phrase> <phrase role="identifier">server</phrase> <phrase role="special">>,</phrase>
+ <phrase role="keyword">private</phrase> <phrase role="identifier">continuation</phrase>
+<phrase role="special">{</phrase>
+<phrase role="keyword">private</phrase><phrase role="special">:</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">asio</phrase><phrase role="special">::</phrase><phrase role="identifier">ip</phrase><phrase role="special">::</phrase><phrase role="identifier">tcp</phrase><phrase role="special">::</phrase><phrase role="identifier">acceptor</phrase> <phrase role="identifier">acceptor_</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">system</phrase><phrase role="special">::</phrase><phrase role="identifier">error_code</phrase> <phrase role="identifier">ec_</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">size_t</phrase> <phrase role="identifier">n_</phrase><phrase role="special">;</phrase>
+
+ <phrase role="keyword">void</phrase> <phrase role="identifier">do_</phrase><phrase role="special">()</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="keyword">for</phrase> <phrase role="special">(;;)</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">asio</phrase><phrase role="special">::</phrase><phrase role="identifier">ip</phrase><phrase role="special">::</phrase><phrase role="identifier">tcp</phrase><phrase role="special">::</phrase><phrase role="identifier">socket</phrase> <phrase role="identifier">socket</phrase><phrase role="special">(</phrase> <phrase role="identifier">acceptor_</phrase><phrase role="special">.</phrase><phrase role="identifier">get_io_service</phrase><phrase role="special">()</phrase> <phrase role="special">);</phrase>
+ <phrase role="comment">// accept connection request and enque *this for reading data from conenction
+</phrase> <phrase role="identifier">acceptor_</phrase><phrase role="special">.</phrase><phrase role="identifier">async_accept</phrase><phrase role="special">(</phrase> <phrase role="identifier">socket</phrase><phrase role="special">,</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">bind</phrase><phrase role="special">(</phrase> <phrase role="special">&</phrase> <phrase role="identifier">server</phrase><phrase role="special">::</phrase><phrase role="keyword">operator</phrase><phrase role="special">(),</phrase> <phrase role="keyword">this</phrase><phrase role="special">-></phrase><phrase role="identifier">shared_from_this</phrase><phrase role="special">(),</phrase> <phrase role="identifier">_1</phrase><phrase role="special">,</phrase> <phrase role="number">0</phrase><phrase role="special">)</phrase> <phrase role="special">);</phrase>
+ <phrase role="comment">// suspend() jumps back to operator() which returns to asio reactor
+</phrase> <phrase role="identifier">suspend</phrase><phrase role="special">();</phrase>
+
+ <phrase role="keyword">while</phrase> <phrase role="special">(</phrase> <phrase role="special">!</phrase> <phrase role="identifier">ec_</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="comment">// buffer has local scope!
+</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">array</phrase><phrase role="special"><</phrase> <phrase role="keyword">char</phrase><phrase role="special">,</phrase> <phrase role="number">1024</phrase> <phrase role="special">></phrase> <phrase role="identifier">buffer</phrase><phrase role="special">;</phrase>
+
+ <phrase role="comment">// enqueue *this to read some bytes from the connection into buffer
+</phrase> <phrase role="identifier">socket</phrase><phrase role="special">.</phrase><phrase role="identifier">async_read_some</phrase><phrase role="special">(</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">asio</phrase><phrase role="special">::</phrase><phrase role="identifier">buffer</phrase><phrase role="special">(</phrase> <phrase role="identifier">buffer</phrase><phrase role="special">),</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">bind</phrase><phrase role="special">(</phrase> <phrase role="special">&</phrase> <phrase role="identifier">server</phrase><phrase role="special">::</phrase><phrase role="keyword">operator</phrase><phrase role="special">(),</phrase> <phrase role="keyword">this</phrase><phrase role="special">-></phrase><phrase role="identifier">shared_from_this</phrase><phrase role="special">(),</phrase> <phrase role="identifier">_1</phrase><phrase role="special">,</phrase> <phrase role="identifier">_2</phrase><phrase role="special">)</phrase> <phrase role="special">);</phrase>
+ <phrase role="comment">// suspend() jumps back to operator(); asio reactor
+</phrase> <phrase role="identifier">suspend</phrase><phrase role="special">();</phrase>
+
+ <phrase role="comment">// finish and return
+</phrase> <phrase role="keyword">if</phrase> <phrase role="special">(</phrase> <phrase role="identifier">ec_</phrase><phrase role="special">)</phrase> <phrase role="keyword">break</phrase><phrase role="special">;</phrase>
+
+ <phrase role="comment">// enqueue *this to write data from buffer to connection
+</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">asio</phrase><phrase role="special">::</phrase><phrase role="identifier">async_write</phrase><phrase role="special">(</phrase>
+ <phrase role="identifier">socket</phrase><phrase role="special">,</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">asio</phrase><phrase role="special">::</phrase><phrase role="identifier">buffer</phrase><phrase role="special">(</phrase> <phrase role="identifier">buffer</phrase><phrase role="special">,</phrase> <phrase role="identifier">n_</phrase><phrase role="special">),</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">bind</phrase><phrase role="special">(</phrase> <phrase role="special">&</phrase> <phrase role="identifier">server</phrase><phrase role="special">::</phrase><phrase role="keyword">operator</phrase><phrase role="special">(),</phrase> <phrase role="keyword">this</phrase><phrase role="special">-></phrase><phrase role="identifier">shared_from_this</phrase><phrase role="special">(),</phrase> <phrase role="identifier">_1</phrase><phrase role="special">,</phrase> <phrase role="identifier">_2</phrase><phrase role="special">)</phrase> <phrase role="special">);</phrase>
+ <phrase role="comment">// suspend() jumps back to operator(); asio reactor
+</phrase> <phrase role="identifier">suspend</phrase><phrase role="special">();</phrase>
+ <phrase role="special">}</phrase>
+ <phrase role="special">}</phrase>
+ <phrase role="special">}</phrase>
+
+ <phrase role="identifier">server</phrase><phrase role="special">(</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">asio</phrase><phrase role="special">::</phrase><phrase role="identifier">io_service</phrase> <phrase role="special">&</phrase> <phrase role="identifier">io_service</phrase><phrase role="special">,</phrase> <phrase role="keyword">short</phrase> <phrase role="identifier">port</phrase><phrase role="special">)</phrase> <phrase role="special">:</phrase>
+ <phrase role="identifier">continuation</phrase><phrase role="special">(</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">bind</phrase><phrase role="special">(</phrase> <phrase role="special">&</phrase> <phrase role="identifier">server</phrase><phrase role="special">::</phrase><phrase role="identifier">do_</phrase><phrase role="special">,</phrase> <phrase role="keyword">this</phrase><phrase role="special">)</phrase> <phrase role="special">),</phrase>
+ <phrase role="identifier">acceptor_</phrase><phrase role="special">(</phrase> <phrase role="identifier">io_service</phrase><phrase role="special">,</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">asio</phrase><phrase role="special">::</phrase><phrase role="identifier">ip</phrase><phrase role="special">::</phrase><phrase role="identifier">tcp</phrase><phrase role="special">::</phrase><phrase role="identifier">endpoint</phrase><phrase role="special">(</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">asio</phrase><phrase role="special">::</phrase><phrase role="identifier">ip</phrase><phrase role="special">::</phrase><phrase role="identifier">tcp</phrase><phrase role="special">::</phrase><phrase role="identifier">v4</phrase><phrase role="special">(),</phrase> <phrase role="identifier">port</phrase><phrase role="special">)</phrase> <phrase role="special">),</phrase>
+ <phrase role="identifier">ec_</phrase><phrase role="special">(),</phrase> <phrase role="identifier">n_</phrase><phrase role="special">(</phrase> <phrase role="number">0</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{}</phrase>
+
+<phrase role="keyword">public</phrase><phrase role="special">:</phrase>
+ <phrase role="keyword">typedef</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">shared_ptr</phrase><phrase role="special"><</phrase> <phrase role="identifier">server</phrase> <phrase role="special">></phrase> <phrase role="identifier">ptr_t</phrase><phrase role="special">;</phrase>
+
+ <phrase role="keyword">static</phrase> <phrase role="identifier">ptr_t</phrase> <phrase role="identifier">create</phrase><phrase role="special">(</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">asio</phrase><phrase role="special">::</phrase><phrase role="identifier">io_service</phrase> <phrase role="special">&</phrase> <phrase role="identifier">io_service</phrase><phrase role="special">,</phrase> <phrase role="keyword">short</phrase> <phrase role="identifier">port</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{</phrase> <phrase role="keyword">return</phrase> <phrase role="identifier">ptr_t</phrase><phrase role="special">(</phrase> <phrase role="keyword">new</phrase> <phrase role="identifier">server</phrase><phrase role="special">(</phrase> <phrase role="identifier">io_service</phrase><phrase role="special">,</phrase> <phrase role="identifier">port</phrase><phrase role="special">)</phrase> <phrase role="special">);</phrase> <phrase role="special">}</phrase>
+
+ <phrase role="keyword">void</phrase> <phrase role="keyword">operator</phrase><phrase role="special">()(</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">system</phrase><phrase role="special">::</phrase><phrase role="identifier">error_code</phrase> <phrase role="identifier">ec</phrase><phrase role="special">,</phrase> <phrase role="identifier">size_t</phrase> <phrase role="identifier">n</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="identifier">ec_</phrase> <phrase role="special">=</phrase> <phrase role="identifier">ec</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">n_</phrase> <phrase role="special">=</phrase> <phrase role="identifier">n</phrase><phrase role="special">;</phrase>
+ <phrase role="comment">// jump to coroutine (do_())
+</phrase> <phrase role="identifier">resume</phrase><phrase role="special">();</phrase>
+ <phrase role="special">}</phrase>
+<phrase role="special">};</phrase>
+
+<phrase role="keyword">int</phrase> <phrase role="identifier">main</phrase><phrase role="special">(</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">argc</phrase><phrase role="special">,</phrase> <phrase role="keyword">char</phrase> <phrase role="special">*</phrase> <phrase role="identifier">argv</phrase><phrase role="special">[])</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="keyword">try</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="keyword">if</phrase> <phrase role="special">(</phrase> <phrase role="identifier">argc</phrase> <phrase role="special">!=</phrase> <phrase role="number">2</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cerr</phrase> <phrase role="special"><<</phrase> <phrase role="string">"Usage: echo_server <port>\n"</phrase><phrase role="special">;</phrase>
+ <phrase role="keyword">return</phrase> <phrase role="number">1</phrase><phrase role="special">;</phrase>
+ <phrase role="special">}</phrase>
+ <phrase role="special">{</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">asio</phrase><phrase role="special">::</phrase><phrase role="identifier">io_service</phrase> <phrase role="identifier">io_service</phrase><phrase role="special">;</phrase>
+ <phrase role="identifier">io_service</phrase><phrase role="special">.</phrase><phrase role="identifier">post</phrase><phrase role="special">(</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">bind</phrase><phrase role="special">(</phrase>
+ <phrase role="special">&</phrase> <phrase role="identifier">server</phrase><phrase role="special">::</phrase><phrase role="keyword">operator</phrase><phrase role="special">(),</phrase>
+ <phrase role="identifier">server</phrase><phrase role="special">::</phrase><phrase role="identifier">create</phrase><phrase role="special">(</phrase> <phrase role="identifier">io_service</phrase><phrase role="special">,</phrase> <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">lexical_cast</phrase><phrase role="special"><</phrase> <phrase role="keyword">short</phrase> <phrase role="special">>(</phrase> <phrase role="identifier">argv</phrase><phrase role="special">[</phrase><phrase role="number">1</phrase><phrase role="special">])</phrase> <phrase role="special">),</phrase>
+ <phrase role="identifier">boost</phrase><phrase role="special">::</phrase><phrase role="identifier">system</phrase><phrase role="special">::</phrase><phrase role="identifier">error_code</phrase><phrase role="special">(),</phrase> <phrase role="number">0</phrase><phrase role="special">)</phrase> <phrase role="special">);</phrase>
+ <phrase role="identifier">io_service</phrase><phrase role="special">.</phrase><phrase role="identifier">run</phrase><phrase role="special">();</phrase>
+ <phrase role="special">}</phrase>
+ <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cout</phrase> <phrase role="special"><<</phrase> <phrase role="string">"Done"</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase>
+
+ <phrase role="keyword">return</phrase> <phrase role="identifier">EXIT_SUCCESS</phrase><phrase role="special">;</phrase>
+ <phrase role="special">}</phrase>
+ <phrase role="keyword">catch</phrase> <phrase role="special">(</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">exception</phrase> <phrase role="keyword">const</phrase><phrase role="special">&</phrase> <phrase role="identifier">e</phrase><phrase role="special">)</phrase>
+ <phrase role="special">{</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">cerr</phrase> <phrase role="special"><<</phrase> <phrase role="string">"Exception: "</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">e</phrase><phrase role="special">.</phrase><phrase role="identifier">what</phrase><phrase role="special">()</phrase> <phrase role="special"><<</phrase> <phrase role="identifier">std</phrase><phrase role="special">::</phrase><phrase role="identifier">endl</phrase><phrase role="special">;</phrase> <phrase role="special">}</phrase>
+
+ <phrase role="keyword">return</phrase> <phrase role="identifier">EXIT_FAILURE</phrase><phrase role="special">;</phrase>
+<phrase role="special">}</phrase>
+</programlisting>
+ </section>
+ </section>
+ <section id="context.performance">
+ <title><link linkend="context.performance">Performance</link></title>
+ <para>
+ Performance of <emphasis role="bold">Boost.Context</emphasis> was measured
+ on the platforms shown in the following table. Performance measurements were
+ taken using <code><phrase role="identifier">rdtsc</phrase></code>, with overhead
+ corrections, on x86 platforms. In each case, stack protection was active, cache
+ warm-up was accounted for, and the one running thread was pinned to a single
+ CPU. The code was compiled using the build options, 'variant<literal>release
+ cxxflags</literal>-DBOOST_DISABLE_ASSERTS'.
+ </para>
+ <para>
+ The numbers in the table are the number of cycles per iteration, based upon
+ an average computed over 1000 iterations.
+ </para>
+ <table frame="all">
+ <title>Perfomance of context switch</title>
+ <tgroup cols="3">
+ <thead>
+ <row>
+ <entry>
+ <para>
+ Platform
+ </para>
+ </entry>
+ <entry>
+ <para>
+ ucontext_t
+ </para>
+ </entry>
+ <entry>
+ <para>
+ fcontext_t
+ </para>
+ </entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>
+ <para>
+ AMD Athlon 64 DualCore 4400+ (32bit Linux)
+ </para>
+ </entry>
+ <entry>
+ <para>
+ 1771 cycles
+ </para>
+ </entry>
+ <entry>
+ <para>
+ 146 cycles
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>
+ <para>
+ Intel Core2 Quad (64bit Linux)
+ </para>
+ </entry>
+ <entry>
+ <para>
+ 1739 cycles
+ </para>
+ </entry>
+ <entry>
+ <para>
+ 117 cycles
+ </para>
+ </entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </section>
+ <section id="context.tested">
+ <title><link linkend="context.tested">Tested Platforms</link></title>
+ <informaltable frame="all">
+ <tgroup cols="4">
+ <thead>
+ <row>
+ <entry>
+ <para>
+ Platform
+ </para>
+ </entry>
+ <entry>
+ <para>
+ OS
+ </para>
+ </entry>
+ <entry>
+ <para>
+ Compiler
+ </para>
+ </entry>
+ <entry>
+ <para>
+ ABI
+ </para>
+ </entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>
+ <para>
+ ARM (ARM926EJ-S)
+ </para>
+ </entry>
+ <entry>
+ <para>
+ Debian GNU/Linux (Lenny)
+ </para>
+ </entry>
+ <entry>
+ <para>
+ GCC 4.4.4
+ </para>
+ </entry>
+ <entry>
+ <para>
+ ARM APCS (Linux)
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>
+ <para>
+ MIPS (MIPS 24K)
+ </para>
+ </entry>
+ <entry>
+ <para>
+ Debian GNU/Linux (Lenny)
+ </para>
+ </entry>
+ <entry>
+ <para>
+ GCC 4.3.2
+ </para>
+ </entry>
+ <entry>
+ <para>
+ O32
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>
+ <para>
+ MIPS (O2 / MIPS R5000)
+ </para>
+ </entry>
+ <entry>
+ <para>
+ Debian GNU/Linux (Lenny)
+ </para>
+ </entry>
+ <entry>
+ <para>
+ GCC 4.3.2
+ </para>
+ </entry>
+ <entry>
+ <para>
+ O32
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>
+ <para>
+ PowerPC (7400)
+ </para>
+ </entry>
+ <entry>
+ <para>
+ Debian GNU/Linux (Lenny)
+ </para>
+ </entry>
+ <entry>
+ <para>
+ GCC 4.3.2
+ </para>
+ </entry>
+ <entry>
+ <para>
+ SYSV
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>
+ <para>
+ X86_64 (Intel Core2 Quad)
+ </para>
+ </entry>
+ <entry>
+ <para>
+ Ubuntu GNU/Linux (Lucid Lynx)
+ </para>
+ </entry>
+ <entry>
+ <para>
+ GCC 4.4.3
+ </para>
+ </entry>
+ <entry>
+ <para>
+ SYSV
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>
+ <para>
+ X86_64
+ </para>
+ </entry>
+ <entry>
+ <para>
+ Windows 7
+ </para>
+ </entry>
+ <entry>
+ <para>
+ MS VC 10.0
+ </para>
+ </entry>
+ <entry>
+ <para>
+ PE
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>
+ <para>
+ I386
+ </para>
+ </entry>
+ <entry>
+ <para>
+ Debian GNU/Linux (Lenny)
+ </para>
+ </entry>
+ <entry>
+ <para>
+ GCC 4.4.3
+ </para>
+ </entry>
+ <entry>
+ <para>
+ SYSV
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>
+ <para>
+ I386
+ </para>
+ </entry>
+ <entry>
+ <para>
+ FreeBSD 8.0
+ </para>
+ </entry>
+ <entry>
+ <para>
+ GCC 4.2.1
+ </para>
+ </entry>
+ <entry>
+ <para>
+ SYSV
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>
+ <para>
+ I386
+ </para>
+ </entry>
+ <entry>
+ <para>
+ OpenSolaris 2009.06
+ </para>
+ </entry>
+ <entry>
+ <para>
+ GCC 4.3.2
+ </para>
+ </entry>
+ <entry>
+ <para>
+ SYSV
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>
+ <para>
+ I386
+ </para>
+ </entry>
+ <entry>
+ <para>
+ Windows XP
+ </para>
+ </entry>
+ <entry>
+ <para>
+ MSVC 9.0
+ </para>
+ </entry>
+ <entry>
+ <para>
+ PE
+ </para>
+ </entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </informaltable>
+ </section>
+ <section id="context.rationale">
+ <title><link linkend="context.rationale">Rationale</link></title> <anchor id="context.rationale.nothrow_guarantee"/>
+ <bridgehead renderas="sect3">
+ <link linkend="context.rationale.nothrow_guarantee">NoThrow guarantee</link>
+ </bridgehead>
+ <para>
+ Member functions of <link linkend="context.context.context"><emphasis>context</emphasis></link>
+ do not thow exceptions but do require that certain preconditions are satisifed:
+ context jumps can only be made by instances which are not a <emphasis>not-a-context</emphasis>
+ and which are not complete.
+ </para>
+ <anchor id="context.rationale.pimpl_idiom"/>
+ <bridgehead renderas="sect3">
+ <link linkend="context.rationale.pimpl_idiom">Pimpl idiom</link>
+ </bridgehead>
+ <para>
+ In order to support move semantics and context switching operations, the use
+ of the Pimpl Idiom was necessary. A nice feature is that a <link linkend="context.context.context"><emphasis>context</emphasis></link>
+ has the size of a pointer, so it fits into a register.
+ </para>
+ <para>
+ With the current design the constructor accepts functors and its arguments
+ similiar to <emphasis>thread</emphasis>.
+ </para>
+ <para>
+ The Pimpl Idiom allows type-erasing the <emphasis>StackAllocator</emphasis>
+ type.
+ </para>
+ <anchor id="context.rationale.unwinding"/>
+ <bridgehead renderas="sect3">
+ <link linkend="context.rationale.unwinding">Unwinding</link>
+ </bridgehead>
+ <para>
+ In order to release resources allocated on the stack, unwinding the stack must
+ be supported. The current implementation throws a exception in order to unwind
+ the stack (jump back to invocation of <code><phrase role="identifier">suspend</phrase><phrase
+ role="special">()</phrase></code>). The special exception is caught inside
+ the trampoline function (first function on top of stack).
+ </para>
+ <anchor id="context.rationale.protecting_the_stack"/>
+ <bridgehead renderas="sect3">
+ <link linkend="context.rationale.protecting_the_stack">Protecting the stack</link>
+ </bridgehead>
+ <para>
+ Because the stack's size is fixed -- there is no support for split stacks --
+ it is important to protect against exceeding the stack's bounds. Otherwise,
+ in the best case, overrunning the stack's memory will result in a segmentation
+ fault or access violation and, in the worst case, the application's memory
+ will be overwritten. <code><phrase role="identifier">stack_allocator</phrase></code>
+ appends a guard page to the stack to help detect overruns. The guard page consumes
+ no physical memory, but generates a segmentation fault or access violation
+ on access to the virtual memory addresses within it.
+ </para>
+ <anchor id="context.rationale.fcontext_t"/>
+ <bridgehead renderas="sect3">
+ <link linkend="context.rationale.fcontext_t">fcontext_t</link>
+ </bridgehead>
+ <para>
+ <emphasis role="bold">Boost.Context</emphasis> provides the low leve lAPI boost_fcontext_t
+ which is implemented in assembler to provide context swapping operations. boost_fcontext_t
+ is the part to port to new platforms.
+ </para>
+ <note>
+ <para>
+ Context switches do not preserve the signal mask on UNIX systems.
+ </para>
+ </note>
+ <section id="context.rationale.other_apis_">
+ <title><link linkend="context.rationale.other_apis_">Other APIs </link></title>
+ <anchor id="context.rationale.other_apis_.setjmp___longjmp__"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.rationale.other_apis_.setjmp___longjmp__">setjmp()/longjmp()</link>
+ </bridgehead>
+ <para>
+ C99 defines <code><phrase role="identifier">setjmp</phrase><phrase role="special">()</phrase></code>/<code><phrase
+ role="identifier">longjmp</phrase><phrase role="special">()</phrase></code>
+ to provide non-local jumps but it does not require that <emphasis>longjmp()</emphasis>
+ preserves the current stack frame. Therefore, jumping into a function which
+ was exited via a call to <emphasis>longjmp()</emphasis> is undefined <footnote>
+ <para>
+ <ulink url="boost:/libs/context/doc/pdf/iso_c99.pdf">ISO/IEC 9899:1999,
+ 2005</ulink>, 7.13.2.1:2
+ </para>
+ </footnote>.
+ </para>
+ <anchor id="context.rationale.other_apis_.ucontext_t"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.rationale.other_apis_.ucontext_t">ucontext_t</link>
+ </bridgehead>
+ <para>
+ Since POSIX.1-2003 <code><phrase role="identifier">ucontext_t</phrase></code>
+ is deprecated and was removed in POSIX.1-2008! The function signature of
+ <code><phrase role="identifier">makecontext</phrase><phrase role="special">()</phrase></code>
+ is:
+ </para>
+
+<programlisting><phrase role="keyword">void</phrase> <phrase role="identifier">makecontext</phrase><phrase role="special">(</phrase><phrase role="identifier">ucontext_t</phrase> <phrase role="special">*</phrase><phrase role="identifier">ucp</phrase><phrase role="special">,</phrase> <phrase role="keyword">void</phrase> <phrase role="special">(*</phrase><phrase role="identifier">func</phrase><phrase role="special">)(),</phrase> <phrase role="keyword">int</phrase> <phrase role="identifier">argc</phrase><phrase role="special">,</phrase> <phrase role="special">...);</phrase>
+</programlisting>
+ <para>
+ The third argument of <code><phrase role="identifier">makecontext</phrase><phrase
+ role="special">()</phrase></code> specifies the number of integer arguments
+ that follow which will require function pointer cast if <code><phrase role="identifier">func</phrase></code>
+ will accept those arguments which is undefined in C99 <footnote>
+ <para>
+ <ulink url="boost:/libs/context/doc/pdf/iso_c99.pdf">ISO/IEC 9899:1999,
+ 2005</ulink>, J.2
+ </para>
+ </footnote>.
+ </para>
+ <para>
+ The arguments in the var-arg list are required to be integers, passing pointers
+ in var-arg list is not guarantied to work, especially it will fail for architectures
+ where pointers are larger than integers.
+ </para>
+ <para>
+ <code><phrase role="identifier">ucontext_t</phrase></code> preserves signal
+ mask between context switches which involes system calls consuming a lot
+ of CPU cycles (ucontext_t is slower by perfomance_link[factor 13x] relative
+ to <code><phrase role="identifier">boost_fcontext_t</phrase></code>).
+ </para>
+ <anchor id="context.rationale.other_apis_.windows_fibers"/>
+ <bridgehead renderas="sect4">
+ <link linkend="context.rationale.other_apis_.windows_fibers">Windows fibers</link>
+ </bridgehead>
+ <para>
+ A drawback of Windows Fiber API is that <code><phrase role="identifier">CreateFiber</phrase><phrase
+ role="special">()</phrase></code> does not accept a pointer to user allocated
+ stack space preventing the reuse of stacks for other context instances. Because
+ the Windows Fiber API requires to call <code><phrase role="identifier">ConvertThreadToFiber</phrase><phrase
+ role="special">()</phrase></code> if <code><phrase role="identifier">SwitchFiber</phrase><phrase
+ role="special">()</phrase></code> is called for a thread which has not been
+ converted to a fiber. For the same reason <code><phrase role="identifier">ConvertFiberToThread</phrase><phrase
+ role="special">()</phrase></code> must be called after return from <code><phrase
+ role="identifier">SwitchFiber</phrase><phrase role="special">()</phrase></code>
+ if the thread was forced to be converted to a fiber before (which is inefficient).
+ </para>
+
+<programlisting><phrase role="keyword">if</phrase> <phrase role="special">(</phrase> <phrase role="special">!</phrase> <phrase role="identifier">is_a_fiber</phrase><phrase role="special">()</phrase> <phrase role="special">)</phrase>
+<phrase role="special">{</phrase>
+ <phrase role="identifier">ConvertThreadToFiber</phrase><phrase role="special">(</phrase> <phrase role="number">0</phrase><phrase role="special">);</phrase>
+ <phrase role="identifier">SwitchToFiber</phrase><phrase role="special">(</phrase> <phrase role="identifier">ctx</phrase><phrase role="special">);</phrase>
+ <phrase role="identifier">ConvertFiberToThread</phrase><phrase role="special">();</phrase>
+<phrase role="special">}</phrase>
+</programlisting>
+ <para>
+ If the condition <code><phrase role="identifier">_WIN32_WINNT</phrase> <phrase
+ role="special">>=</phrase> <phrase role="identifier">_WIN32_WINNT_VISTA</phrase></code>
+ is met function <code><phrase role="identifier">IsThreadAFiber</phrase><phrase
+ role="special">()</phrase></code> is provided in order to detect if the current
+ thread was already converted. Unfortunately Windows XP + SP 2/3 defines
+ <code><phrase role="identifier">_WIN32_WINNT</phrase> <phrase role="special">>=</phrase>
+ <phrase role="identifier">_WIN32_WINNT_VISTA</phrase></code> without providing
+ <code><phrase role="identifier">IsThreadAFiber</phrase><phrase role="special">()</phrase></code>.
+ </para>
+ </section>
+ </section>
+ <section id="context.reference">
+ <title><link linkend="context.reference">Reference</link></title> <anchor id="context.reference.arm"/>
+ <bridgehead renderas="sect3">
+ <link linkend="context.reference.arm">ARM</link>
+ </bridgehead>
+ <itemizedlist>
+ <listitem>
+ <simpara>
+ AAPCS ABI: <ulink url="boost:/libs/context/doc/pdf/arm-aapcs.pdf">Procedure
+ Call Standard for the ARM Architecture</ulink>
+ </simpara>
+ </listitem>
+ <listitem>
+ <simpara>
+ AAPCS/LINUX: <ulink url="boost:/libs/context/doc/pdf/arm-linux-aapcs.pdf">ARM
+ GNU/Linux Application Binary Interface Supplement</ulink>
+ </simpara>
+ </listitem>
+ </itemizedlist>
+ <anchor id="context.reference.mips"/>
+ <bridgehead renderas="sect3">
+ <link linkend="context.reference.mips">MIPS</link>
+ </bridgehead>
+ <itemizedlist>
+ <listitem>
+ <simpara>
+ O32 ABI: <ulink url="boost:/libs/context/doc/pdf/mips-o32.pdf">SYSTEM V
+ APPLICATION BINARY INTERFACE, MIPS RISC Processor Supplement</ulink>
+ </simpara>
+ </listitem>
+ </itemizedlist>
+ <anchor id="context.reference.powerpc32"/>
+ <bridgehead renderas="sect3">
+ <link linkend="context.reference.powerpc32">PowerPC32</link>
+ </bridgehead>
+ <itemizedlist>
+ <listitem>
+ <simpara>
+ SYSV ABI: <ulink url="boost:/libs/context/doc/pdf/ppc32-sysv.pdf">SYSTEM
+ V APPLICATION BINARY INTERFACE PowerPC Processor Supplement</ulink>
+ </simpara>
+ </listitem>
+ </itemizedlist>
+ <anchor id="context.reference.powerpc64"/>
+ <bridgehead renderas="sect3">
+ <link linkend="context.reference.powerpc64">PowerPC64</link>
+ </bridgehead>
+ <itemizedlist>
+ <listitem>
+ <simpara>
+ SYSV ABI: <ulink url="boost:/libs/context/doc/pdf/ppc64-sysv.pdf">PowerPC
+ User Instruction Set Architecture, Book I</ulink>
+ </simpara>
+ </listitem>
+ </itemizedlist>
+ <anchor id="context.reference.x86_32"/>
+ <bridgehead renderas="sect3">
+ <link linkend="context.reference.x86_32">X86-32</link>
+ </bridgehead>
+ <itemizedlist>
+ <listitem>
+ <simpara>
+ SYSV ABI: <ulink url="boost:/libs/context/doc/pdf/x86_32-sysv.pdf">SYSTEM
+ V APPLICATION BINARY INTERFACE, Intel386TM Architecture Processor Supplement</ulink>
+ </simpara>
+ </listitem>
+ <listitem>
+ <simpara>
+ MS PE: <ulink url="http://msdn.microsoft.com/en-us/library/k2b2ssfy.aspx">Calling
+ Conventions</ulink>
+ </simpara>
+ </listitem>
+ </itemizedlist>
+ <anchor id="context.reference.x86_64"/>
+ <bridgehead renderas="sect3">
+ <link linkend="context.reference.x86_64">X86-64</link>
+ </bridgehead>
+ <itemizedlist>
+ <listitem>
+ <simpara>
+ SYSV ABI: <ulink url="boost:/libs/context/doc/pdf/x86_64-sysv.pdf">System
+ V Application Binary Interface, AMD64 Architecture Processor Supplement</ulink>
+ </simpara>
+ </listitem>
+ <listitem>
+ <simpara>
+ MS PE: <ulink url="http://msdn.microsoft.com/en-us/library/7kcdt6fy%28VS.80%29.aspx">x64
+ Software Conventions</ulink>
+ </simpara>
+ </listitem>
+ </itemizedlist>
+ </section>
+ <section id="context.todo">
+ <title><link linkend="context.todo">Todo</link></title>
+ <itemizedlist>
+ <listitem>
+ <simpara>
+ provide support for SPARC
+ </simpara>
+ </listitem>
+ </itemizedlist>
+ </section>
+ <section id="context.acknowledgements">
+ <title><link linkend="context.acknowledgements">Acknowledgments</link></title>
+ <para>
+ I'd like to thank Adreas Fett, Artyom Beilis, Fernando Pelliccioni, Giovanni
+ Piero Deretta, Gordon Woodhull, Helge Bahmann, Holger Grund, Jeffrey Lee Hellrung
+ (Jr.), Keith Jeffery, Phil Endecott, Robert Stewart, Vicente J. Botet Escriba.
+ </para>
+ </section>
+</article>

Added: trunk/libs/context/doc/context_ref.qbk
==============================================================================
--- (empty file)
+++ trunk/libs/context/doc/context_ref.qbk 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,753 @@
+[/
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt
+]
+
+[section:context Context]
+
+Each instance of __context__ represents a context (CPU registers and stack
+space) of execution or __not_a_context__. Objects of type __context__ are
+moveable but not copyable and can be returned by a function.
+
+ boost::contexts::context make_context();
+
+ void f()
+ {
+ boost::contexts::context ctx( make_context() );
+ ctx.resume();
+ }
+
+[note __boost_move__ is used to emulate rvalue references.]
+
+[warning If contexts are used in a multithreaded application, they can migrated
+between threads, but must not reference __tls__.]
+
+[note If __fls__ is used on Windows, the user is responsible for calling
+__fls_alloc__, __fls_free__.]
+
+
+[heading Executing a context]
+
+A new context is created from a callable object (known as the __context_fn__).
+The stack size, stack unwinding behavior, and context termination behavior are
+determined by additional arguments.
+
+The __context__ constructor uses a __stack_allocator_concept__ to allocate an
+associated stack, and the destructor uses the same __stack_allocator_concept__
+to deallocate the stack. The default __stack_allocator_concept__ is
+__stack_allocator__, but a custom stack-allocator can be passed to the
+constructor.
+
+Additional arguments needed by a __context_fn__ are supplied as additional
+arguments to the context constructor.
+
+ void f( int i);
+
+ boost::contexts::context ctx( f, 42,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind,
+ boost::contexts::return_to_caller);
+
+The __context_fn__, as well as its arguments, if any, are copied into the
+context's state. If a reference is required, use boost::ref.
+
+The maximum number of arguments of __context_fn__ is defined by
+BOOST_CONTEXT_ARITY (default is 10 and might be increased).
+
+Calling __context_start__ invokes the __context_fn__ in a newly created context
+complete with registers, flags, stack and instruction pointers. When control
+should be returned to the original calling context, call __context_suspend__.
+The current context information (registers, flags, and stack and instruction
+pointers) is saved and the original context information is restored. Calling
+__context_resume__ resumes execution in the second context after saving the new
+state of the original context.
+Note that __context_start__ must be called first and only once.
+
+ boost::contexts::context ctx;
+
+ void fn( int j)
+ {
+ for( int i = 0; i < j; ++i)
+ {
+ std::cout << "fn(): local variable i == " << i << std::endl;
+
+ // save current context
+ // value of local variable is preserved
+ // transfer execution control back to main()
+ ctx.suspend();
+
+ // ctx.resume() was called
+ // execution control transfered back from main()
+ }
+ }
+
+ int main( int argc, char * argv[])
+ {
+ ctx = boost::contexts::context( fn, 7,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind,
+ boost::contexts::return_to_caller);
+
+ std::cout << "main() starts context ctx" << std::endl;
+ // start the context ctx for the first time; enter fn()
+ ctx.start();
+
+ // ctx.suspend() was called so we returned from start()
+ while ( ! ctx.is_complete() )
+ {
+ std::cout << "main() calls context ctx" << std::endl;
+ // resume inside fn()
+ // execution control is transfered to ctx
+ ctx.resume();
+
+ // ctx.suspend() was called within fn()
+ }
+
+ std::cout << "Done" << std::endl;
+
+ return EXIT_SUCCESS;
+ }
+
+ output:
+ main() starts context ctx
+ fn(): local variable i == 0
+ main() calls context ctx
+ fn(): local variable i == 1
+ main() calls context ctx
+ fn(): local variable i == 2
+ main() calls context ctx
+ fn(): local variable i == 3
+ main() calls context ctx
+ fn(): local variable i == 4
+ main() calls context ctx
+ fn(): local variable i == 5
+ main() calls context ctx
+ fn(): local variable i == 6
+ main() calls context ctx
+ Done
+
+[warning Calling __context_resume__ from inside the same context results in
+undefined behaviour.]
+
+[note In contrast to threads, which are preemtive, __context__ switches are
+cooperative (programmer controls when switch will happen). The kernel is not
+involved in the context switches.]
+
+
+[heading Transfer of data]
+
+The argument passed to __context_resume__, in one context, is returned by
+__context_suspend__ in the other context. The intptr_t passed to
+__context_suspend__, in one context, is returned by __context_resume__ (or
+__context_start__, depending upon which function was called previously) in the
+other context.
+__context_start__ has no argument because it enters the start of the function,
+and there is no previous call to __context_suspend__ to return a value.
+
+ boost::contexts::context ctx;
+
+ void fn()
+ {
+ int i = 7;
+ std::cout << "fn(): local variable i == " << i << std::endl;
+
+ // save current context
+ // transfer execution control back to caller
+ // pass content of variable back
+ int j = ctx.suspend( i);
+ // j == 10 because x == 10 in main()
+
+ std::cout << "transfered value: " << j << std::endl;
+ }
+
+ int main( int argc, char * argv[])
+ {
+ ctx = boost::contexts::context( fn,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind,
+ boost::contexts::return_to_caller);
+
+ std::cout << "main() calls context ctx" << std::endl;
+
+ // start the context ctx for the first time
+ // enter fn()
+ int x = ctx.start();
+ // x == 7 because i == 7 in fn()
+
+ std::cout << "transfered value: " << x << std::endl;
+
+ x = 10;
+ // ctx.suspend() was called so we returned from start()
+ ctx.resume( x);
+
+ std::cout << "Done" << std::endl;
+
+ return EXIT_SUCCESS;
+ }
+
+ output:
+ main() calls context ctx
+ fn(): local variable i == 7
+ transfered value: 7
+ transfered value: 10
+ Done
+
+
+[heading Exceptions in __context_fn__]
+
+If the __context_fn__ emits an exception, std::terminate() is called.
+
+[important Code executed by context must not prevent the propagation of the
+__forced_unwind__ exception. Absorbing that exception will cause stack
+unwinding to fail. Thus, any code that catches all exceptions must rethrow the
+pending exception.]
+
+ try
+ {
+ // code that might throw
+ }
+ catch( forced_unwind)
+ {
+ throw;
+ }
+ catch(...)
+ {
+ // possibly not rethrow pending exception
+ }
+
+
+[heading Handling execution context termination]
+
+The last context constructor argument is an enumerated type which determines
+what should happen when the context is complete (that is, when the
+__context_fn__ returns). The available values are `return_to_caller` and
+`exit_application`.
+
+When the last constructor argument is `return_to_caller`, execution control is
+transferred back to the last invocation of __context_start__ or
+__context_resume__ when the context is complete, as shown in this example:
+
+ boost::contexts::context ctx;
+
+ void fn( int j)
+ {
+ for( int i = 0; i < j; ++i)
+ {
+ std::cout << "fn(): local variable i == " << i << std::endl;
+ ctx.suspend();
+ }
+
+ // fn() returns
+ // execution control is transfered back to main()
+ }
+
+ int main( int argc, char * argv[])
+ {
+ ctx = boost::contexts::context( fn, 7,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind,
+ boost::contexts::return_to_caller);
+
+ ctx.start();
+ while ( ! ctx.is_complete() )
+ {
+ std::cout << "main() calls context ctx" << std::endl;
+ ctx.resume();
+ }
+
+ // fn() returned; the context is complete
+
+ std::cout << "Done" << std::endl;
+
+ return EXIT_SUCCESS;
+ }
+
+ output:
+ fn(): local variable i == 0
+ main() calls context ctx
+ fn(): local variable i == 1
+ main() calls context ctx
+ fn(): local variable i == 2
+ main() calls context ctx
+ fn(): local variable i == 3
+ main() calls context ctx
+ fn(): local variable i == 4
+ main() calls context ctx
+ fn(): local variable i == 5
+ main() calls context ctx
+ fn(): local variable i == 6
+ main() calls context ctx
+ Done
+
+When the last constructor argument is `exit_application`, the application
+terminates with an exit status of zero when the context is complete, as shown in
+the following example:
+
+ boost::contexts::context ctx;
+
+ void fn( int j)
+ {
+ for( int i = 0; i < j; ++i)
+ {
+ std::cout << "fn(): local variable i == " << i << std::endl;
+ ctx.suspend();
+ }
+
+ // fn() returns
+ // application will terminate
+ }
+
+ int main( int argc, char * argv[])
+ {
+ ctx = boost::contexts::context( fn, 7,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind,
+ boost::contexts::exit_application);
+
+ ctx.start();
+ while ( ! ctx.is_complete() )
+ {
+ std::cout << "main() calls context ctx" << std::endl;
+ ctx.resume();
+ }
+
+ // never reached
+ return EXIT_SUCCESS;
+ }
+
+ output:
+ fn() calls context ctx
+ fn(): local variable i == 1
+ main() calls context ctx
+ fn(): local variable i == 2
+ main() calls context ctx
+ fn(): local variable i == 3
+ main() calls context ctx
+ fn(): local variable i == 4
+ main() calls context ctx
+ fn(): local variable i == 5
+ main() calls context ctx
+ fn(): local variable i == 6
+ main() calls context ctx
+
+
+[heading Chaining contexts]
+
+__boost_context__ provides the ability to chain context instances by passing
+a reference to another context, other than that __not_a_context__, as the
+last constructor argument.
+In this way, it is possible to create a chain of contexts. Depending on the
+`do_return` argument in the constructor of the last context in the chain, the
+application terminates or execution control is transferred back to the last
+invocation of __context_resume__. Each call of __context_suspend__, for the
+chained context instances, will return to __context_resume__.
+
+ boost::contexts::context ctx2;
+
+ void fn1()
+ {
+ std::cout << "fn1(): when this function returns fn2() will be entered" << std::endl;
+ }
+
+ void fn2()
+ {
+ std::cout << "fn2(): first time entered" << std::endl;
+ ctx2.suspend();
+ std::cout << "fn2(): second time entered\n";
+ std::cout << "fn2(): return to main()" << std::endl;
+ }
+
+ int main( int argc, char * argv[])
+ {
+ {
+ // ctx2 will return to ctx2.resume()
+ ctx2 = boost::contexts::context(
+ fn2,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind,
+ boost::contexts::return_to_caller);
+
+ // ctx1 defines ctx2 as its successor
+ boost::contexts::context ctx1(
+ fn1,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind,
+ ctx2);
+
+ // transfer execution control to ctx1
+ // fn1() is entered
+ ctx1.start();
+
+ // ctx2.suspend() was called
+ }
+
+ // ctx2 was already started by ctx1
+ ctx2.resume();
+
+ std::cout << "Done" << std::endl;
+
+ return EXIT_SUCCESS;
+ }
+
+ output:
+ fn1(): when this function returns fn2() will be entered
+ fn2(): first time entered
+ fn2(): second time entered
+ fnd2(): return to main()
+ Done
+
+[important Call __context_start__ only on the first context in a chain.]
+
+
+[heading Stack unwinding]
+
+Sometimes it is necessary to unwind the stack of an unfinished context to
+destroy local stack variables so they can release allocated resources (RAII
+pattern). The next to last argument of the context constructor, `do_unwind`,
+indicates whether the destructor should unwind the stack.
+Stack unwinding can also be triggered by calling __context_unwind__.
+
+Stack unwinding assumes the following preconditions:
+
+* The context is not __not_a_context__
+* The context is not complete
+* The context is not running
+* The context owns a stack
+
+After unwinding, a __context__ is complete.
+
+
+ boost::contexts::context ctx;
+
+ struct X
+ {
+ X()
+ { std::cout << "X()" << std::endl; }
+
+ ~X()
+ { std::cout << "~X()" << std::endl; }
+ };
+
+ void fn()
+ {
+ X x;
+
+ for( int i = 0;; ++i)
+ {
+ std::cout << "fn(): " << i << std::endl;
+ // transfer execution control back to main()
+ ctx.suspend();
+ }
+ }
+
+ int main( int argc, char * argv[])
+ {
+ ctx = boost::contexts::context(
+ fn,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind,
+ boost::contexts::return_to_caller);
+ ctx.start();
+ for ( int i = 0; i < 5; ++i)
+ {
+ // transfer execution control to fn()
+ ctx.resume();
+ }
+
+ std::cout << "ctx is complete: " << std::boolalpha << ctx.is_complete() << "\n";
+ std::cout << "call ctx.unwind_stack()" << std::endl;
+
+ // unwind the stack
+ // X::~X() will be called
+ ctx.unwind_stack(); // unwind the stack
+
+ std::cout << "ctx is complete: " << std::boolalpha << ctx.is_complete() << "\n";
+ std::cout << "Done" << std::endl;
+
+ return EXIT_SUCCESS;
+ }
+
+ output:
+ X()
+ fn(): 0
+ fn(): 1
+ fn(): 2
+ fn(): 3
+ fn(): 4
+ fn(): 5
+ ctx is complete: false
+ call ctx.unwind_stack()
+ ~X()
+ ctx is complete: true
+ Done
+
+[important You must not swallow __forced_unwind__ exceptions!]
+
+
+[section:context Class `context`]
+
+ #include <boost/context/context.hpp>
+
+ class context
+ {
+ public:
+ context();
+
+ template< typename Fn >
+ context( Fn fn, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return);
+
+ template< typename Fn, typename Allocator >
+ context( Fn fn, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return, Allocator const& alloc);
+
+ template< typename Fn >
+ context( Fn fn, std::size_t size, flag_unwind_t do_unwind, context & nxt);
+
+ template< typename Fn, typename Allocator >
+ context( Fn fn, std::size_t size, flag_unwind_t do_unwind, context & nxt, Allocator const& alloc);
+
+ template< typename Fn, typename A0 >
+ context( Fn fn A0 a0, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return);
+ ...
+ template< typename Fn, typename A0,..., typename A9 >
+ context( Fn fn A0 a0,..., A9, a9, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return);
+
+ template< typename Fn, typename Allocator, typename A0 >
+ context( Fn fn A0 a0, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return, Allocator const& alloc);
+ ...
+ template< typename Fn, typename Allocator, typename A0,..., typename A9 >
+ context( Fn fn A0 a0,..., A9, a9, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return, Allocator const& alloc);
+
+ template< typename Fn, typename A0 >
+ context( Fn fn A0 a0, std::size_t size, flag_unwind_t do_unwind, context & nxt);
+ ...
+ template< typename Fn, typename A0,..., typename A9 >
+ context( Fn fn A0 a0,..., A9, a9, std::size_t size, flag_unwind_t do_unwind, context & nxt);
+
+ template< typename Fn, typename Allocator, typename A0 >
+ context( Fn fn A0 a0, std::size_t size, flag_unwind_t do_unwind, context & nxt, Allocator const& alloc);
+ ...
+ template< typename Fn, typename Allocator, typename A0,..., typename A9 >
+ context( Fn fn A0 a0,..., A9, a9, std::size_t size, flag_unwind_t do_unwind, context & nxt, Allocator const& alloc);
+
+ template< typename Fn >
+ context( Fn && fn, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return);
+
+ template< typename Fn, typename Allocator >
+ context( Fn && fn, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return, Allocator const& alloc);
+
+ template< typename Fn >
+ context( Fn && fn, std::size_t size, flag_unwind_t do_unwind, context & nxt);
+
+ template< typename Fn, typename Allocator >
+ context( Fn && fn, std::size_t size, flag_unwind_t do_unwind, context & nxt, Allocator const& alloc);
+
+ ~context();
+
+ context( context && other);
+
+ context & operator=( context && other);
+
+ operator unspecified-bool-type() const;
+
+ bool operator!() const;
+
+ void swap( context & other);
+
+ bool is_complete() const;
+
+ bool is_running() const;
+
+ intptr_t start();
+
+ intptr_t resume( intptr_t vp = 0);
+
+ intptr_t suspend( intptr_t vp = 0);
+
+ void unwind_stack();
+ };
+
+ void swap( context & l, context & r);
+
+[heading `context()`]
+[variablelist
+[[Effects:] [Creates a context representing a __not_a_context__.]]
+[[Throws:] [Nothing.]]
+]
+
+[heading `template< typename Fn > context( Fn fn, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return)`]
+[variablelist
+[[Preconditions:] [`size` > minimum_stacksize(), `size` < maximum_stacksize() when ! is_stack_unbound().]]
+[[Effects:] [Creates a context which will execute `fn`. If `do_unwind` is `stack_unwind` the destructor of `*this` unwinds
+the stack before destructing it. If `do_return` is `exit_application` the application exits with return code `0`, otherwise
+execution control is transfered back to the invoker (`resume()` returns).]]
+[[Throws:] [__invalid_argument__ if a precondition is not satisfied.]]
+]
+
+[heading `template< typename Fn, typename Allocator > context( Fn fn, std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return, Allocator const& alloc)`]
+[variablelist
+[[Effects:] [Creates a context which will execute `fn`. If `do_unwind` is `stack_unwind` the destructor of `*this` unwinds
+the stack before destructing it. If `do_return` is `exit_application` the application exits with return code `0`, otherwise
+execution control is transfered back to the invoker (`resume()` returns).]]
+[[Throws:] [depends on `alloc` if a precondition is not satisfied.]]
+]
+
+[heading `template< typename Fn > context( Fn fn, std::size_t size, flag_unwind_t do_unwind, context & nxt)`]
+[variablelist
+[[Preconditions:] [`size` > minimum_stacksize(), `size` < maximum_stacksize() when ! is_stack_unbound(), `nxt` is not a __not_a_context__.]]
+[[Effects:] [Creates a context which will execute `fn`. If `do_unwind` is `stack_unwind` the destructor of `*this` unwinds
+the stack before destructing it. execution control is transfered to `nxt` if `fn` returns (`nxt` is linked).]]
+[[Throws:] [__invalid_argument__ if a precondition is not satisfied.]]
+]
+
+[heading `template< typename Fn, typename Allocator > context( Fn fn, std::size_t size, flag_unwind_t do_unwind, context & nxt, Allocatorconst& alloc)`]
+[variablelist
+[[Preconditions:] [`nxt` is not a __not_a_context__.]]
+[[Effects:] [Creates a context which will execute `fn`. If `do_unwind` is `stack_unwind` the destructor of `*this` unwinds
+the stack before destructing it. execution control is transfered to `nxt` if `fn` returns (`nxt` is linked).]]
+[[Throws:] [depends on `alloc` if a precondition is not satisfied.]]
+]
+
+[heading `template< typename Fn, typename A0,... > context( Fn fn, A0 a0,..., std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return)`]
+[variablelist
+[[Preconditions:] [`size` > minimum_stacksize(), `size` < maximum_stacksize() when ! is_stack_unbound().]]
+[[Effects:] [Creates a context which will execute `fn` (arguments `A0`,... are bound to `fn`). If `do_unwind` is `stack_unwind` the destructor of `*this` unwinds
+the stack before destructing it. If `do_return` is `exit_application` the application exits with return code `0`, otherwise
+execution control is transfered back to the invoker (`resume()` returns).]]
+[[Throws:] [__invalid_argument__ if a precondition is not satisfied.]]
+]
+
+[heading `template< typename Fn, typename Allocator, typename A0,... > context( Fn fn, A0 a0,..., std::size_t size, flag_unwind_t do_unwind, flag_return_t do_return, Allocator const& alloc)`]
+[variablelist
+[[Preconditions:] [`size` > minimum_stacksize(), `size` < maximum_stacksize() when ! is_stack_unbound().]]
+[[Effects:] [Creates a context which will execute `fn` (arguments `A0`,... are bound to `fn`). If `do_unwind` is `stack_unwind` the destructor of `*this` unwinds
+the stack before destructing it. If `do_return` is `exit_application` the application exits with return code `0`, otherwise
+execution control is transfered back to the invoker (`resume()` returns).]]
+[[Throws:] [depends on `alloc` if a precondition is not satisfied.]]
+]
+
+[heading `template< typename Fn, typename A0,... > context( Fn fn, A0 a0,..., std::size_t size, flag_unwind_t do_unwind, context & nxt)`]
+[variablelist
+[[Preconditions:] [`size` > minimum_stacksize(), `size` < maximum_stacksize() when ! is_stack_unbound(), `nxt` is not a __not_a_context__.]]
+[[Effects:] [Creates a context which will execute `fn` (arguments`A0`,... are bound to `fn`). If `do_unwind` is `stack_unwind` the destructor of `*this` unwinds
+the stack before destructing it. execution control is transfered to `nxt` if `fn` returns (`nxt` is linked).]]
+[[Throws:] [__invalid_argument__ if a precondition is not satisfied.]]
+]
+
+[heading `template< typename Fn, typename Allocator, typename A0,... > context( Fn fn, A0 a0,..., std::size_t size, flag_unwind_t do_unwind, context & nxt, Allocator const& alloc)`]
+[variablelist
+[[Preconditions:] [`nxt` is not a __not_a_context__.]]
+[[Effects:] [Creates a context which will execute `fn` (arguments`A0`,... are bound to `fn`). If `do_unwind` is `stack_unwind` the destructor of `*this` unwinds
+the stack before destructing it. execution control is transfered to `nxt` if `fn` returns (`nxt` is linked).]]
+[[Throws:] [depends on `alloc` if a precondition is not satisfied.]]
+]
+
+[heading `~context()`]
+[variablelist
+[[Effects:] [Destroys the instance and deallocates the stack. Unwinds the stack if it was specified in the
+constructor of `*this`.]]
+[[Throws:] [Nothing.]]
+]
+
+[heading `context( context && other)`]
+[variablelist
+[[Effects:] [Moves the internal data of `other` to `*this`.
+`other` becomes __not_a_context__.]]
+[[Throws:] [Nothing.]]
+]
+
+[heading `context & operator=( context && other)`]
+[variablelist
+[[Effects:] [Destroys the internal data of `*this` and moves the
+internal data of `other` to `*this`. `other` becomes __not_a_context__.]]
+[[Throws:] [Nothing.]]
+]
+
+[heading `operator unspecified-bool-type() const`]
+[variablelist
+[[Returns:] [If `*this` refers to __not_a_context__, the function returns
+false. Otherwise true.]]
+[[Throws:] [Nothing.]]
+]
+
+[heading `bool operator!() const`]
+[variablelist
+[[Returns:] [If `*this` refers not to __not_a_context__, the function returns
+true. Otherwise false.]]
+[[Throws:] [Nothing.]]
+]
+
+[heading `void swap( context & other)`]
+[variablelist
+[[Effects:] [Swaps the internal data from `*this` with the values
+of `other`.]]
+[[Throws:] [Nothing.]]
+]
+
+[heading `bool is_complete() const`]
+[variablelist
+[[Preconditions:] [`*this` is not a __not_a_context__.]]
+[[Effects:] [Returns `true` if context-function of `*this` has returned.]]
+[[Throws:] [Nothing.]]
+]
+
+[heading `bool is_running() const`]
+[variablelist
+[[Preconditions:] [`*this` is not a __not_a_context__.]]
+[[Effects:] [Returns `true` if `*this` is the currently active context.]]
+[[Throws:] [Nothing.]]
+]
+
+[heading `intptr_t start()`]
+[variablelist
+[[Preconditions:] [`*this` is not a __not_a_context__, `! is_complete()` and
+`! is_running()`.]]
+[[Effects:] [`start()` enters the __context_fn__ `fn` with which the context was
+constructed. Upon return, the context was either left via
+`suspend()` or the __context_fn__ returned.]]
+[[Returns:] [A intptr_t passed to `suspend()` is returned if the context
+was left with `suspend()`.]]
+[[Throws:] [Nothing.]]
+]
+
+[heading `intptr_t resume( intptr_t vp = 0)`]
+[variablelist
+[[Preconditions:] [`*this` is not a __not_a_context__, `! is_complete()` and
+`! is_running()`, `start()` was called before.]]
+[[Effects:] [None, if *this was not suspended by a previous call to suspend().
+Otherwise, execution control is transferred back to the caller of suspend(), thereby
+resuming *this. The argument, vp, will be returned by the previous call to suspend().]]
+[[Throws:] [Nothing.]]
+]
+
+[heading `intptr_t suspend( intptr_t vp = 0)`]
+[variablelist
+[[Preconditions:] [`*this` is not a __not_a_context__, `! is_complete()` and
+`is_running()`.]]
+[[Effects:] [Transfers execution control to the caller of the most recent call to
+start() or resume(). The argument, vp, will be returned by start() or resume().]]
+[[Throws:] [__forced_unwind__ if __context_unwind__ was called.]]
+]
+
+[heading `void unwind_stack()`]
+[variablelist
+[[Preconditions:] [`*this` is not a __not_a_context__, `! is_complete()` and
+`! is_running()`.]]
+[[Effects:] [Destroys all objects allocated on the stack, owned by *this, in the
+reverse order of their allocation.]]
+[[Throws:] [Nothing.]]
+[[Postconditions:] [`*this` is not a __not_a_context__ and `is_complete()`.]]
+]
+
+[heading Non-member function `swap()`]
+
+ void swap( context & l, context & r);
+
+[variablelist
+[[Effects:] [As if 'l.swap( r)'.]]
+]
+
+[endsect]
+
+[endsect]

Added: trunk/libs/context/doc/continuation.qbk
==============================================================================
--- (empty file)
+++ trunk/libs/context/doc/continuation.qbk 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,103 @@
+[/
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt
+]
+
+[section:continuation Continuation]
+
+Adapted from [@https://code.google.com/p/jyield/wiki/Samples the Java
+continuation] documentation example.
+
+Class `continuation` provides the ability for a functor to suspend itself.
+The functor is required to accept a const reference to its own `continuation`
+instance.
+
+ class continuation
+ {
+ private:
+ boost::contexts::context ctx_;
+ boost::function< void( continuation &) > fn_;
+ bool started_;
+
+ void trampoline_()
+ { fn_( * this); }
+
+ public:
+ continuation( boost::function< void( continuation &) > const& fn) :
+ ctx_(
+ & continuation::trampoline_, this,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind,
+ boost::contexts::return_to_caller),
+ false),
+ fn_( fn), started_( false)
+ {}
+
+ void resume()
+ {
+ if ( ! started_)
+ {
+ started_ = true;
+ ctx_.start();
+ }
+ else ctx_.resume();
+ }
+
+ void suspend()
+ { ctx_.suspend(); }
+
+ bool is_complete() const
+ { return ctx_.is_complete(); }
+ };
+
+
+The functions `first()` and `second()` are so-called coroutines running 'quasi
+parallel'.
+Please note that the variables in the for-loops have local scope.
+
+ void first( continuation & c)
+ {
+ std::cout << "started first! ";
+ for ( int i = 0; i < 10; ++i)
+ {
+ c.suspend(); // jump back to main()
+ std::cout << "a" << i; // output
+ }
+ }
+
+ void second( continuation & c)
+ {
+ std::cout << "started second! ";
+ for ( int i = 0; i < 10; ++i)
+ {
+ c.suspend(); // jump back to main()
+ std::cout << "b" << i; // output
+ }
+ }
+
+ int main( int argc, char * argv[])
+ {
+ {
+ continuation c1( boost::bind( first, _1) );
+ continuation c2( boost::bind( second, _1) );
+ // loop until coroutines c1 and c2 are complete
+ while ( ! c1.is_complete() && ! c2.is_complete() ) {
+ c1.resume(); // call coroutine c1 -> first()
+ std::cout << " ";
+ c2.resume(); // call coroutine c2 -> second()
+ std::cout << " ";
+ }
+ }
+
+ std::cout << "\nDone" << std::endl;
+
+ return EXIT_SUCCESS;
+ }
+
+ output:
+ started first! started second! a0 b0 a1 b1 a2 b2 a3 b3 a4 b4 a5 b5 a6 b6 a7 b7 a8 b8 a9 b9
+ Done
+
+[endsect]

Added: trunk/libs/context/doc/enumerator.qbk
==============================================================================
--- (empty file)
+++ trunk/libs/context/doc/enumerator.qbk 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,166 @@
+[/
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt
+]
+
+[section:enumerator Enumerator]
+
+Class `power` computes the power of `number` for the exponents in the range
+from `1` to `number` (constructor arguments).
+
+
+ class power
+ {
+ public:
+ power( int number, int exponent);
+
+ bool get( int & data);
+ };
+
+
+Each call to `power::get()` returns a boolean indicating a vaild result.
+The reference argument `data` contains the computed result.
+
+
+ int main()
+ {
+ {
+ power pw( 2, 8);
+ int i;
+ // pw.get() returns the computed result
+ // for each value from 1 to 8
+ // return value of pw.get() indicates that
+ // a valid result
+ while ( pw.get( i) ) {
+ std::cout << i << " ";
+ }
+ }
+
+ std::cout << "\nDone" << std::endl;
+
+ return EXIT_SUCCESS;
+ }
+
+ output:
+ 2 4 8 16 32 64 128 256
+ Done
+
+
+In `main()` an instance of `power` is constructed, computing the power of 2
+for exponents in the range from 1 to 8 by each call to `power::get()`.
+
+It is intended to compute the numbers in a loop and transfer each result to the
+caller without disrupting the loop.
+
+__boost_context__ can be used to implement an equivalent to C#'s `yield`
+facility (C# provides the keywords `yield return` and `yield break`).
+For this purpose helper-template `enumerator` is defined containing the private
+member `ctx_` executing `enumerate()` as __context_fn__.
+
+ template< typename T >
+ class enumerator {
+ private:
+ boost::contexts::context ctx_;
+ bool complete_;
+ bool do_unwind_;
+ bool started_;
+
+ static void run( enumerator * self)
+ { self->enumerate(); }
+
+ protected:
+ virtual void enumerate() = 0;
+
+ void yield_return( T const& v)
+ {
+ intptr_t vp = reinterpret_cast< intptr_t >( & v);
+ ctx_.suspend( vp);
+ }
+
+ void yield_break()
+ {
+ complete_ = true;
+ ctx_.suspend();
+ }
+
+ public:
+ enumerator( bool do_unwind = true):
+ ctx_(
+ & enumerator::run, this,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind,
+ boost::contexts::return_to_caller),
+ complete_( false),
+ do_unwind_( do_unwind),
+ started_( false)
+ {}
+
+ ~enumerator()
+ {
+ if ( do_unwind_ && ! ctx_.is_complete() )
+ ctx_.unwind_stack();
+ }
+
+ bool get( T & result)
+ {
+ intptr_t vp = 0;
+ if ( ! started_)
+ {
+ started_ = true;
+ vp = ctx_.start();
+ }
+ else
+ {
+ vp = ctx_.resume();
+ }
+ if ( vp) result = * reinterpret_cast< T * >( vp);
+ return ! ( complete_ || ctx_.is_complete() );
+ }
+ };
+
+
+Member-function `get()` starts / resumes `context `ctx_` by calling
+__context_start__ / __context_resume__ so that `enumerate()` is (re-)entered.
+Functions __context_start__ / __context_resume__ return the computed values.
+
+`yield_return()` (equivalent to C# `yield return`) jumps to `get()` transfering
+the execution control and computed value back.
+With `yield_break()` (equivalent to C# `yield break`) the control is
+unconditionally returned to `get()` to signal the end of iteration.
+
+Class `power` derives from `enumerate< int >` and its implementation of
+`enumerate()` computes the power in a local loop.
+Each computed result is transfered to `get()` by calling `yield_return()`.
+
+
+ class power : public enumerator< int >
+ {
+ private:
+ void enumerate()
+ {
+ int counter = 0;
+ int result = 1;
+ // local scoped while loop
+ while ( counter++ < exponent_)
+ {
+ // compute the value
+ result = result * number_;
+
+ // return the value by jumping to calling context
+ // == jump to while-loop in main()
+ yield_return( result);
+ }
+ }
+
+ int number_;
+ int exponent_;
+
+ public:
+ power( int number, int exponent) :
+ number_( number), exponent_( exponent)
+ {}
+ };
+
+[endsect]

Added: trunk/libs/context/doc/examples.qbk
==============================================================================
--- (empty file)
+++ trunk/libs/context/doc/examples.qbk 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,14 @@
+[/
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt
+]
+
+[section:examples Examples]
+
+[include enumerator.qbk]
+[include continuation.qbk]
+[include asio.qbk]
+
+[endsect]

Added: trunk/libs/context/doc/fcontext.qbk
==============================================================================
--- (empty file)
+++ trunk/libs/context/doc/fcontext.qbk 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,174 @@
+[/
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt
+]
+
+[section:capi Low level API (boost_fcontext_t)]
+
+__boost_context__ uses and provides a low level API which implements the
+execution control transfer mechanism. The boost_fcontext_t API provides a
+similar interface like [@http://www.kernel.org/doc/man-pages/online/pages/man2/getcontext.2.html ucontext_t].
+boost_fcontext_t and its functions are located in the global namespace and the
+functions are declared as extern "C".
+
+ #include <cstdio>
+ #include <cstdlib>
+ #include <cstring>
+ #include <vector>
+
+ #include <boost/cstdint.hpp>
+ #include <boost/context/fcontext.hpp>
+
+ boost_fcontext_t fcm, fc1, fc2;
+
+ void f1( intptr_t p)
+ {
+ (void) p;
+ fprintf(stderr,"f1() started\n");
+ fprintf(stderr,"f1: call boost_fcontext_jump( & fc1, & fc2, 0)\n");
+ // jump to context fc2
+ boost_fcontext_jump( & fc1, & fc2, 0);
+ // returned from context fc2 (function f2())
+ // return from function f1()
+ fprintf(stderr,"f1() returns\n");
+ }
+
+ void f2( intptr_t p)
+ {
+ (void) p;
+ fprintf(stderr,"f2() started\n");
+ fprintf(stderr,"f2: call boost_fcontext_jump( & fc2, & fc1, 0)\n");
+ // jump to context fc1
+ boost_fcontext_jump( & fc2, & fc1, 0);
+ // never reached
+ fprintf(stderr,"f2() returns\n");
+ }
+
+ int main( int argc, char * argv[])
+ {
+ // creat two protected stacks
+ boost::contexts::protected_stack b1(262144);
+ boost::contexts::protected_stack b2(262144);
+
+ // let context fc1 use stack b1
+ fc1.fc_stack.ss_base = b1.address();
+ fc1.fc_stack.ss_limit =
+ static_cast< char * >( fc1.fc_stack.ss_base) - b1.size();
+ // link context fcm;
+ // fcm will be invoked after fc1 terminated
+ fc1.fc_link = & fcm;
+ // context fc1 used f1() as context function
+ boost_fcontext_make( & fc1, f1, 0);
+
+ // let context fc2 use stack b2
+ fc2.fc_stack.ss_base = b2.address();
+ fc2.fc_stack.ss_limit =
+ static_cast< char * >( fc2.fc_stack.ss_base) - b2.size();
+ // context fc2 used f2() as context function
+ boost_fcontext_make( & fc2, f2, 0);
+
+ // start context f1; entering f1()
+ fprintf(stderr,"main: call boost_fcontext_start( & fcm, & fc1)\n");
+ boost_fcontext_start( & fcm, & fc1);
+
+ fprintf( stderr, "main() returns\n");
+ return EXIT_SUCCESS;
+ }
+
+ output:
+ main: call boost_fcontext_start( & fcm, & fc1)
+ f1() started
+ f1: call boost_fcontext_jump( & fc1, & fc2, 0)
+ f2() started
+ f2: call boost_fcontext_jump( & fc2, & fc1, 0)
+ f1() returns
+ main() returns
+
+Function `boost_fcontext_start()` enters the __context_fn__ `f1()` by starting
+context fc1 (context fcm saves the registers of `main()`). For jumping between
+context's fc1 and fc2 `boost_fcontext_jump()` is called.
+Because context fcm is chained to fc1, `main()` is entered (returning from
+`boost_fcontext_start()`) after context fc1 becomes complete (return from
+`f1()`).
+
+[important The low level API is the part to port to new platforms.]
+
+
+[section:boost_fcontext Struct `boost_fcontext_t` and related functions]
+
+ typedef struct boost_fcontext_stack boost_fcontext_stack_t;
+ struct boost_fcontext_stack
+ {
+ void * ss_base;
+ void * ss_limit;
+ };
+
+ typedef struct boost_fcontext boost_fcontext_t;
+ struct boost_fcontext
+ {
+ < platform specific >
+
+ boost_fcontext_stack_t fc_stack;
+ boost_fcontext_t * fc_link;
+ };
+
+ intptr_t boost_fcontext_start( boost_fcontext_t * ofc, boost_fcontext_t const* nfc);
+ intptr_t boost_fcontext_jump( boost_fcontext_t * ofc, boost_fcontext_t const* nfc, intptr_t vp);
+ void boost_fcontext_make( boost_fcontext_t * fc, void(* fn)(void*), intptr_t p);
+
+[heading `ss_base`]
+[variablelist
+[[Member:] [Pointer to the top of the stack.]]
+]
+
+[heading `ss_limit`]
+[variablelist
+[[Member:] [Pointer to the bottom of the stack.]]
+]
+
+[heading `fc_stack`]
+[variablelist
+[[Member:] [Tracks the memory for the context's stack.]]
+]
+
+[heading `fc_link`]
+[variablelist
+[[Member:] [The address of the next context link in a chain, if any.]]
+]
+
+[heading `intptr_t boost_fcontext_start( boost_fcontext_t * ofc,
+ boost_fcontext_t * nfc)`]
+[variablelist
+[[Effects:] [Stores the current context data (stack pointer, instruction
+pointer, and CPU registers) to `*ofc` and restores the context data from `*nfc`,
+which implies jumping to `*nfc`'s execution context. This function must be
+called when first entering `*nfc`'s execution context.]]
+[[Returns:] [The result of calling `boost_fcontext_jump()`.]]
+]
+
+[heading `intptr_t boost_fcontext_jump( boost_fcontext_t * ofc, boost_fcontext_t * nfc, intptr_t p)`]
+[variablelist
+[[Effects:] [Stores the current context data (stack pointer, instruction
+pointer, and CPU registers) to `*ofc` and restores the context data from `*nfc`,
+which implies jumping to `*nfc`'s execution context. The intptr_t argument, `p`,
+is passed to the current context to be returned by the most recent call to
+`boost_fcontext_start()` or `boost_fcontext_jump()` in the same thread.]]
+[[Returns:] [The third pointer argument passed to the most recent call to
+`boost_fcontext_jump()`, if any.]]
+]
+
+[heading `void boost_fcontext_make( boost_fcontext_t * fc, void(*fn)(intptr_t), intptr_t p)`]
+[variablelist
+[[Precondition:] [A stack is applied to `*fc` before
+`boost_fcontext_make()` is called. If a successor context should be executed
+after `*fc` finishes the address of the successor context must be stored ir
+`fc->fc_link`. The application exits otherwise.]]
+[[Effects:] [Modifies `*fc` in order to execute `fn` with argument `p` when the
+context is activated next.]]
+]
+
+[endsect]
+
+[endsect]

Added: trunk/libs/context/doc/overview.qbk
==============================================================================
--- (empty file)
+++ trunk/libs/context/doc/overview.qbk 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,45 @@
+[/
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt
+]
+
+[section:overview Overview]
+
+__boost_context__ is a foundational library that provides a sort of cooperative
+multitasking on a single thread. By providing an abstraction of the current
+execution state in the current thread, including the stack (with local
+variables) and stack pointer, all registers and CPU flags, and the instruction
+pointer, a __context__ instance represents a specific point in the application's
+execution path. This is useful for building higher-level abstractions, like
+__coroutines__, __coop_threads__ or an aquivalent to
+[@http://msdn.microsoft.com/en-us/library/9k7k7cf0%28v=vs.80%29.aspx C# keyword __yield__]
+in C++ ([cs_example_link see enumerator example]).
+
+A __context__ provides the means to suspend the current execution path and to
+transfer execution control, thereby permitting another __context__ to run on the
+current thread. This stateful transfer mechanism enables a __context__ to
+suspend execution from within nested functions and, later, to resume from where
+it was suspended. While the execution path represented by a __context__ only
+runs on a single thread, it can be migrated to another thread at any given time.
+
+A context switch between threads requires system calls (involving the OS
+kernel), which can cost thousands of CPU cycles on x86 CPUs. By contrast,
+transferring control among them requires only a few hundred CPU cycles because
+it does not involve system calls as it is done within a single thread.
+
+In order to use the classes and functions described here, you can either include
+the specific headers specified by the descriptions of each class or function, or
+include the master library header:
+
+ #include <boost/context/all.hpp>
+
+which includes all the other headers in turn.
+
+All functions and classes are contained in the namespace __context_ns__.
+
+__boost_context__ depends on __boost_move__.
+
+
+[endsect]

Added: trunk/libs/context/doc/pdf/arm-aapcs.pdf
==============================================================================
Binary file. No diff available.

Added: trunk/libs/context/doc/pdf/arm-linux-aapcs.pdf
==============================================================================
Binary file. No diff available.

Added: trunk/libs/context/doc/pdf/iso_c99.pdf
==============================================================================
Binary file. No diff available.

Added: trunk/libs/context/doc/pdf/mips-o32.pdf
==============================================================================
Binary file. No diff available.

Added: trunk/libs/context/doc/pdf/ppc32-sysv.pdf
==============================================================================
Binary file. No diff available.

Added: trunk/libs/context/doc/pdf/ppc64-sysv.pdf
==============================================================================
Binary file. No diff available.

Added: trunk/libs/context/doc/pdf/x86_32-sysv.pdf
==============================================================================
Binary file. No diff available.

Added: trunk/libs/context/doc/pdf/x86_64-sysv.pdf
==============================================================================
Binary file. No diff available.

Added: trunk/libs/context/doc/performance.qbk
==============================================================================
--- (empty file)
+++ trunk/libs/context/doc/performance.qbk 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,35 @@
+[/
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt
+]
+
+[section:performance Performance]
+
+Performance of __boost_context__ was measured on the platforms shown in the
+following table. Performance measurements were taken using `rdtsc`, with
+overhead corrections, on x86 platforms. In each case, stack protection was
+active, cache warm-up was accounted for, and the one running thread was pinned
+to a single CPU. The code was compiled using the build options,
+'variant=release cxxflags=-DBOOST_DISABLE_ASSERTS'.
+
+The numbers in the table are the number of cycles per iteration, based upon an
+average computed over 1000 iterations.
+
+[table Perfomance of context switch
+ [[Platform] [ucontext_t] [fcontext_t]]
+ [
+ [AMD Athlon 64 DualCore 4400+ (32bit Linux)]
+ [1771 cycles]
+ [146 cycles]
+ ]
+ [
+ [Intel Core2 Quad (64bit Linux)]
+ [1739 cycles]
+ [117 cycles]
+ ]
+]
+
+
+[endsect]

Added: trunk/libs/context/doc/rationale.qbk
==============================================================================
--- (empty file)
+++ trunk/libs/context/doc/rationale.qbk 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,118 @@
+[/
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt
+]
+
+[section:rationale Rationale]
+
+[heading NoThrow guarantee]
+
+Member functions of __context__ do not thow exceptions but do require that
+certain preconditions are satisifed:
+context jumps can only be made by instances which are not a __not_a_context__
+and which are not complete.
+
+
+[heading Pimpl idiom]
+
+In order to support move semantics and context switching operations, the use of
+the Pimpl Idiom was necessary.
+A nice feature is that a __context__ has the size of a pointer, so it fits into
+a register.
+
+With the current design the constructor accepts functors and its arguments
+similiar to __thread__.
+
+The Pimpl Idiom allows type-erasing the __stack_allocator__ type.
+
+
+[heading Unwinding]
+
+In order to release resources allocated on the stack, unwinding the stack must be
+supported.
+The current implementation throws a exception in order to unwind the stack (jump
+back to invocation of `suspend()`). The special exception is caught inside the
+trampoline function (first function on top of stack).
+
+
+[heading Protecting the stack]
+
+Because the stack's size is fixed -- there is no support for split stacks -- it
+is important to protect against exceeding the stack's bounds. Otherwise, in the
+best case, overrunning the stack's memory will result in a segmentation fault or
+access violation and, in the worst case, the application's memory will be
+overwritten. `stack_allocator` appends a guard page to the stack to help detect
+overruns. The guard page consumes no physical memory, but generates a
+segmentation fault or access violation on access to the virtual memory addresses
+within it.
+
+
+[heading fcontext_t]
+
+__boost_context__ provides the low leve lAPI boost_fcontext_t which is
+implemented in assembler to provide context swapping operations.
+boost_fcontext_t is the part to port to new platforms.
+
+[note Context switches do not preserve the signal mask on UNIX systems.]
+
+
+[section Other APIs ]
+
+[heading setjmp()/longjmp()]
+
+C99 defines `setjmp()`/`longjmp()` to provide non-local jumps but it does not
+require that ['longjmp()] preserves the current stack frame. Therefore, jumping
+into a function which was exited via a call to ['longjmp()] is undefined
+[footnote [@boost:/libs/context/doc/pdf/iso_c99.pdf ISO/IEC 9899:1999, 2005],
+7.13.2.1:2].
+
+
+[heading ucontext_t]
+
+Since POSIX.1-2003 `ucontext_t` is deprecated and was removed in POSIX.1-2008!
+The function signature of `makecontext()` is:
+
+ void makecontext(ucontext_t *ucp, void (*func)(), int argc, ...);
+
+The third argument of `makecontext()` specifies the number of integer arguments
+that follow which will require function pointer cast if `func` will accept those
+arguments which is undefined in C99
+[footnote [@boost:/libs/context/doc/pdf/iso_c99.pdf ISO/IEC 9899:1999, 2005],
+J.2].
+
+The arguments in the var-arg list are required to be integers, passing pointers
+in var-arg list is not guarantied to work, especially it will fail for
+architectures where pointers are larger than integers.
+
+`ucontext_t` preserves signal mask between context switches which involes system
+calls consuming a lot of CPU cycles (ucontext_t is slower by
+perfomance_link[factor 13x] relative to `boost_fcontext_t`).
+
+
+[heading Windows fibers]
+
+A drawback of Windows Fiber API is that `CreateFiber()` does not accept a
+pointer to user allocated stack space preventing the reuse of stacks for other
+context instances. Because the Windows Fiber API requires to call
+`ConvertThreadToFiber()` if `SwitchFiber()` is called for a thread which has not
+been converted to a fiber. For the same reason `ConvertFiberToThread()`
+must be called after return from `SwitchFiber()` if the thread was forced to be
+converted to a fiber before (which is inefficient).
+
+ if ( ! is_a_fiber() )
+ {
+ ConvertThreadToFiber( 0);
+ SwitchToFiber( ctx);
+ ConvertFiberToThread();
+ }
+
+If the condition `_WIN32_WINNT >= _WIN32_WINNT_VISTA` is met function
+`IsThreadAFiber()` is provided in order to detect if the current thread was
+already converted. Unfortunately Windows XP + SP 2/3 defines
+`_WIN32_WINNT >= _WIN32_WINNT_VISTA` without providing `IsThreadAFiber()`.
+
+[endsect]
+
+[endsect]

Added: trunk/libs/context/doc/reference.qbk
==============================================================================
--- (empty file)
+++ trunk/libs/context/doc/reference.qbk 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,43 @@
+[/
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt
+]
+
+[section:reference Reference]
+
+[heading ARM]
+
+* AAPCS ABI: [@boost:/libs/context/doc/pdf/arm-aapcs.pdf Procedure Call Standard for the ARM Architecture]
+* AAPCS/LINUX: [@boost:/libs/context/doc/pdf/arm-linux-aapcs.pdf ARM GNU/Linux Application Binary Interface Supplement]
+
+
+[heading MIPS]
+
+* O32 ABI: [@boost:/libs/context/doc/pdf/mips-o32.pdf SYSTEM V APPLICATION BINARY INTERFACE, MIPS RISC Processor Supplement]
+
+
+[heading PowerPC32]
+
+* SYSV ABI: [@boost:/libs/context/doc/pdf/ppc32-sysv.pdf SYSTEM V APPLICATION BINARY INTERFACE PowerPC Processor Supplement]
+
+
+[heading PowerPC64]
+
+* SYSV ABI: [@boost:/libs/context/doc/pdf/ppc64-sysv.pdf PowerPC User Instruction Set Architecture, Book I]
+
+
+[heading X86-32]
+
+* SYSV ABI: [@boost:/libs/context/doc/pdf/x86_32-sysv.pdf SYSTEM V APPLICATION BINARY INTERFACE, Intel386TM Architecture Processor Supplement]
+* MS PE: [@http://msdn.microsoft.com/en-us/library/k2b2ssfy.aspx Calling Conventions]
+
+
+[heading X86-64]
+
+* SYSV ABI: [@boost:/libs/context/doc/pdf/x86_64-sysv.pdf System V Application Binary Interface, AMD64 Architecture Processor Supplement]
+* MS PE: [@http://msdn.microsoft.com/en-us/library/7kcdt6fy%28VS.80%29.aspx x64 Software Conventions]
+
+
+[endsect]

Added: trunk/libs/context/doc/stack_ref.qbk
==============================================================================
--- (empty file)
+++ trunk/libs/context/doc/stack_ref.qbk 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,116 @@
+[/
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt
+]
+
+[section:stack Stack allocation]
+
+A __context__ requires a stack which will be allocated/deallocated
+by a __stack_allocator__.
+__boost_context__ uses `stack_allocator` by default but a
+customized `stack allocator` can be passed to the context constructor
+instead.
+If a context is constructed it invokes __stack_alloc__ function and by its
+destruction the stack gets released by __stack_dealloc__.
+
+[heading __stack_allocator_concept__]
+A __stack_allocator__ must satisfy the __stack_allocator_concept__ requirements
+shown in the following table, in which `a` is an object of a
+__stack_allocator__ type, `p` is a `void *`, and `s` is a `std::size_t`:
+
+[table
+ [[expression][return type][notes]]
+ [
+ [`a.allocate( s)`]
+ [`void *`]
+ [returns a pointer to `s` bytes allocated from the stack]
+ ]
+ [
+ [`a.deallocate( p, s)`]
+ [`void`]
+ [deallocates `s` bytes of memory beginning at `p`,
+ a pointer previously returned by `a.allocate()`]
+ ]
+]
+
+[important The implementation of `allocate()` might include logic to protect
+against exceeding the context's available stack size rather than leaving it as
+undefined behaviour.]
+
+[important Calling `deallocate()` with a pointer not returned by `allocate()`
+results in undefined behaviour.]
+
+[note The stack is not required to be aligned; alignment takes place inside
+`boost_fcontext_make()`.]
+
+
+[section:stack_allocator Class `stack_allocator`]
+
+__boost_context__ provides a __stack_allocator__ `stack_allocator` which models
+the __stack_allocator_concept__ concept.
+It appends a __guard_page__ to protect against exceeding the stack. If the guard
+page is accessed (read or write operation) a segmentation fault/access violation
+is generated by the operating system.
+
+[endsect]
+
+
+[section:stack_helper Helper functions]
+
+__boost_context__ provides easy access to the stack related limits defined by
+the environment.
+
+ std::size_t default_stacksize();
+
+ std::size_t minimum_stacksize();
+
+ std::size_t maximum_stacksize();
+
+ bool is_stack_unbound();
+
+ std::size_t pagesize();
+
+ std::size_t page_count( std::size_t stacksize);
+
+[heading `std::size_t default_stacksize()`]
+[variablelist
+[[Returns:] [Returns a default stack size, which may be platform specific.
+The present implementation returns a value of 256 kB.]]
+]
+
+[heading `std::size_t minimum_stacksize()`]
+[variablelist
+[[Returns:] [Returns the minimum size in bytes of stack defined by the environment.]]
+[[Throws:] [Nothing.]]
+]
+
+[heading `std::size_t maximum_stacksize()`]
+[variablelist
+[[Preconditions:] [`is_stack_unbound()` returns `false`.]]
+[[Returns:] [Returns the maximum size in bytes of stack defined by the environment.]]
+[[Throws:] [Nothing.]]
+]
+
+[heading `bool is_stack_unbound()`]
+[variablelist
+[[Returns:] [Returns `true` if the environment defines no limit for the size of a stack.]]
+[[Throws:] [Nothing.]]
+]
+
+[heading `std::size_t pagesize()`]
+[variablelist
+[[Returns:] [Returns how many bytes the operating system allocates for one page.]]
+[[Throws:] [Nothing.]]
+]
+
+[heading `std::size_t page_count( std::size_t stacksize)`]
+[variablelist
+[[Returns:] [Returns how many pages have to be allocated for a stack of `stacksize` bytes.]]
+[[Throws:] [Nothing.]]
+]
+
+[endsect]
+
+[endsect]

Added: trunk/libs/context/doc/tested.qbk
==============================================================================
--- (empty file)
+++ trunk/libs/context/doc/tested.qbk 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,74 @@
+[/
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt
+]
+
+[section:tested Tested Platforms]
+
+[table
+ [[Platform] [OS] [Compiler] [ABI]]
+ [
+ [ARM (ARM926EJ-S)]
+ [Debian GNU/Linux (Lenny)]
+ [GCC 4.4.4]
+ [ARM APCS (Linux)]
+ ]
+ [
+ [MIPS (MIPS 24K)]
+ [Debian GNU/Linux (Lenny)]
+ [GCC 4.3.2]
+ [O32]
+ ]
+ [
+ [MIPS (O2 / MIPS R5000)]
+ [Debian GNU/Linux (Lenny)]
+ [GCC 4.3.2]
+ [O32]
+ ]
+ [
+ [PowerPC (7400)]
+ [Debian GNU/Linux (Lenny)]
+ [GCC 4.3.2]
+ [SYSV]
+ ]
+ [
+ [X86_64 (Intel Core2 Quad)]
+ [Ubuntu GNU/Linux (Lucid Lynx)]
+ [GCC 4.4.3]
+ [SYSV]
+ ]
+ [
+ [X86_64]
+ [Windows 7]
+ [MS VC 10.0]
+ [PE]
+ ]
+ [
+ [I386]
+ [Debian GNU/Linux (Lenny)]
+ [GCC 4.4.3]
+ [SYSV]
+ ]
+ [
+ [I386]
+ [FreeBSD 8.0]
+ [GCC 4.2.1]
+ [SYSV]
+ ]
+ [
+ [I386]
+ [OpenSolaris 2009.06]
+ [GCC 4.3.2]
+ [SYSV]
+ ]
+ [
+ [I386]
+ [Windows XP]
+ [MSVC 9.0]
+ [PE]
+ ]
+]
+
+[endsect]

Added: trunk/libs/context/doc/todo.qbk
==============================================================================
--- (empty file)
+++ trunk/libs/context/doc/todo.qbk 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,12 @@
+[/
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt
+]
+
+[section:todo Todo]
+
+* provide support for SPARC
+
+[endsect]

Added: trunk/libs/context/example/Jamfile.v2
==============================================================================
--- (empty file)
+++ trunk/libs/context/example/Jamfile.v2 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,112 @@
+# Boost.Context Library Examples Jamfile
+
+# Copyright Oliver Kowalke 2009.
+# Distributed under the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE_1_0.txt or copy at
+# http://www.boost.org/LICENSE_1_0.txt)
+
+# For more information, see http://www.boost.org/
+
+import common ;
+import feature ;
+import indirect ;
+import modules ;
+import os ;
+import toolset ;
+
+if [ os.name ] = SOLARIS
+{
+ lib socket ;
+ lib nsl ;
+}
+else if [ os.name ] = NT
+{
+ lib ws2_32 ;
+ lib mswsock ;
+}
+else if [ os.name ] = HPUX
+{
+ lib ipv6 ;
+}
+
+project boost/context/example
+ : requirements
+ <library>/boost/context//boost_context
+ <library>/boost/system//boost_system
+ <library>/boost/thread//boost_thread
+ <define>BOOST_ALL_NO_LIB=1
+ <threading>multi
+ <os>SOLARIS:<library>socket
+ <os>SOLARIS:<library>nsl
+ <os>NT:<define>_WIN32_WINNT=0x0501
+ <os>NT,<toolset>gcc:<library>ws2_32
+ <os>NT,<toolset>gcc:<library>mswsock
+ <os>NT,<toolset>gcc-cygwin:<define>__USE_W32_SOCKETS
+ <os>HPUX,<toolset>gcc:<define>_XOPEN_SOURCE_EXTENDED
+ <os>HPUX:<library>ipv6
+ <link>shared
+ ;
+
+exe base_api
+ : base_api.cpp
+ ;
+
+exe exit
+ : exit.cpp
+ ;
+
+exe do_return
+ : do_return.cpp
+ ;
+
+exe link
+ : link.cpp
+ ;
+
+exe swap
+ : swap.cpp
+ ;
+
+exe unwind
+ : unwind.cpp
+ ;
+
+exe float
+ : float.cpp
+ ;
+
+exe transfer
+ : transfer.cpp
+ ;
+
+exe enumerate_string
+ : enumerator/enumerate_string.cpp
+ ;
+
+exe enumerate_tree
+ : enumerator/enumerate_tree.cpp
+ ;
+
+exe fringe
+ : enumerator/fringe.cpp
+ ;
+
+exe power
+ : enumerator/power.cpp
+ ;
+
+exe echo
+ : continuation/echo.cpp
+ ;
+
+exe parallel
+ : continuation/parallel.cpp
+ ;
+
+exe echo_client
+ : asio/echo_client.cpp
+ ;
+
+exe echo_server
+ : asio/echo_server.cpp
+ ;

Added: trunk/libs/context/example/asio/continuation.h
==============================================================================
--- (empty file)
+++ trunk/libs/context/example/asio/continuation.h 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,61 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef CONTINUATION_H
+#define CONTINUATION_H
+
+#include <boost/assert.hpp>
+#include <boost/bind.hpp>
+#include <boost/config.hpp>
+#include <boost/context/all.hpp>
+#include <boost/function.hpp>
+
+# if defined(BOOST_MSVC)
+# pragma warning(push)
+# pragma warning(disable:4355)
+# endif
+
+class continuation
+{
+private:
+ boost::contexts::context ctx_;
+ boost::function< void( continuation &) > fn_;
+ bool started_;
+
+ void trampoline_()
+ { fn_( * this); }
+
+public:
+ continuation( boost::function< void( continuation &) > const& fn) :
+ ctx_(
+ & continuation::trampoline_, this,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind, boost::contexts::return_to_caller),
+ fn_( fn), started_( false)
+ {}
+
+ void resume()
+ {
+ if ( ! started_)
+ {
+ started_ = true;
+ ctx_.start();
+ }
+ else ctx_.resume();
+ }
+
+ void suspend()
+ { ctx_.suspend(); }
+
+ bool is_complete() const
+ { return ctx_.is_complete(); }
+};
+
+# if defined(BOOST_MSVC)
+# pragma warning(pop)
+# endif
+
+#endif // CONTINUATION_H

Added: trunk/libs/context/example/asio/echo_client.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/example/asio/echo_client.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,63 @@
+//
+// blocking_tcp_echo_client.cpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2011 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <cstdlib>
+#include <cstring>
+#include <iostream>
+#include <boost/asio.hpp>
+
+using boost::asio::ip::tcp;
+
+enum { max_length = 1024 };
+
+int main(int argc, char* argv[])
+{
+ try
+ {
+ if (argc != 3)
+ {
+ std::cerr << "Usage: blocking_tcp_echo_client <host> <port>\n";
+ return 1;
+ }
+
+ {
+ boost::asio::io_service io_service;
+
+ tcp::resolver resolver(io_service);
+ tcp::resolver::query query(tcp::v4(), argv[1], argv[2]);
+ tcp::resolver::iterator iterator = resolver.resolve(query);
+
+ tcp::socket s(io_service);
+ s.connect(*iterator);
+
+ using namespace std; // For strlen.
+ std::cout << "Enter message: ";
+ char request[max_length];
+ std::cin.getline(request, max_length);
+ size_t request_length = strlen(request);
+ boost::asio::write(s, boost::asio::buffer(request, request_length));
+
+ char reply[max_length];
+ size_t reply_length = boost::asio::read(s,
+ boost::asio::buffer(reply, request_length));
+ std::cout << "Reply is: ";
+ std::cout.write(reply, reply_length);
+ std::cout << "\n";
+ }
+
+ std::cout << "Done" << std::endl;
+ }
+ catch (std::exception& e)
+ {
+ std::cerr << "Exception: " << e.what() << "\n";
+ }
+
+ return 0;
+}

Added: trunk/libs/context/example/asio/echo_server.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/example/asio/echo_server.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,106 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+// adapted version of echo-server example using coroutines from
+// Chris Kohlhoff: http://blog.think-async.com/2009/08/secret-sauce-revealed.html
+
+#include <cstdlib>
+#include <iostream>
+
+#include <boost/array.hpp>
+#include <boost/asio.hpp>
+#include <boost/bind.hpp>
+#include <boost/enable_shared_from_this.hpp>
+#include <boost/lexical_cast.hpp>
+#include <boost/shared_ptr.hpp>
+#include <boost/system/error_code.hpp>
+
+#include "continuation.h"
+
+class server : public boost::enable_shared_from_this< server >,
+ private continuation
+{
+private:
+ boost::asio::ip::tcp::acceptor acceptor_;
+ boost::system::error_code ec_;
+ std::size_t n_;
+
+ void do_()
+ {
+ for (;;)
+ {
+ boost::asio::ip::tcp::socket socket( acceptor_.get_io_service() );
+ acceptor_.async_accept( socket, boost::bind( & server::operator(), this->shared_from_this(), _1, 0) );
+ suspend();
+
+ while ( ! ec_)
+ {
+ boost::array< char, 1024 > buffer;
+
+ socket.async_read_some(
+ boost::asio::buffer( buffer),
+ boost::bind( & server::operator(), this->shared_from_this(), _1, _2) );
+ suspend();
+
+ if ( ec_) break;
+
+ boost::asio::async_write(
+ socket,
+ boost::asio::buffer( buffer, n_),
+ boost::bind( & server::operator(), this->shared_from_this(), _1, _2) );
+ suspend();
+ }
+ }
+ }
+
+ server( boost::asio::io_service & io_service, short port) :
+ continuation( boost::bind( & server::do_, this) ),
+ acceptor_( io_service, boost::asio::ip::tcp::endpoint( boost::asio::ip::tcp::v4(), port) ),
+ ec_(), n_( 0)
+ {}
+
+public:
+ typedef boost::shared_ptr< server > ptr_t;
+
+ static ptr_t create( boost::asio::io_service & io_service, short port)
+ { return ptr_t( new server( io_service, port) ); }
+
+ void operator()( boost::system::error_code ec, size_t n)
+ {
+ ec_ = ec;
+ n_ = n;
+ resume();
+ }
+};
+
+int main( int argc, char * argv[])
+{
+ try
+ {
+ if ( argc != 2)
+ {
+ std::cerr << "Usage: echo_server <port>\n";
+ return 1;
+ }
+ {
+ boost::asio::io_service io_service;
+ io_service.post(
+ boost::bind(
+ & server::operator(),
+ server::create( io_service, boost::lexical_cast< short >( argv[1]) ),
+ boost::system::error_code(), 0) );
+ io_service.run();
+ }
+ std::cout << "Done" << std::endl;
+
+ return EXIT_SUCCESS;
+ }
+ catch ( std::exception const& e)
+ { std::cerr << "Exception: " << e.what() << std::endl; }
+
+ return EXIT_FAILURE;
+}
+

Added: trunk/libs/context/example/base_api.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/example/base_api.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,55 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <vector>
+
+#include <boost/assert.hpp>
+#include <boost/context/all.hpp>
+
+boost_fcontext_t fcm, fc1, fc2;
+
+void f1( intptr_t p)
+{
+ (void) p;
+ fprintf(stderr,"f1() stated\n");
+ fprintf(stderr,"f1: call boost_fcontext_jump( & fc1, & fc2)\n");
+ boost_fcontext_jump( & fc1, & fc2, 0);
+ fprintf(stderr,"f1() returns\n");
+}
+
+void f2( intptr_t p)
+{
+ (void) p;
+ fprintf(stderr,"f2() stated\n");
+ fprintf(stderr,"f2: call boost_fcontext_jump( & fc2, & fc1)\n");
+ boost_fcontext_jump( & fc2, & fc1, 0);
+ BOOST_ASSERT( false && ! "f2() never returns");
+}
+
+int main( int argc, char * argv[])
+{
+ boost::contexts::stack_allocator alloc;
+
+ fc1.fc_stack.ss_base = alloc.allocate(262144);
+ fc1.fc_stack.ss_limit =
+ static_cast< char * >( fc1.fc_stack.ss_base) - 262144;
+ fc1.fc_link = & fcm;
+ boost_fcontext_make( & fc1, f1, 0);
+
+ fc2.fc_stack.ss_base = alloc.allocate(262144);
+ fc2.fc_stack.ss_limit =
+ static_cast< char * >( fc2.fc_stack.ss_base) - 262144;
+ boost_fcontext_make( & fc2, f2, 0);
+
+ fprintf(stderr,"main: call boost_fcontext_start( & fcm, & fc1)\n");
+ boost_fcontext_start( & fcm, & fc1);
+
+ fprintf( stderr, "main() returns\n");
+ return EXIT_SUCCESS;
+}

Added: trunk/libs/context/example/continuation/continuation.h
==============================================================================
--- (empty file)
+++ trunk/libs/context/example/continuation/continuation.h 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,68 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef CONTINUATION_H
+#define CONTINUATION_H
+
+#include <boost/assert.hpp>
+#include <boost/bind.hpp>
+#include <boost/config.hpp>
+#include <boost/context/all.hpp>
+#include <boost/function.hpp>
+
+# if defined(BOOST_MSVC)
+# pragma warning(push)
+# pragma warning(disable:4355)
+# endif
+
+class continuation
+{
+private:
+ boost::contexts::context ctx_;
+ boost::function< void( continuation &) > fn_;
+ bool started_;
+
+ void trampoline_()
+ { fn_( * this); }
+
+public:
+ continuation( boost::function< void( continuation &) > const& fn) :
+ ctx_(
+ & continuation::trampoline_, this,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind, boost::contexts::return_to_caller),
+ fn_( fn), started_( false)
+ {}
+
+ void resume()
+ {
+ if ( ! started_)
+ {
+ started_ = true;
+ ctx_.start();
+ }
+ else ctx_.resume();
+ }
+
+ void suspend()
+ { ctx_.suspend(); }
+
+ void join( boost::function< void( continuation &) > const& fn)
+ {
+ continuation c( fn);
+ while ( ! c.is_complete() )
+ c.resume();
+ }
+
+ bool is_complete() const
+ { return ctx_.is_complete(); }
+};
+
+# if defined(BOOST_MSVC)
+# pragma warning(pop)
+# endif
+
+#endif // CONTINUATION_H

Added: trunk/libs/context/example/continuation/echo.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/example/continuation/echo.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,43 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <cstdlib>
+#include <iostream>
+
+#include <boost/bind.hpp>
+
+#include "continuation.h"
+
+void echo( continuation & c, int i)
+{
+ std::cout << i;
+ c.suspend();
+}
+
+void runit( continuation & c)
+{
+ std::cout << "started! ";
+ for ( int i = 0; i < 10; ++i)
+ {
+ c.join( boost::bind( echo, _1, i) );
+ c.suspend();
+ }
+}
+
+int main( int argc, char * argv[])
+{
+ {
+ continuation c( boost::bind( runit, _1) );
+ while ( ! c.is_complete() ) {
+ std::cout << "-";
+ c.resume();
+ }
+ }
+
+ std::cout << "\nDone" << std::endl;
+
+ return EXIT_SUCCESS;
+}

Added: trunk/libs/context/example/continuation/parallel.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/example/continuation/parallel.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,50 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <cstdlib>
+#include <iostream>
+
+#include <boost/bind.hpp>
+
+#include "continuation.h"
+
+void first( continuation & c)
+{
+ std::cout << "started first! ";
+ for ( int i = 0; i < 10; ++i)
+ {
+ c.suspend();
+ std::cout << "a" << i;
+ }
+}
+
+void second( continuation & c)
+{
+ std::cout << "started second! ";
+ for ( int i = 0; i < 10; ++i)
+ {
+ c.suspend();
+ std::cout << "b" << i;
+ }
+}
+
+int main( int argc, char * argv[])
+{
+ {
+ continuation c1( boost::bind( first, _1) );
+ continuation c2( boost::bind( second, _1) );
+ while ( ! c1.is_complete() && ! c2.is_complete() ) {
+ c1.resume();
+ std::cout << " ";
+ c2.resume();
+ std::cout << " ";
+ }
+ }
+
+ std::cout << "\nDone" << std::endl;
+
+ return EXIT_SUCCESS;
+}

Added: trunk/libs/context/example/do_return.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/example/do_return.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,33 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <cstdlib>
+#include <iostream>
+#include <string>
+
+#include <boost/context/all.hpp>
+#include <boost/move/move.hpp>
+
+void fn()
+{
+ std::cout << "inside function fn(): fn() returns return to main()" << std::endl;
+}
+
+int main( int argc, char * argv[])
+{
+ {
+ boost::contexts::context ctx(
+ fn,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind, boost::contexts::return_to_caller);
+
+ ctx.start();
+ }
+
+ std::cout << "Done" << std::endl;
+
+ return EXIT_SUCCESS;
+}

Added: trunk/libs/context/example/enumerator/enumerate_string.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/example/enumerator/enumerate_string.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,48 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <cstdlib>
+#include <iostream>
+#include <string>
+
+#include "enumerator.h"
+
+class string_enumerator : public enumerator< char >
+{
+private:
+ void enumerate()
+ {
+ const char * c( str_.c_str() );
+ while ( '\0' != * c) {
+ const char tmp( * c);
+ yield_return( tmp);
+ ++c;
+ }
+ }
+
+ std::string const& str_;
+
+public:
+ string_enumerator( std::string const& str) :
+ str_( str)
+ {}
+};
+
+int main( int argc, char * argv[])
+{
+ {
+ std::string str("Hello World!");
+ string_enumerator se( str);
+ char tmp;
+ while ( se.get( tmp) ) {
+ std::cout << tmp << " ";
+ }
+ }
+
+ std::cout << "\nDone" << std::endl;
+
+ return EXIT_SUCCESS;
+}

Added: trunk/libs/context/example/enumerator/enumerate_tree.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/example/enumerator/enumerate_tree.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,37 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <cstddef>
+#include <cstdlib>
+#include <iostream>
+#include <string>
+
+#include "tree.h"
+
+node::ptr_t create_tree()
+{
+ return branch::create(
+ leaf::create( "A"),
+ branch::create(
+ leaf::create( "B"),
+ leaf::create( "C") ) );
+}
+
+int main( int argc, char * argv[])
+{
+ {
+ node::ptr_t root = create_tree();
+ tree_enumerator te( root);
+ std::string value;
+ while ( te.get( value) ) {
+ std::cout << value << " ";
+ }
+ }
+
+ std::cout << "\nDone" << std::endl;
+
+ return EXIT_SUCCESS;
+}

Added: trunk/libs/context/example/enumerator/enumerator.h
==============================================================================
--- (empty file)
+++ trunk/libs/context/example/enumerator/enumerator.h 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,85 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef ENUMERATOR_H
+#define ENUMERATOR_H
+
+#include <boost/bind.hpp>
+#include <boost/config.hpp>
+
+#include <boost/context/all.hpp>
+
+# if defined(BOOST_MSVC)
+# pragma warning(push)
+# pragma warning(disable:4355)
+# endif
+
+template< typename T >
+class enumerator {
+private:
+ boost::contexts::context ctx_;
+ bool complete_;
+ bool do_unwind_;
+ bool started_;
+
+ static void run( enumerator * self)
+ { self->enumerate(); }
+
+protected:
+ virtual void enumerate() = 0;
+
+ void yield_return( T const& v)
+ {
+ intptr_t vp = reinterpret_cast< intptr_t >( & v);
+ ctx_.suspend( vp);
+ }
+
+ void yield_break()
+ {
+ complete_ = true;
+ ctx_.suspend();
+ }
+
+public:
+ enumerator( bool do_unwind = true):
+ ctx_(
+ & enumerator::run, this,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind, boost::contexts::return_to_caller),
+ complete_( false),
+ do_unwind_( do_unwind),
+ started_( false)
+ {}
+
+ ~enumerator()
+ {
+ if ( do_unwind_ && ! ctx_.is_complete() )
+ ctx_.unwind_stack();
+ }
+
+ bool get( T & result)
+ {
+ intptr_t vp = 0;
+ if ( ! started_)
+ {
+ started_ = true;
+ vp = ctx_.start();
+ }
+ else
+ {
+ vp = ctx_.resume();
+ }
+ if ( vp) result = * reinterpret_cast< T * >( vp);
+ return ! ( complete_ || ctx_.is_complete() );
+ }
+};
+
+# if defined(BOOST_MSVC)
+# pragma warning(pop)
+# endif
+
+
+#endif // ENUMERATOR_H

Added: trunk/libs/context/example/enumerator/fringe.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/example/enumerator/fringe.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,83 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <cstddef>
+#include <cstdlib>
+#include <iostream>
+#include <string>
+#include <utility>
+
+#include "tree.h"
+
+bool match_trees( tree_enumerator & te1, tree_enumerator & te2)
+{
+ std::string v1;
+ std::string v2;
+
+ bool res1 = te1.get( v1);
+ bool res2 = te2.get( v2);
+
+ if ( ! res1 && ! res2) return true;
+ if ( ! res1 || ! res2) return false;
+ if ( v1 == v2) return match_trees( te1, te2);
+ else return false;
+}
+
+std::pair< node::ptr_t, node::ptr_t > create_eq_trees()
+{
+ branch::ptr_t tree1 = branch::create(
+ leaf::create( "A"),
+ branch::create(
+ leaf::create( "B"),
+ leaf::create( "C") ) );
+
+ branch::ptr_t tree2 = branch::create(
+ branch::create(
+ leaf::create( "A"),
+ leaf::create( "B") ),
+ leaf::create( "C") );
+
+ return std::make_pair( tree1, tree2);
+}
+
+std::pair< node::ptr_t, node::ptr_t > create_diff_trees()
+{
+ branch::ptr_t tree1 = branch::create(
+ leaf::create( "A"),
+ branch::create(
+ leaf::create( "B"),
+ leaf::create( "C") ) );
+
+ branch::ptr_t tree2 = branch::create(
+ branch::create(
+ leaf::create( "A"),
+ leaf::create( "X") ),
+ leaf::create( "C") );
+
+ return std::make_pair( tree1, tree2);
+}
+
+int main()
+{
+ {
+ std::pair< node::ptr_t, node::ptr_t > pt = create_eq_trees();
+ tree_enumerator te1( pt.first);
+ tree_enumerator te2( pt.second);
+ bool result = match_trees( te1, te2);
+ std::cout << std::boolalpha << "eq. trees matched == " << result << std::endl;
+ }
+ {
+ std::pair< node::ptr_t, node::ptr_t > pt = create_diff_trees();
+ tree_enumerator te1( pt.first);
+ tree_enumerator te2( pt.second);
+ bool result = match_trees( te1, te2);
+ std::cout << std::boolalpha << "diff. trees matched == " << result << std::endl;
+ }
+
+ std::cout << "Done" << std::endl;
+
+ return EXIT_SUCCESS;
+}

Added: trunk/libs/context/example/enumerator/power.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/example/enumerator/power.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,48 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <cstdlib>
+#include <iostream>
+
+#include "enumerator.h"
+
+class power : public enumerator< int >
+{
+private:
+ void enumerate()
+ {
+ int counter = 0;
+ int result = 1;
+ while ( counter++ < exponent_)
+ {
+ result = result * number_;
+ yield_return( result);
+ }
+ }
+
+ int number_;
+ int exponent_;
+
+public:
+ power( int number, int exponent) :
+ number_( number), exponent_( exponent)
+ {}
+};
+
+int main()
+{
+ {
+ power pw( 2, 8);
+ int i;
+ while ( pw.get( i) ) {
+ std::cout << i << " ";
+ }
+ }
+
+ std::cout << "\nDone" << std::endl;
+
+ return EXIT_SUCCESS;
+}

Added: trunk/libs/context/example/enumerator/tree.h
==============================================================================
--- (empty file)
+++ trunk/libs/context/example/enumerator/tree.h 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,116 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef TREE_H
+#define TREE_H
+
+#include <cstddef>
+#include <string>
+
+#include <boost/assert.hpp>
+#include <boost/config.hpp>
+#include <boost/intrusive_ptr.hpp>
+
+#include "enumerator.h"
+
+# if defined(BOOST_MSVC)
+# pragma warning(push)
+# pragma warning(disable:4355)
+# endif
+
+struct branch;
+struct leaf;
+
+struct visitor
+{
+ virtual ~visitor() {};
+
+ virtual void visit( branch & b) = 0;
+ virtual void visit( leaf & l) = 0;
+};
+
+struct node
+{
+ typedef boost::intrusive_ptr< node > ptr_t;
+
+ std::size_t use_count;
+
+ node() :
+ use_count( 0)
+ {}
+
+ virtual ~node() {}
+
+ virtual void accept( visitor & v) = 0;
+
+ friend inline void intrusive_ptr_add_ref( node * p)
+ { ++p->use_count; }
+
+ friend inline void intrusive_ptr_release( node * p)
+ { if ( 0 == --p->use_count) delete p; }
+};
+
+struct branch : public node
+{
+ node::ptr_t left;
+ node::ptr_t right;
+
+ static ptr_t create( node::ptr_t left_, node::ptr_t right_)
+ { return ptr_t( new branch( left_, right_) ); }
+
+ branch( node::ptr_t left_, node::ptr_t right_) :
+ left( left_), right( right_)
+ {}
+
+ void accept( visitor & v)
+ { v.visit( * this); }
+};
+
+struct leaf : public node
+{
+ std::string value;
+
+ static ptr_t create( std::string const& value_)
+ { return ptr_t( new leaf( value_) ); }
+
+ leaf( std::string const& value_) :
+ value( value_)
+ {}
+
+ void accept( visitor & v)
+ { v.visit( * this); }
+};
+
+class tree_enumerator : public enumerator< std::string >,
+ public visitor
+{
+private:
+ void enumerate()
+ { root_->accept( * this); }
+
+ node::ptr_t root_;
+
+public:
+ tree_enumerator( node::ptr_t root) :
+ root_( root)
+ { BOOST_ASSERT( root_); }
+
+ void visit( branch & b)
+ {
+ if ( b.left) b.left->accept( * this);
+ if ( b.right) b.right->accept( * this);
+ }
+
+ void visit( leaf & l)
+ { yield_return( l.value); }
+};
+
+# if defined(BOOST_MSVC)
+# pragma warning(pop)
+# endif
+
+
+#endif // TREE_H

Added: trunk/libs/context/example/exit.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/example/exit.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,33 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <cstdlib>
+#include <iostream>
+#include <string>
+
+#include <boost/context/all.hpp>
+#include <boost/move/move.hpp>
+
+void fn()
+{
+ std::cout << "inside function fn(): when fn() returns ::exit() will be called; no return to main()" << std::endl;
+}
+
+int main( int argc, char * argv[])
+{
+ {
+ boost::contexts::context ctx(
+ fn,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind, boost::contexts::exit_application);
+
+ ctx.start();
+ }
+
+ std::cout << "Done" << std::endl;
+
+ return EXIT_SUCCESS;
+}

Added: trunk/libs/context/example/float.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/example/float.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,31 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <cstdlib>
+#include <iostream>
+#include <string>
+
+#include <boost/context/all.hpp>
+#include <boost/move/move.hpp>
+
+void fn( double d)
+{
+ d += 3.45;
+ std::cout << "d == " << d << std::endl;
+}
+
+int main( int argc, char * argv[])
+{
+ boost::contexts::context ctx(
+ fn, 7.34,
+ boost::contexts::default_stacksize(),
+ boost::contexts::stack_unwind, boost::contexts::return_to_caller);
+ ctx.start();
+
+ std::cout << "Done" << std::endl;
+
+ return EXIT_SUCCESS;
+}

Added: trunk/libs/context/example/link.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/example/link.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,51 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <cstdlib>
+#include <iostream>
+#include <string>
+
+#include <boost/context/all.hpp>
+
+void fn1()
+{
+ std::cout << "inside fn1(): when fn1() returns fn2() of next context (linked) will be entered" << std::endl;
+}
+
+boost::contexts::context ctx2;
+
+void fn2()
+{
+ std::cout << "first time inside fn2()" << std::endl;
+ ctx2.suspend();
+ std::cout << "second time inside fn2(), returns to main()" << std::endl;
+}
+
+int main( int argc, char * argv[])
+{
+ {
+ ctx2 = boost::contexts::context(
+ fn2,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind, boost::contexts::return_to_caller);
+ boost::contexts::context ctx1(
+ fn1,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind,
+ ctx2);
+
+ ctx1.start();
+ }
+
+ std::cout << "main(): ctx1 is destructed\n";
+
+ std::cout << "main(): resume ctx2\n";
+ ctx2.resume();
+
+ std::cout << "Done" << std::endl;
+
+ return EXIT_SUCCESS;
+}

Added: trunk/libs/context/example/swap.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/example/swap.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,41 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <cstdlib>
+#include <iostream>
+#include <string>
+
+#include <boost/context/all.hpp>
+#include <boost/move/move.hpp>
+
+int x = 7;
+void fn( int);
+
+boost::contexts::context ctx( fn, x, boost::contexts::default_stacksize(), boost::contexts::no_stack_unwind, boost::contexts::return_to_caller);
+
+void fn( int j)
+{
+ for( int i = 0; i < j; ++i)
+ {
+ std::cout << "fn(): local variable i == " << i << std::endl;
+ ctx.suspend();
+ }
+}
+
+int main( int argc, char * argv[])
+{
+ std::cout << "main() calls context ctx" << std::endl;
+ ctx.start();
+ while ( ! ctx.is_complete() )
+ {
+ std::cout << "main() calls context ctx" << std::endl;
+ ctx.resume();
+ }
+
+ std::cout << "Done" << std::endl;
+
+ return EXIT_SUCCESS;
+}

Added: trunk/libs/context/example/transfer.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/example/transfer.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,53 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <cstdlib>
+#include <iostream>
+#include <string>
+
+#include <boost/context/all.hpp>
+
+
+boost::contexts::context ctx;
+
+void fn()
+{
+ int i = 7;
+ std::cout << "fn(): local variable i == " << i << std::endl;
+
+ // save current context
+ // transfer execution control back to caller
+ // pass pointer to local variable i
+ intptr_t vp = ctx.suspend( i);
+ int j = vp;
+
+ std::cout << "transfered value: " << j << std::endl;
+}
+
+int main( int argc, char * argv[])
+{
+ ctx = boost::contexts::context( fn,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind,
+ boost::contexts::return_to_caller);
+
+ std::cout << "main() calls context ctx" << std::endl;
+
+ // start the context ctx for the first time
+ // enter fn()
+ intptr_t vp = ctx.start();
+ int x = vp;
+
+ std::cout << "transfered value: " << x << std::endl;
+ x = 10;
+
+ // ctx.suspend() was called so we returned from start()
+ ctx.resume( x);
+
+ std::cout << "Done" << std::endl;
+
+ return EXIT_SUCCESS;
+}

Added: trunk/libs/context/example/unwind.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/example/unwind.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,55 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <cstdlib>
+#include <iostream>
+#include <string>
+
+#include <boost/context/all.hpp>
+
+boost::contexts::context ctx;
+
+struct X
+{
+ X()
+ { std::cout << "X()" << std::endl; }
+
+ ~X()
+ { std::cout << "~X()" << std::endl; }
+};
+
+void fn()
+{
+ X x;
+
+ for( int i = 0;; ++i)
+ {
+ std::cout << "fn(): " << i << std::endl;
+ ctx.suspend();
+ }
+}
+
+int main( int argc, char * argv[])
+{
+ ctx = boost::contexts::context(
+ fn,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind, boost::contexts::return_to_caller);
+ ctx.start();
+ for ( int i = 0; i < 4; ++i)
+ {
+ ctx.resume();
+ }
+
+ std::cout << "ctx is complete: " << std::boolalpha << ctx.is_complete() << "\n";
+ std::cout << "call ctx.unwind_stack()" << std::endl;
+ ctx.unwind_stack();
+ std::cout << "ctx is complete: " << std::boolalpha << ctx.is_complete() << "\n";
+
+ std::cout << "Done" << std::endl;
+
+ return EXIT_SUCCESS;
+}

Added: trunk/libs/context/performance/Jamfile.v2
==============================================================================
--- (empty file)
+++ trunk/libs/context/performance/Jamfile.v2 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,66 @@
+
+# Copyright Oliver Kowalke 2009.
+# Distributed under the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE_1_0.txt or copy at
+# http://www.boost.org/LICENSE_1_0.txt)
+
+# For more information, see http://www.boost.org/
+
+import common ;
+import feature ;
+import indirect ;
+import modules ;
+import os ;
+import toolset ;
+
+project boost/context/performance
+ : requirements
+ <library>/boost/program_options//boost_program_options
+ <library>/boost/thread//boost_thread
+ <library>/boost/system//boost_system
+ <library>/boost/context//boost_context
+ <link>static
+ <threading>multi
+ ;
+
+alias sources
+ : performance.cpp
+ bind_processor_aix.cpp
+ : <target-os>aix
+ ;
+
+alias sources
+ : performance.cpp
+ bind_processor_freebsd.cpp
+ : <target-os>freebsd
+ ;
+
+alias sources
+ : performance.cpp
+ bind_processor_hpux.cpp
+ : <target-os>hpux
+ ;
+
+alias sources
+ : performance.cpp
+ bind_processor_linux.cpp
+ : <target-os>linux
+ ;
+
+alias sources
+ : performance.cpp
+ bind_processor_solaris.cpp
+ : <target-os>solaris
+ ;
+
+alias sources
+ : performance.cpp
+ bind_processor_windows.cpp
+ : <target-os>windows
+ ;
+
+explicit sources ;
+
+exe performance
+ : sources
+ ;

Added: trunk/libs/context/performance/bind_processor.hpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/performance/bind_processor.hpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,12 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BIND_TO_PROCESSOR_H
+#define BIND_TO_PROCESSOR_H
+
+void bind_to_processor( unsigned int n);
+
+#endif // BIND_TO_PROCESSOR_H

Added: trunk/libs/context/performance/bind_processor_aix.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/performance/bind_processor_aix.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,33 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include "bind_processor.hpp"
+
+extern "C"
+{
+#include <sys/processor.h>
+#include <sys/thread.h>
+}
+
+#include <boost/assert.hpp>
+#include <boost/thread.hpp>
+#include <boost/system/system_error.hpp>
+
+#include <boost/config/abi_prefix.hpp>
+
+void bind_to_processor( unsigned int n)
+{
+ BOOST_ASSERT( n >= 0);
+ BOOST_ASSERT( n < boost::thread::hardware_concurrency() );
+
+ if ( ::bindprocessor( BINDTHREAD, ::thread_self(), static_cast< cpu_t >( n) ) == -1)
+ throw boost::system::system_error(
+ boost::system::error_code(
+ errno,
+ boost::system::system_category() ) );
+}
+
+#include <boost/config/abi_suffix.hpp>

Added: trunk/libs/context/performance/bind_processor_freebsd.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/performance/bind_processor_freebsd.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,37 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include "bind_processor.hpp"
+
+extern "C"
+{
+#include <sys/param.h>
+#include <sys/cpuset.h>
+}
+
+#include <boost/assert.hpp>
+#include <boost/thread.hpp>
+#include <boost/system/system_error.hpp>
+
+#include <boost/config/abi_prefix.hpp>
+
+void bind_to_processor( unsigned int n)
+{
+ BOOST_ASSERT( n >= 0);
+ BOOST_ASSERT( n < boost::thread::hardware_concurrency() );
+
+ cpuset_t cpuset;
+ CPU_ZERO( & cpuset);
+ CPU_SET( n, & cpuset);
+
+ if ( ::cpuset_setaffinity( CPU_LEVEL_WHICH, CPU_WHICH_TID, -1, sizeof( cpuset), & cpuset) == -1)
+ throw boost::system::system_error(
+ boost::system::error_code(
+ errno,
+ boost::system::system_category() ) );
+}
+
+#include <boost/config/abi_suffix.hpp>

Added: trunk/libs/context/performance/bind_processor_hpux.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/performance/bind_processor_hpux.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,39 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include "bind_processor.hpp"
+
+extern "C"
+{
+#include <sys/pthread.h>
+}
+
+#include <boost/assert.hpp>
+#include <boost/thread.hpp>
+#include <boost/system/system_error.hpp>
+
+#include <boost/config/abi_prefix.hpp>
+
+void bind_to_processor( unsigned int n)
+{
+ BOOST_ASSERT( n >= 0);
+ BOOST_ASSERT( n < boost::thread::hardware_concurrency() );
+
+ ::pthread_spu_t spu;
+ int errno_(
+ ::pthread_processor_bind_np(
+ PTHREAD_BIND_FORCED_NP,
+ & spu,
+ static_cast< pthread_spu_t >( n),
+ PTHREAD_SELFTID_NP) );
+ if ( errno_ != 0)
+ throw boost::system::system_error(
+ boost::system::error_code(
+ errno_,
+ boost::system::system_category() ) );
+}
+
+#include <boost/config/abi_suffix.hpp>

Added: trunk/libs/context/performance/bind_processor_linux.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/performance/bind_processor_linux.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,39 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include "bind_processor.hpp"
+
+extern "C"
+{
+#include <pthread.h>
+#include <sched.h>
+}
+
+#include <boost/assert.hpp>
+#include <boost/thread.hpp>
+#include <boost/system/system_error.hpp>
+
+#include <boost/config/abi_prefix.hpp>
+
+void bind_to_processor( unsigned int n)
+{
+ BOOST_ASSERT( n >= 0);
+ BOOST_ASSERT( n < CPU_SETSIZE);
+ BOOST_ASSERT( n < boost::thread::hardware_concurrency() );
+
+ cpu_set_t cpuset;
+ CPU_ZERO( & cpuset);
+ CPU_SET( n, & cpuset);
+
+ int errno_( ::pthread_setaffinity_np( ::pthread_self(), sizeof( cpuset), & cpuset) );
+ if ( errno_ != 0)
+ throw boost::system::system_error(
+ boost::system::error_code(
+ errno_,
+ boost::system::system_category() ) );
+}
+
+#include <boost/config/abi_suffix.hpp>

Added: trunk/libs/context/performance/bind_processor_solaris.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/performance/bind_processor_solaris.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,34 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include "bind_processor.hpp"
+
+extern "C"
+{
+#include <sys/types.h>
+#include <sys/processor.h>
+#include <sys/procset.h>
+}
+
+#include <boost/assert.hpp>
+#include <boost/thread.hpp>
+#include <boost/system/system_error.hpp>
+
+#include <boost/config/abi_prefix.hpp>
+
+void bind_to_processor( unsigned int n)
+{
+ BOOST_ASSERT( n >= 0);
+ BOOST_ASSERT( n < boost::thread::hardware_concurrency() );
+
+ if ( ::processor_bind( P_LWPID, P_MYID, static_cast< processorid_t >( n), 0) == -1)
+ throw boost::system::system_error(
+ boost::system::error_code(
+ errno,
+ boost::system::system_category() ) );
+}
+
+#include <boost/config/abi_suffix.hpp>

Added: trunk/libs/context/performance/bind_processor_windows.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/performance/bind_processor_windows.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,32 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include "bind_processor.hpp"
+
+extern "C"
+{
+#include <windows.h>
+}
+
+#include <boost/assert.hpp>
+#include <boost/thread.hpp>
+#include <boost/system/system_error.hpp>
+
+#include <boost/config/abi_prefix.hpp>
+
+void bind_to_processor( unsigned int n)
+{
+ BOOST_ASSERT( n >= 0);
+ BOOST_ASSERT( n < boost::thread::hardware_concurrency() );
+
+ if ( ::SetThreadAffinityMask( ::GetCurrentThread(), ( DWORD_PTR)1 << n) == 0)
+ throw boost::system::system_error(
+ boost::system::error_code(
+ ::GetLastError(),
+ boost::system::system_category() ) );
+}
+
+#include <boost/config/abi_suffix.hpp>

Added: trunk/libs/context/performance/performance.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/performance/performance.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,137 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <cstdio>
+#include <cstdlib>
+#include <iostream>
+#include <stdexcept>
+
+#include <boost/assert.hpp>
+#include <boost/bind.hpp>
+#include <boost/context/all.hpp>
+#include <boost/program_options.hpp>
+
+#include "bind_processor.hpp"
+#include "performance.hpp"
+
+namespace po = boost::program_options;
+
+boost::contexts::context c;
+
+void fn()
+{ c.suspend(); }
+
+void test_creation( unsigned int iterations)
+{
+ cycle_t total( 0);
+ cycle_t overhead( get_overhead() );
+ std::cout << "overhead for rdtsc == " << overhead << " cycles" << std::endl;
+
+ // cache warm-up
+ {
+ c = boost::contexts::context(
+ fn,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind, boost::contexts::return_to_caller);
+ }
+
+ for ( unsigned int i = 0; i < iterations; ++i)
+ {
+ cycle_t start( get_cycles() );
+ c = boost::contexts::context(
+ fn,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind, boost::contexts::return_to_caller);
+ cycle_t diff( get_cycles() - start);
+ diff -= overhead;
+ BOOST_ASSERT( diff >= 0);
+ total += diff;
+ }
+ std::cout << "average of " << total/iterations << " cycles per creation" << std::endl;
+}
+
+void test_switching( unsigned int iterations)
+{
+ cycle_t total( 0);
+ cycle_t overhead( get_overhead() );
+ std::cout << "overhead for rdtsc == " << overhead << " cycles" << std::endl;
+
+ // cache warum-up
+ {
+ c = boost::contexts::context(
+ fn,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind, boost::contexts::return_to_caller);
+ c.start();
+ c.resume();
+ }
+
+ for ( unsigned int i = 0; i < iterations; ++i)
+ {
+ c = boost::contexts::context(
+ fn,
+ boost::contexts::default_stacksize(),
+ boost::contexts::no_stack_unwind, boost::contexts::return_to_caller);
+ cycle_t start( get_cycles() );
+ c.start();
+ cycle_t diff( get_cycles() - start);
+
+ // we have two jumps and two measuremt-overheads
+ diff -= overhead; // overhead of measurement
+ diff /= 2; // 2x jump_to c1->c2 && c2->c1
+
+ BOOST_ASSERT( diff >= 0);
+ total += diff;
+ }
+ std::cout << "average of " << total/iterations << " cycles per switch" << std::endl;
+}
+
+int main( int argc, char * argv[])
+{
+ try
+ {
+ unsigned int iterations( 0);
+
+ po::options_description desc("allowed options");
+ desc.add_options()
+ ("help,h", "help message")
+ ("creating,c", "test creation")
+ ("switching,s", "test switching")
+ ("iterations,i", po::value< unsigned int >( & iterations), "iterations");
+
+ po::variables_map vm;
+ po::store(
+ po::parse_command_line(
+ argc,
+ argv,
+ desc),
+ vm);
+ po::notify( vm);
+
+ if ( vm.count("help") )
+ {
+ std::cout << desc << std::endl;
+ return EXIT_SUCCESS;
+ }
+
+ if ( 0 >= iterations) throw std::invalid_argument("iterations must be greater than zero");
+
+ bind_to_processor( 0);
+
+ if ( vm.count("creating") )
+ test_creation( iterations);
+
+ if ( vm.count("switching") )
+ test_switching( iterations);
+
+ return EXIT_SUCCESS;
+ }
+ catch ( std::exception const& e)
+ { std::cerr << "exception: " << e.what() << std::endl; }
+ catch (...)
+ { std::cerr << "unhandled exception" << std::endl; }
+ return EXIT_FAILURE;
+}

Added: trunk/libs/context/performance/performance.hpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/performance/performance.hpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,26 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef PERFORMANCE_H
+#define PERFORMANCE_H
+
+// msvc/icc, i386
+#if defined(_MSC_VER) && defined(_M_IX86)
+#include "performance_msvc_i386.hpp"
+
+// gcc/icc, i386
+#elif defined(__GNUC__) && defined(__i386__)
+#include "performance_gcc_i386.hpp"
+
+// gcc/icc, x86_64
+#elif defined(__GNUC__) && defined(__x86_64__)
+#include "performance_gcc_x86-64.hpp"
+
+#else
+#error "this platform is not supported"
+#endif
+
+#endif // PERFORMANCE_H

Added: trunk/libs/context/performance/performance_gcc_i386.hpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/performance/performance_gcc_i386.hpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,62 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef PERFORMANCE_GCC_I386_H
+#define PERFORMANCE_GCC_I386_H
+
+#include <algorithm>
+#include <cstddef>
+#include <vector>
+
+#include <boost/assert.hpp>
+#include <boost/bind.hpp>
+#include <boost/cstdint.hpp>
+
+typedef boost::uint64_t cycle_t;
+
+inline
+cycle_t get_cycles()
+{
+ boost::uint32_t res[2];
+
+ __asm__ __volatile__ (
+ "xorl %%eax, %%eax\n"
+ "cpuid\n"
+ ::: "%eax", "%ebx", "%ecx", "%edx"
+ );
+ __asm__ __volatile__ ("rdtsc" : "=a" (res[0]), "=d" (res[1]) );
+ __asm__ __volatile__ (
+ "xorl %%eax, %%eax\n"
+ "cpuid\n"
+ ::: "%eax", "%ebx", "%ecx", "%edx"
+ );
+
+ return * reinterpret_cast< cycle_t * >( res);
+}
+
+struct measure
+{
+ cycle_t operator()()
+ {
+ cycle_t start( get_cycles() );
+ return get_cycles() - start;
+ }
+};
+
+inline
+cycle_t get_overhead()
+{
+ std::size_t iterations( 10);
+ std::vector< cycle_t > overhead( iterations, 0);
+ for ( std::size_t i( 0); i < iterations; ++i)
+ std::generate(
+ overhead.begin(), overhead.end(),
+ measure() );
+ BOOST_ASSERT( overhead.begin() != overhead.end() );
+ return * std::min_element( overhead.begin(), overhead.end() );
+}
+
+#endif // PERFORMANCE_GCC_I386_H

Added: trunk/libs/context/performance/performance_gcc_x86-64.hpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/performance/performance_gcc_x86-64.hpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,62 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef PERFORMANCE_GCC_X86_64_H
+#define PERFORMANCE_GCC_X86_64_H
+
+#include <algorithm>
+#include <cstddef>
+#include <vector>
+
+#include <boost/assert.hpp>
+#include <boost/bind.hpp>
+#include <boost/cstdint.hpp>
+
+typedef boost::uint64_t cycle_t;
+
+inline
+cycle_t get_cycles()
+{
+ boost::uint32_t res[2];
+
+ __asm__ __volatile__ (
+ "xorl %%eax, %%eax\n"
+ "cpuid\n"
+ ::: "%rax", "%rbx", "%rcx", "%rdx"
+ );
+ __asm__ __volatile__ ("rdtsc" : "=a" (res[0]), "=d" (res[1]) );
+ __asm__ __volatile__ (
+ "xorl %%eax, %%eax\n"
+ "cpuid\n"
+ ::: "%rax", "%rbx", "%rcx", "%rdx"
+ );
+
+ return * ( cycle_t *)res;
+}
+
+struct measure
+{
+ cycle_t operator()()
+ {
+ cycle_t start( get_cycles() );
+ return get_cycles() - start;
+ }
+};
+
+inline
+cycle_t get_overhead()
+{
+ std::size_t iterations( 10);
+ std::vector< cycle_t > overhead( iterations, 0);
+ for ( std::size_t i( 0); i < iterations; ++i)
+ std::generate(
+ overhead.begin(), overhead.end(),
+ measure() );
+ BOOST_ASSERT( overhead.begin() != overhead.end() );
+ return * std::min_element( overhead.begin(), overhead.end() );
+}
+
+#endif // PERFORMANCE_GCC_X86_64_H

Added: trunk/libs/context/performance/performance_msvc_i386.hpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/performance/performance_msvc_i386.hpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,60 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef PERFORMANCE_MSVC_I86_H
+#define PERFORMANCE_MSVC_I86_H
+
+#include <algorithm>
+#include <cstddef>
+#include <vector>
+
+#include <boost/assert.hpp>
+#include <boost/bind.hpp>
+#include <boost/cstdint.hpp>
+
+typedef boost::uint64_t cycle_t;
+
+inline
+cycle_t get_cycles()
+{
+ boost::uint32_t res[2];
+
+ __asm {
+ xor eax, eax
+ cpuid
+ rdtsc
+ mov dword ptr res[0], eax
+ mov dword ptr res[1], edx
+ xor eax, eax
+ cpuid
+ };
+
+ return * ( cycle_t *)res;
+}
+
+struct measure
+{
+ cycle_t operator()()
+ {
+ cycle_t start( get_cycles() );
+ return get_cycles() - start;
+ }
+};
+
+inline
+cycle_t get_overhead()
+{
+ std::size_t iterations( 10);
+ std::vector< cycle_t > overhead( iterations, 0);
+ for ( std::size_t i( 0); i < iterations; ++i)
+ std::generate(
+ overhead.begin(), overhead.end(),
+ measure() );
+ BOOST_ASSERT( overhead.begin() != overhead.end() );
+ return * std::min_element( overhead.begin(), overhead.end() );
+}
+
+#endif // PERFORMANCE_MSVC_X86_64_H

Added: trunk/libs/context/src/asm/fcontext_arm_aapcs_elf_gas.S
==============================================================================
--- (empty file)
+++ trunk/libs/context/src/asm/fcontext_arm_aapcs_elf_gas.S 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,141 @@
+/*
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt)
+*/
+
+/*******************************************************************
+ * *
+ * ------------------------------------------------------------- *
+ * | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | *
+ * ------------------------------------------------------------- *
+ * | 0x0 | 0x4 | 0x8 | 0xc | 0x10| 0x14| 0x18| 0x1c| 0x20| 0x24| *
+ * ------------------------------------------------------------- *
+ * | v1 | v2 | v3 | v4 | v5 | v6 | v7 | v8 | sp | lr | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 10 | | *
+ * ------------------------------------------------------------- *
+ * | 0x28| | *
+ * ------------------------------------------------------------- *
+ * | pc | | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | *
+ * ------------------------------------------------------------- *
+ * | 0x2c|0x30| 0x34| 0x38| 0x3c| 0x40| 0x44| 0x48| 0x4c| 0x50 | *
+ * ------------------------------------------------------------- *
+ * | s16 | s17 | s18 | s19 | s20 | s21 | s22 | s23 | s24 | s25 | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 21 | 22 | 23 | 24 | 25 | 26 | | *
+ * ------------------------------------------------------------- *
+ * | 0x54| 0x58| 0x5c| 0x60| 0x64| 0x68| | *
+ * ------------------------------------------------------------- *
+ * | s26 | s27 | s28 | s29 | s30 | s31 | | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 27 | 28 | | *
+ * ------------------------------------------------------------- *
+ * | 0x6c| 0x70| | *
+ * ------------------------------------------------------------- *
+ * |sbase|slimit| | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 29 | | *
+ * ------------------------------------------------------------- *
+ * | 0x74| | *
+ * ------------------------------------------------------------- *
+ * |fclnk| | *
+ * ------------------------------------------------------------- *
+ * *
+ * *****************************************************************/
+
+.text
+.globl boost_fcontext_start
+.align 2
+.type boost_fcontext_start,%function
+boost_fcontext_start:
+ stmia a1, {v1-v8,sp-lr} @ save V1-V8,SP-LR
+ str lr, [a1,#40] @ save LR as PC
+#if (defined(__VFP_FP__) && !defined(__SOFTFP__))
+ ldr a4, [a1,#44]
+ stmia a4, {s16-s31} @ save S16-S31
+#endif
+
+ ldr a1, [a2,#8] @ restore A1 as first arg
+#if (defined(__VFP_FP__) && !defined(__SOFTFP__))
+ ldr a4, [a2,#44]
+ ldmia a4, {s16-s31} @ restore S16-S31
+#endif
+
+ ldmia a2, {v1-v8,sp-pc} @ restore v1-V8,SP-PC
+.size boost_fcontext_start,.-boost_fcontext_start
+
+.text
+.globl boost_fcontext_jump
+.align 2
+.type boost_fcontext_jump,%function
+boost_fcontext_jump:
+ stmia a1, {v1-v8,sp-lr} @ save V1-V8,SP-LR
+ str lr, [a1,#40] @ save LR as PC
+#if (defined(__VFP_FP__) && !defined(__SOFTFP__))
+ ldr a4, [a1,#44]
+ stmia a4, {s16-s31} @ save S16-S31
+#endif
+
+ mov a1, a3 @ use thrid arg as return value after jump
+#if (defined(__VFP_FP__) && !defined(__SOFTFP__))
+ ldr a4, [a2,#44]
+ ldmia a4, {s16-s31} @ restore S16-S31
+#endif
+
+ ldmia a2, {v1-v8,sp-pc} @ restore v1-V8,SP-PC
+.size boost_fcontext_jump,.-boost_fcontext_jump
+
+.text
+.globl boost_fcontext_make
+.align 2
+.type boost_fcontext_make,%function
+boost_fcontext_make:
+ str a1, [a1,#0] @ save the address of the current context
+ str a2, [a1,#40] @ save address of the function supposed to be run
+ str a3, [a1,#8] @ save void pointer
+ ldr a2, [a1,#108] @ load the stack base
+
+ push {a1,lr} @ save pointer to fcontext_t
+ mov a1, a2 @ stack pointer as arg for boost_fcontext_align
+#ifdef __PIC__
+ bl boost_fcontext_align_at_PLT @ align stack
+#else
+ bl boost_fcontext_align @ align stack
+#endif
+ mov a2, a1 @ begin of aligned stack
+ pop {a1,lr} @ restore pointer to boost_fcontext_t
+
+ str a2, [a1,#32] @ save the stack base
+ ldr a2, [a1,#116] @ load the address of the next context
+ str a2, [a1,#4] @ save the address of the next context
+ adr a2, link_fcontext @ load address of link_fcontext
+ str a2, [a1,#36] @ save address of link_fcontext
+ mov a1, #0
+ bx lr
+
+link_fcontext:
+ mov a1, v1 @ load the adddress of the current context
+ mov a2, v2 @ load the adddress of the next context
+ teq a2, #0 @ test if the address of the next context is a null pointer
+
+#ifdef __PIC__
+ bne boost_fcontext_start_at_PLT @ install next context
+
+ mov a1, #0
+ bl _exit_at_PLT @ exit application
+#else
+ bne boost_fcontext_start @ install next context
+
+ mov a1, #0
+ bl _exit @ exit application
+#endif
+.size boost_fcontext_make,.-boost_fcontext_make

Added: trunk/libs/context/src/asm/fcontext_i386_ms_pe_masm.asm
==============================================================================
--- (empty file)
+++ trunk/libs/context/src/asm/fcontext_i386_ms_pe_masm.asm 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,160 @@
+
+; Copyright Oliver Kowalke 2009.
+; Distributed under the Boost Software License, Version 1.0.
+; (See accompanying file LICENSE_1_0.txt or copy at
+; http://www.boost.org/LICENSE_1_0.txt)
+
+; --------------------------------------------------------------
+; | 0 | 1 | 2 | 3 | 4 | 5 |
+; --------------------------------------------------------------
+; | 0h | 04h | 08h | 0ch | 010h | 014h |
+; --------------------------------------------------------------
+; | EDI | ESI | EBX | EBP | ESP | EIP |
+; --------------------------------------------------------------
+; --------------------------------------------------------------
+; | 6 | 7 | |
+; --------------------------------------------------------------
+; | 018h | 01ch | |
+; --------------------------------------------------------------
+; | fc_mxcsr|fc_x87_cw| |
+; --------------------------------------------------------------
+; --------------------------------------------------------------
+; | 8 | 9 | |
+; --------------------------------------------------------------
+; | 020h | 024h | |
+; --------------------------------------------------------------
+; | ss_base | ss_limit| |
+; --------------------------------------------------------------
+; --------------------------------------------------------------
+; | 10 | |
+; --------------------------------------------------------------
+; | 028h | |
+; --------------------------------------------------------------
+; | fc_link | |
+; --------------------------------------------------------------
+; --------------------------------------------------------------
+; | 12 | |
+; --------------------------------------------------------------
+; | 030h | |
+; --------------------------------------------------------------
+; |fc_strge | |
+; --------------------------------------------------------------
+
+.386
+.XMM
+.model flat, c
+_exit PROTO, value:SDWORD
+boost_fcontext_align PROTO, vp:DWORD
+boost_fcontext_seh PROTO, except:DWORD, frame:DWORD, context:DWORD, dispatch:DWORD
+boost_fcontext_start PROTO, from:DWORD, to:DWORD, vp:DWORD
+.code
+
+boost_fcontext_jump PROC EXPORT
+ mov ecx, [esp+04h] ; load address of the first fcontext_t arg
+ mov [ecx], edi ; save EDI
+ mov [ecx+04h], esi ; save ESI
+ mov [ecx+08h], ebx ; save EBX
+ mov [ecx+0ch], ebp ; save EBP
+
+ assume fs:nothing
+ mov edx, fs:[018h] ; load NT_TIB
+ assume fs:error
+ mov eax, [edx] ; load current SEH exception list
+ mov [ecx+02ch], eax ; save current exception list
+ mov eax, [edx+04h] ; load current stack base
+ mov [ecx+020h], eax ; save current stack base
+ mov eax, [edx+08h] ; load current stack limit
+ mov [ecx+024h], eax ; save current stack limit
+ mov eax, [edx+010h] ; load fiber local storage
+ mov [ecx+030h], eax ; save fiber local storage
+
+ stmxcsr [ecx+018h] ; save SSE2 control word
+ fnstcw [ecx+01ch] ; save x87 control word
+
+ lea eax, [esp+04h] ; exclude the return address
+ mov [ecx+010h], eax ; save as stack pointer
+ mov eax, [esp] ; load return address
+ mov [ecx+014h], eax ; save return address
+
+
+ mov ecx, [esp+08h] ; load address of the second fcontext_t arg
+ mov edi, [ecx] ; restore EDI
+ mov esi, [ecx+04h] ; restore ESI
+ mov ebx, [ecx+08h] ; restore EBX
+ mov ebp, [ecx+0ch] ; restore EBP
+
+ assume fs:nothing
+ mov edx, fs:[018h] ; load NT_TIB
+ assume fs:error
+ mov eax, [ecx+02ch] ; load SEH exception list
+ mov [edx], eax ; restore next SEH item
+ mov eax, [ecx+020h] ; load stack base
+ mov [edx+04h], eax ; restore stack base
+ mov eax, [ecx+024h] ; load stack limit
+ mov [edx+08h], eax ; restore stack limit
+ mov eax, [ecx+030h] ; load fiber local storage
+ mov [edx+010h], eax ; restore fiber local storage
+
+ ldmxcsr [ecx+018h] ; restore SSE2 control word
+ fldcw [ecx+01ch] ; restore x87 control word
+
+ mov eax, [esp+0ch] ; use third arg as return value after jump
+
+ mov esp, [ecx+010h] ; restore ESP
+ mov ecx, [ecx+014h] ; fetch the address to return to
+
+ jmp ecx ; indirect jump to context
+boost_fcontext_jump ENDP
+
+boost_fcontext_make PROC EXPORT
+ mov eax, [esp+04h] ; load address of the fcontext_t arg0
+ mov [eax], eax ; save the address of current context
+ mov ecx, [esp+08h] ; load the address of the function supposed to run
+ mov [eax+014h], ecx ; save the address of the function supposed to run
+ mov edx, [eax+020h] ; load the stack base
+
+ push eax ; save pointer to fcontext_t
+ push edx ; stack pointer as arg for boost_fcontext_align
+ call boost_fcontext_align ; align stack
+ mov edx, eax ; begin of aligned stack
+ pop eax ; remove arg for boost_fcontext_align
+ pop eax ; restore pointer to fcontext_t
+
+ lea edx, [edx-014h] ; reserve space for last frame on stack, (ESP + 4) % 16 == 0
+ mov [eax+010h], edx ; save the address
+
+ mov ecx, boost_fcontext_seh ; set ECX to exception-handler
+ mov [edx+0ch], ecx ; save ECX as SEH handler
+ mov ecx, 0ffffffffh ; set ECX to -1
+ mov [edx+08h], ecx ; save ECX as next SEH item
+ lea ecx, [edx+08h] ; load address of next SEH item
+ mov [eax+02ch], ecx ; save next SEH
+
+ mov ecx, [eax+028h] ; load the address of the next context
+ mov [eax+04h], ecx ; save the address of the next context
+ mov ecx, [esp+0ch] ; load the address of the void pointer arg2
+ mov [edx+04h], ecx ; save the address of the void pointer onto the context stack
+ stmxcsr [eax+018h] ; save SSE2 control word
+ fnstcw [eax+01ch] ; save x87 control word
+ mov ecx, boost_fcontext_link ; load helper code executed after fn() returns
+ mov [edx], ecx ; save helper code executed adter fn() returns
+ xor eax, eax ; set EAX to zero
+ ret
+boost_fcontext_make ENDP
+
+boost_fcontext_link PROC
+ lea esp, [esp-0ch] ; adjust the stack to proper boundaries
+ test esi, esi ; test if a next context was given
+ je finish ; jump to finish
+
+ push esi ; push the address of the next context on the stack
+ push edi ; push the address of the current context on the stack
+ call boost_fcontext_start ; install next context
+
+finish:
+ xor eax, eax ; set EAX to zero
+ push eax ; exit code is zero
+ call _exit ; exit application
+ hlt
+boost_fcontext_link ENDP
+END

Added: trunk/libs/context/src/asm/fcontext_i386_sysv_elf_gas.S
==============================================================================
--- (empty file)
+++ trunk/libs/context/src/asm/fcontext_i386_sysv_elf_gas.S 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,154 @@
+/*
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt)
+*/
+
+/********************************************************************
+ * *
+ * -------------------------------------------------------------- *
+ * | 0 | 1 | 2 | 3 | 4 | 5 | *
+ * -------------------------------------------------------------- *
+ * | 0x0 | 0x4 | 0x8 | 0xc | 0x10 | 0x14 | *
+ * -------------------------------------------------------------- *
+ * | EDI | ESI | EBX | EBP | ESP | EIP | *
+ * -------------------------------------------------------------- *
+ * -------------------------------------------------------------- *
+ * | 6 | 7 | | *
+ * -------------------i------------------------------------------ *
+ * | 0x18 | 0x1c | | *
+ * -------------------------------------------------------------- *
+ * | fc_mxcsr|fc_x87_cw| | *
+ * -------------------------------------------------------------- *
+ * -------------------------------------------------------------- *
+ * | 8 | 9 | | *
+ * -------------------------------------------------------------- *
+ * | 0x20 | 0x24 | | *
+ * -------------------------------------------------------------- *
+ * | sbase | slimit | | *
+ * -------------------------------------------------------------- *
+ * -------------------------------------------------------------- *
+ * | 10 | | *
+ * -------------------------------------------------------------- *
+ * | 0x28 | | *
+ * -------------------------------------------------------------- *
+ * | fc_link | | *
+ * -------------------------------------------------------------- *
+ * *
+ * *****************************************************************/
+
+.text
+.globl boost_fcontext_jump
+.align 2
+.type boost_fcontext_jump,@function
+boost_fcontext_jump:
+ movl 0x4(%esp), %ecx /* load address of the first fcontext_t arg */
+ movl %edi, (%ecx) /* save EDI */
+ movl %esi, 0x4(%ecx) /* save ESI */
+ movl %ebx, 0x8(%ecx) /* save EBX */
+ movl %ebp, 0xc(%ecx) /* save EBP */
+
+ stmxcsr 0x18(%ecx) /* save SSE2 control and status word */
+ fnstcw 0x1c(%ecx) /* save x87 control word */
+
+ leal 0x4(%esp), %eax /* exclude the return address */
+ movl %eax, 0x10(%ecx) /* save as stack pointer */
+ movl (%esp), %eax /* load return address */
+ movl %eax, 0x14(%ecx) /* save return address */
+
+
+ movl 0x8(%esp), %ecx /* load address of the second fcontext_t arg */
+ movl (%ecx), %edi /* restore EDI */
+ movl 0x4(%ecx), %esi /* restore ESI */
+ movl 0x8(%ecx), %ebx /* restore EBX */
+ movl 0xc(%ecx), %ebp /* restore EBP */
+
+ ldmxcsr 0x18(%ecx) /* restore SSE2 control and status word */
+ fldcw 0x1c(%ecx) /* restore x87 control word */
+
+ movl 0xc(%esp), %eax /* use third arg as return value after jump */
+
+ movl 0x10(%ecx), %esp /* restore ESP */
+ movl 0x14(%ecx), %ecx /* fetch the address to return to */
+
+ jmp *%ecx /* indirect jump to context */
+.size boost_fcontext_jump,.-boost_fcontext_jump
+
+.text
+.globl boost_fcontext_make
+.align 2
+.type boost_fcontext_make,@function
+boost_fcontext_make:
+ movl 0x4(%esp), %eax /* load address of the fcontext_t */
+ movl %eax, (%eax) /* save the address of current context */
+ movl 0x8(%esp), %ecx /* load the address of the function supposed to run */
+ movl %ecx, 0x14(%eax) /* save the address of the function supposed to run */
+ movl 0x20(%eax), %edx /* load the stack base */
+
+ pushl %eax /* save pointer to fcontext_t */
+ pushl %ebx /* save EBX */
+ pushl %edx /* stack pointer as arg for boost_fcontext_align */
+#ifdef __PIC__
+ call 1f
+1: popl %ebx /* address of label 1 */
+ addl $_GLOBAL_OFFSET_TABLE_+[.-1b], %ebx /* compute address of GOT and store it in EBX */
+ call boost_fcontext_align_at_PLT /* align stack */
+#else
+ call boost_fcontext_align /* align stack */
+#endif
+ movl %eax, %edx /* begin of aligned stack */
+ popl %eax /* remove arg for boost_fcontext_align */
+ popl %ebx /* restore EBX */
+ popl %eax /* restore pointer to fcontext_t */
+
+ leal -0x14(%edx), %edx /* reserve space for the last frame on stack, (ESP + 4) % 16 == 0 */
+ movl %edx, 0x10(%eax) /* save the address as stack pointer */
+ movl 0x28(%eax), %ecx /* load the address of the next context */
+ movl %ecx, 0x4(%eax) /* save the address of the next context */
+ movl 0xc(%esp), %ecx /* load the address of the void pointer */
+ movl %ecx, 0x4(%edx) /* save the address of the void pointer */
+ stmxcsr 0x18(%eax) /* save SSE2 control and status word */
+ fnstcw 0x1c(%eax) /* save x87 control word */
+#ifdef __PIC__
+ call 2f
+2: popl %ecx /* address of label 1 */
+ addl $link_fcontext-2b, %ecx /* compute address of label link_fcontext */
+ movl %ecx, (%edx) /* store address of link_fcontext as return address on stack */
+#else
+ movl $link_fcontext, (%edx) /* store address of link_fcontext as return address on stack */
+#endif
+
+ xorl %eax, %eax /* set EAX to zero */
+ ret
+
+link_fcontext:
+ leal -0xc(%esp), %esp
+
+#ifdef __PIC__
+ call 3f
+3: popl %ebx /* address of label 2 */
+ addl $_GLOBAL_OFFSET_TABLE_+[.-3b], %ebx /* compute address of GOT and store it in EBX */
+#endif
+
+ testl %esi, %esi /* test if a next context was given */
+ je 4f /* jump to finish */
+
+ pushl %esi /* push the address of the next context on the stack */
+ pushl %edi /* push the address of the current context to stack */
+#ifdef __PIC__
+ call boost_fcontext_start_at_PLT /* jump to next context */
+#else
+ call boost_fcontext_start /* jump to next context */
+#endif
+
+4:
+ movl %eax, %eax
+ pushl %eax /* exit code is zero */
+#ifdef __PIC__
+ call _exit_at_PLT /* exit application */
+#else
+ call _exit /* exit application */
+#endif
+ hlt
+.size boost_fcontext_make,.-boost_fcontext_make

Added: trunk/libs/context/src/asm/fcontext_mips32_o32_elf_gas.S
==============================================================================
--- (empty file)
+++ trunk/libs/context/src/asm/fcontext_mips32_o32_elf_gas.S 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,173 @@
+/*
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt)
+*/
+
+/*******************************************************************
+ * *
+ * ------------------------------------------------------------- *
+ * | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | *
+ * ------------------------------------------------------------- *
+ * | 0 | 8 | 16 | 24 | 32 | 40 | 48 | 56 | 64 | 72 | *
+ * ------------------------------------------------------------- *
+ * | S0 | S1 | S2 | S3 | S4 | S5 | S6 | S7 | GP | SP | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 10 | 11 | 12 | | *
+ * ------------------------------------------------------------- *
+ * | 80 | 88 | 96 | | *
+ * ------------------------------------------------------------- *
+ * | S8 | RA | PC | | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 13 | 14 | 15 | 16 | 17 | 18 | | *
+ * ------------------------------------------------------------- *
+ * | 104 | 112 | 120 | 128 | 136 | 144 | | *
+ * ------------------------------------------------------------- *
+ * | F20 | F22 | F24 | F26 | F28 | F30 | | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 19 | 20 | | *
+ * ------------------------------------------------------------- *
+ * | 152 | 156 | | *
+ * ------------------------------------------------------------- *
+ * |sbase|slimt| | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 21 | | *
+ * ------------------------------------------------------------- *
+ * | 160 | | *
+ * ------------------------------------------------------------- *
+ * |flink| | *
+ * ------------------------------------------------------------- *
+ * *
+ * *****************************************************************/
+
+.text
+.globl boost_fcontext_jump
+.align 2
+.type boost_fcontext_jump,@function
+.ent boost_fcontext_jump
+boost_fcontext_jump:
+ sw $s0, ($a0) # save S0
+ sw $s1, 8($a0) # save S1
+ sw $s2, 16($a0) # save S2
+ sw $s3, 24($a0) # save S3
+ sw $s4, 32($a0) # save S4
+ sw $s5, 40($a0) # save S5
+ sw $s6, 48($a0) # save S6
+ sw $s7, 56($a0) # save S7
+ sw $gp, 64($a0) # save GP
+ sw $sp, 72($a0) # save SP
+ sw $s8, 80($a0) # save S8
+ sw $ra, 88($a0) # save RA
+ sw $ra, 96($a0) # save RA as PC
+
+#if defined(__mips_hard_float)
+ s.d $f20, 104($a0) # save F20
+ s.d $f22, 112($a0) # save F22
+ s.d $f24, 120($a0) # save F24
+ s.d $f26, 128($a0) # save F26
+ s.d $f28, 136($a0) # save F28
+ s.d $f30, 144($a0) # save F30
+#endif
+
+
+ lw $s0, ($a1) # restore S0
+ lw $s1, 8($a1) # restore S1
+ lw $s2, 16($a1) # restore S2
+ lw $s3, 24($a1) # restore S3
+ lw $s4, 32($a1) # restore S4
+ lw $s5, 40($a1) # restore S5
+ lw $s6, 48($a1) # restore S6
+ lw $s7, 56($a1) # restore S7
+ lw $gp, 64($a1) # restore GP
+ lw $sp, 72($a1) # restore SP
+ lw $s8, 80($a1) # restore S8
+ lw $ra, 88($a1) # restore RA
+ move $a0, $s2 # restore void pointer as argument
+
+#if defined(__mips_hard_float)
+ l.d $f20, 104($a1) # restore F20
+ l.d $f22, 112($a1) # restore F22
+ l.d $f24, 120($a1) # restore F24
+ l.d $f26, 128($a1) # restore F26
+ l.d $f28, 136($a1) # restore F28
+ l.d $f30, 144($a1) # restore F30
+#endif
+
+ move $v0, $a2 # use third arg as return value after jump
+
+ lw $t9, 96($a1) # load PC
+ jr $t9 # jump to context
+.end boost_fcontext_jump
+.size boost_fcontext_jump, .-boost_fcontext_jump
+
+.text
+.globl boost_fcontext_make
+.align 2
+.type boost_fcontext_make,@function
+.ent boost_fcontext_make
+boost_fcontext_make:
+#ifdef __PIC__
+.set noreorder
+.cpload $t9
+.set reorder
+#endif
+ sw $a0, ($a0) # save the current context
+ sw $gp, 24($a0) # save global pointer
+ sw $a1, 96($a0) # save the address of the function supposed to be run
+ sw $a2, 16($a0) # save void pointer
+ lw $t0, 152($a0) # load the stack base
+
+ sub $sp, $sp, 28
+ sw $ra, 24($sp)
+ sw $a0, 20($sp)
+ move $a0, $t0 # stack pointer as arg for boost_fcontext_align
+#ifdef __PIC__
+ lw $t9, %call16(boost_fcontext_align)($gp) # align stack
+ jalr $t9
+#else
+ jal boost_fcontext_align # align stack
+#endif
+ nop
+ move $t0, $v0 # begin of aligned stack
+ lw $ra, 24($sp)
+ lw $a0, 20($sp)
+ addi $sp, $sp, 28
+
+ sub $t0, $t0, 16 # reserve 16 byte of argument space
+ sw $t0, 72($a0) # save the stack base
+ lw $t0, 160($a0) # load address of next user context
+ sw $t0, 8($a0) # save the next context
+ la $t9, link_fcontext # get address of link_fcontext
+ sw $t9, 88($a0) # save address of link_fcontext
+
+ move $v0, $zero
+ jr $ra
+
+link_fcontext:
+ move $gp, $s3 # restore GP (global pointer)
+ move $a1, $s1 # set A1 to address of next context
+ beqz $a1, 2f # test if a next context was given
+
+ move $a0, $s0 # set A0 to address of current context
+#ifdef __PIC__
+ lw $t9, %call16(boost_fcontext_start)($gp) # install next context
+ jr $t9
+#else
+ j boost_fcontext_start # install next context
+#endif
+
+2:
+ move $a0, $zero
+#ifdef __PIC__
+ lw $t9, %call16(_exit)($gp) # exit application
+ jalr $t9
+#else
+ j _exit # exit application
+#endif
+.end boost_fcontext_make
+.size boost_fcontext_make, .-boost_fcontext_make

Added: trunk/libs/context/src/asm/fcontext_ppc32_sysv_elf_gas.S
==============================================================================
--- (empty file)
+++ trunk/libs/context/src/asm/fcontext_ppc32_sysv_elf_gas.S 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,363 @@
+/*
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt)
+*/
+
+/*******************************************************************
+ * *
+ * ------------------------------------------------------------- *
+ * | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | *
+ * ------------------------------------------------------------- *
+ * | 0 | 4 | 8 | 12 | 16 | 20 | 24 | 28 | 32 | 36 | *
+ * ------------------------------------------------------------- *
+ * | R13 | R14 | R15 | R16 | R17 | R18 | R19 | R20 | R21 | R22 | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | *
+ * ------------------------------------------------------------- *
+ * | 40 | 44 | 48 | 52 | 56 | 60 | 64 | 68 | 72 | 76 | *
+ * ------------------------------------------------------------- *
+ * | R23 | R24 | R25 | R26 | R27 | R28 | R29 | R30 | R31 | SP | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 20 | 21 | 22 | 23 | | *
+ * ------------------------------------------------------------- *
+ * | 80 | 84 | 88 | 92 | | *
+ * ------------------------------------------------------------- *
+ * | CR | LR | PC | | | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | *
+ * ------------------------------------------------------------- *
+ * | 96 | 100 | 104 | 108 | 112 | 116 | 120 | 124 | 128 | 132 | *
+ * ------------------------------------------------------------- *
+ * | F14 | F15 | F16 | F17 | F18 | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | *
+ * ------------------------------------------------------------- *
+ * | 136 | 140 | 144 | 148 | 152 | 156 | 160 | 164 | 168 | 172 | *
+ * ------------------------------------------------------------- *
+ * | F19 | F20 | F21 | F22 | F23 | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | *
+ * ------------------------------------------------------------- *
+ * | 176 | 180 | 184 | 188 | 192 | 196 | 200 | 204 | 208 | 212 | *
+ * ------------------------------------------------------------- *
+ * | F24 | F25 | F26 | F27 | F28 | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | | *
+ * ------------------------------------------------------------- *
+ * | 216 | 220 | 224 | 228 | 232 | 236 | 240 | 244 | | *
+ * ------------------------------------------------------------- *
+ * | F29 | F30 | F31 | fpscr | | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 62 | 63 | | *
+ * ------------------------------------------------------------- *
+ * | 248 | 252 | | *
+ * ------------------------------------------------------------- *
+ * |sbase|slimt| | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+<<<<<<< HEAD
+ * | 63 | | *
+=======
+ * | 64 | | *
+>>>>>>> desc of fcontext_t layout for PPC modified
+ * ------------------------------------------------------------- *
+ * | 256 | | *
+ * ------------------------------------------------------------- *
+ * |flink| | *
+ * ------------------------------------------------------------- *
+ * *
+ * *****************************************************************/
+
+.text
+.globl boost_fcontext_start
+.align 2
+.type boost_fcontext_start,@function
+boost_fcontext_start:
+ stw %r13, 0(%r3) # save R13
+ stw %r14, 4(%r3) # save R14
+ stw %r15, 8(%r3) # save R15
+ stw %r16, 12(%r3) # save R16
+ stw %r17, 16(%r3) # save R17
+ stw %r18, 20(%r3) # save R18
+ stw %r19, 24(%r3) # save R19
+ stw %r20, 28(%r3) # save R20
+ stw %r21, 32(%r3) # save R21
+ stw %r22, 36(%r3) # save R22
+ stw %r23, 40(%r3) # save R23
+ stw %r24, 44(%r3) # save R24
+ stw %r25, 48(%r3) # save R25
+ stw %r26, 52(%r3) # save R26
+ stw %r27, 56(%r3) # save R27
+ stw %r28, 60(%r3) # save R28
+ stw %r29, 64(%r3) # save R29
+ stw %r30, 68(%r3) # save R30
+ stw %r31, 72(%r3) # save R31
+ stw %r1, 76(%r3) # save SP
+
+ mfcr %r0 # load CR
+ stw %r0, 80(%r3) # save CR
+ mflr %r0 # load LR
+ stw %r0, 84(%r3) # save LR
+ stw %r0, 88(%r3) # save LR as PC
+
+ stfd %f14, 96(%r3) # save F14
+ stfd %f15, 104(%r3) # save F15
+ stfd %f16, 112(%r3) # save F16
+ stfd %f17, 120(%r3) # save F17
+ stfd %f18, 128(%r3) # save F18
+ stfd %f19, 136(%r3) # save F19
+ stfd %f20, 144(%r3) # save F20
+ stfd %f21, 152(%r3) # save F21
+ stfd %f22, 160(%r3) # save F22
+ stfd %f23, 168(%r3) # save F23
+ stfd %f24, 176(%r3) # save F24
+ stfd %f25, 184(%r3) # save F25
+ stfd %f26, 192(%r3) # save F26
+ stfd %f27, 200(%r3) # save F27
+ stfd %f28, 208(%r3) # save F28
+ stfd %f29, 216(%r3) # save F29
+ stfd %f30, 224(%r3) # save F30
+ stfd %f31, 232(%r3) # save F31
+ mffs %f0 # load FPSCR
+ stfd %f0, 240(%r3) # save FPSCR
+
+
+ lwz %r13, 0(%r4) # restore R13
+ lwz %r14, 4(%r4) # restore R14
+ lwz %r15, 8(%r4) # restore R15
+ lwz %r16, 12(%r4) # restore R16
+ lwz %r17, 16(%r4) # restore R17
+ lwz %r18, 20(%r4) # restore R18
+ lwz %r19, 24(%r4) # restore R19
+ lwz %r20, 28(%r4) # restore R20
+ lwz %r21, 32(%r4) # restore R21
+ lwz %r22, 36(%r4) # restore R22
+ lwz %r23, 40(%r4) # restore R23
+ lwz %r24, 44(%r4) # restore R24
+ lwz %r25, 48(%r4) # restore R25
+ lwz %r26, 52(%r4) # restore R26
+ lwz %r27, 56(%r4) # restore R27
+ lwz %r28, 60(%r4) # restore R28
+ lwz %r29, 64(%r4) # restore R29
+ lwz %r30, 68(%r4) # restore R30
+ lwz %r31, 72(%r4) # restore R31
+ lwz %r1, 76(%r4) # restore SP
+
+ lwz %r0, 80(%r4) # load CR
+ mtcr %r0 # restore CR
+ lwz %r0, 84(%r4) # load LR
+ mtlr %r0 # restore LR
+
+ lfd %f14, 96(%r4) # restore F14
+ lfd %f15, 104(%r4) # restore F15
+ lfd %f16, 112(%r4) # restore F16
+ lfd %f17, 120(%r4) # restore F17
+ lfd %f18, 128(%r4) # restore F18
+ lfd %f19, 136(%r4) # restore F19
+ lfd %f20, 144(%r4) # restore F20
+ lfd %f21, 152(%r4) # restore F21
+ lfd %f22, 160(%r4) # restore F22
+ lfd %f23, 168(%r4) # restore F23
+ lfd %f24, 176(%r4) # restore F24
+ lfd %f25, 184(%r4) # restore F25
+ lfd %f26, 192(%r4) # restore F26
+ lfd %f27, 200(%r4) # restore F27
+ lfd %f28, 208(%r4) # restore F28
+ lfd %f29, 216(%r4) # restore F29
+ lfd %f30, 224(%r4) # restore F30
+ lfd %f31, 232(%r4) # restore F31
+ lfd %f0, 240(%r4) # load FPSCR
+ mtfsf 0xff, %f0 # restore FPSCR
+
+ lwz %r0, 88(%r4) # load PC
+ mr. %r3, %r15 # load void pointer as argument
+ mtctr %r0 # restore CTR
+
+ bctr # start to context
+.size boost_fcontext_start, .-boost_fcontext_start
+
+.text
+.globl boost_fcontext_jump
+.align 2
+.type boost_fcontext_jump,@function
+boost_fcontext_jump:
+ stw %r13, 0(%r3) # save R13
+ stw %r14, 4(%r3) # save R14
+ stw %r15, 8(%r3) # save R15
+ stw %r16, 12(%r3) # save R16
+ stw %r17, 16(%r3) # save R17
+ stw %r18, 20(%r3) # save R18
+ stw %r19, 24(%r3) # save R19
+ stw %r20, 28(%r3) # save R20
+ stw %r21, 32(%r3) # save R21
+ stw %r22, 36(%r3) # save R22
+ stw %r23, 40(%r3) # save R23
+ stw %r24, 44(%r3) # save R24
+ stw %r25, 48(%r3) # save R25
+ stw %r26, 52(%r3) # save R26
+ stw %r27, 56(%r3) # save R27
+ stw %r28, 60(%r3) # save R28
+ stw %r29, 64(%r3) # save R29
+ stw %r30, 68(%r3) # save R30
+ stw %r31, 72(%r3) # save R31
+ stw %r1, 76(%r3) # save SP
+
+ mfcr %r0 # load CR
+ stw %r0, 80(%r3) # save CR
+ mflr %r0 # load LR
+ stw %r0, 84(%r3) # save LR
+ stw %r0, 88(%r3) # save LR as PC
+
+ stfd %f14, 92(%r3) # save F14
+ stfd %f15, 100(%r3) # save F15
+ stfd %f16, 108(%r3) # save F16
+ stfd %f17, 116(%r3) # save F17
+ stfd %f18, 124(%r3) # save F18
+ stfd %f19, 132(%r3) # save F19
+ stfd %f20, 140(%r3) # save F20
+ stfd %f21, 148(%r3) # save F21
+ stfd %f22, 156(%r3) # save F22
+ stfd %f23, 164(%r3) # save F23
+ stfd %f24, 172(%r3) # save F24
+ stfd %f25, 180(%r3) # save F25
+ stfd %f26, 188(%r3) # save F26
+ stfd %f27, 196(%r3) # save F27
+ stfd %f28, 204(%r3) # save F28
+ stfd %f29, 212(%r3) # save F29
+ stfd %f30, 220(%r3) # save F30
+ stfd %f31, 228(%r3) # save F31
+ mffs %f0 # load FPSCR
+ stfd %f0, 236(%r3) # save FPSCR
+
+
+ lwz %r13, 0(%r4) # restore R13
+ lwz %r14, 4(%r4) # restore R14
+ lwz %r15, 8(%r4) # restore R15
+ lwz %r16, 12(%r4) # restore R16
+ lwz %r17, 16(%r4) # restore R17
+ lwz %r18, 20(%r4) # restore R18
+ lwz %r19, 24(%r4) # restore R19
+ lwz %r20, 28(%r4) # restore R20
+ lwz %r21, 32(%r4) # restore R21
+ lwz %r22, 36(%r4) # restore R22
+ lwz %r23, 40(%r4) # restore R23
+ lwz %r24, 44(%r4) # restore R24
+ lwz %r25, 48(%r4) # restore R25
+ lwz %r26, 52(%r4) # restore R26
+ lwz %r27, 56(%r4) # restore R27
+ lwz %r28, 60(%r4) # restore R28
+ lwz %r29, 64(%r4) # restore R29
+ lwz %r30, 68(%r4) # restore R30
+ lwz %r31, 72(%r4) # restore R31
+ lwz %r1, 76(%r4) # restore SP
+
+ lwz %r0, 80(%r4) # load CR
+ mtcr %r0 # restore CR
+ lwz %r0, 84(%r4) # load LR
+ mtlr %r0 # restore LR
+
+ lfd %f14, 92(%r4) # restore F14
+ lfd %f15, 100(%r4) # restore F15
+ lfd %f16, 108(%r4) # restore F16
+ lfd %f17, 116(%r4) # restore F17
+ lfd %f18, 124(%r4) # restore F18
+ lfd %f19, 132(%r4) # restore F19
+ lfd %f20, 140(%r4) # restore F20
+ lfd %f21, 148(%r4) # restore F21
+ lfd %f22, 156(%r4) # restore F22
+ lfd %f23, 164(%r4) # restore F23
+ lfd %f24, 172(%r4) # restore F24
+ lfd %f25, 180(%r4) # restore F25
+ lfd %f26, 188(%r4) # restore F26
+ lfd %f27, 196(%r4) # restore F27
+ lfd %f28, 204(%r4) # restore F28
+ lfd %f29, 212(%r4) # restore F29
+ lfd %f30, 220(%r4) # restore F30
+ lfd %f31, 228(%r4) # restore F31
+ lfd %f0, 236(%r4) # load FPSCR
+ mtfsf 0xff, %f0 # restore FPSCR
+
+ mr. %r3, %r5 # use third arg as return value after jump
+
+ lwz %r0, 88(%r4) # load PC
+ mtctr %r0 # restore CTR
+
+ bctr # jump to context
+.size boost_fcontext_jump, .-boost_fcontext_jump
+
+.text
+.globl boost_fcontext_make
+.align 2
+.type boost_fcontext_make,@function
+boost_fcontext_make:
+ stw %r3, 0(%r3) # save the current context
+ stw %r4, 88(%r3) # save the address of the function supposed to to be run
+ stw %r5, 8(%r3) # save void pointer
+ lwz %r0, 248(%r3) # load the stack base
+
+ li %r4, 28
+ subf %r1, %r4, %r1 # reserve space on stack
+ stw %r3, 24(%r1) # store pointer to fcontext_t on stack
+ mflr %r4 # load LR
+ stw %r4, 20(%r1) # store LR on stack
+ mr. %r3, %r0 # context stack as arg to boost_fcontext_algin
+#ifdef __PIC__
+ bl boost_fcontext_align_at_plt # call boost_fcontext_align
+#else
+ bl boost_fcontext_align # call boost_fcontext_align
+#endif
+ mr. %r0, %r3 # load result into R0
+ lwz %r4, 20(%r1) # pop LR from stack
+ mtlr %r4 # restore LR
+ lwz %r3, 24(%r1) # pop pointer to fcontext_t from stack
+ addi %r1, %r1, 28 # release space on stack
+
+ li %r4, 16
+ subf %r0, %r4, %r0 # reserve 16 bytes on top of the stack
+ stw %r0, 76(%r3) # save the stack base
+ lwz %r0, 256(%r3) # load address of next user context
+ stw %r0, 4(%r3) # save the next context
+#ifdef __PIC__
+ mflr %r0 # load LR
+ bl 1f # jump to label 1
+1:
+ mflr %r4 # load LR
+ addi %r4, %r4, link_fcontext - 1b # calulate absolute address of link_fcontext
+ mtlr %r0 # restore LR
+#else
+ lis %r4, link_fcontext_at_ha # get hight address of link_fcontext
+ addi %r4, %r4, link_fcontext_at_l # get low address of link_fcontext
+#endif
+ stw %r4, 84(%r3) # save address of link_fcontext
+
+ li %r3, 0 # set return value to zero
+ blr
+
+link_fcontext:
+ mr. %r3, %r13
+ mr. %r4, %r14
+ beq 2f # test if a next context was given
+
+#ifdef __PIC__
+ bl boost_fcontext_start_at_plt # install next context
+
+2:
+ li %r3, 0 # set return value to zero
+ bl _exit_at_plt # exit application
+#else
+ bl boost_fcontext_start # install next context
+
+2:
+ li %r3, 0 # set return value to zero
+ bl _exit # exit application
+#endif
+.size boost_fcontext_make, .-boost_fcontext_make

Added: trunk/libs/context/src/asm/fcontext_ppc64_sysv_elf_gas.S
==============================================================================
--- (empty file)
+++ trunk/libs/context/src/asm/fcontext_ppc64_sysv_elf_gas.S 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,373 @@
+/*
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt)
+*/
+
+/*******************************************************************
+ * *
+ * ------------------------------------------------------------- *
+ * | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | *
+ * ------------------------------------------------------------- *
+ * | 0 | 4 | 8 | 12 | 16 | 20 | 24 | 28 | 32 | 36 | *
+ * ------------------------------------------------------------- *
+ * | R13 | R14 | R15 | R16 | R17 | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | *
+ * ------------------------------------------------------------- *
+ * | 40 | 44 | 48 | 52 | 56 | 60 | 64 | 68 | 72 | 76 | *
+ * ------------------------------------------------------------- *
+ * | R18 | R19 | R20 | R21 | R22 | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | *
+ * ------------------------------------------------------------- *
+ * | 80 | 84 | 88 | 92 | 96 | 100 | 104 | 108 | 112 | 116 | *
+ * ------------------------------------------------------------- *
+ * | R23 | R24 | R25 | R26 | R27 | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | *
+ * ------------------------------------------------------------- *
+ * | 120 | 124 | 128 | 132 | 136 | 140 | 144 | 148 | 152 | 156 | *
+ * ------------------------------------------------------------- *
+ * | R28 | R29 | R30 | R31 | SP | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 40 | 41 | 42 | 43 | 44 | 45 | | *
+ * ------------------------------------------------------------- *
+ * | 160 | 164 | 168 | 172 | 176 | 180 | | *
+ * ------------------------------------------------------------- *
+ * | CR | LR | PC | | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | *
+ * ------------------------------------------------------------- *
+ * | 192 | 196 | 200 | 204 | 208 | 212 | 216 | 220 | 224 | 228 | *
+ * ------------------------------------------------------------- *
+ * | F14 | F15 | F16 | F17 | F18 | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | *
+ * ------------------------------------------------------------- *
+ * | 232 | 236 | 240 | 244 | 248 | 252 | 256 | 260 | 264 | 268 | *
+ * ------------------------------------------------------------- *
+ * | F19 | F20 | F21 | F22 | F23 | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | *
+ * ------------------------------------------------------------- *
+ * | 272 | 276 | 280 | 284 | 288 | 292 | 296 | 300 | 304 | 308 | *
+ * ------------------------------------------------------------- *
+ * | F24 | F25 | F26 | F27 | F28 | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 78 | 79 | 80 | 81 | 82 | 83 | 84 | 85 | | *
+ * ------------------------------------------------------------- *
+ * | 312 | 316 | 320 | 324 | 328 | 332 | 336 | 340 | | *
+ * ------------------------------------------------------------- *
+ * | F29 | F30 | F31 | fpscr | | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 86 | 87 | 88 | 89 | | *
+ * ------------------------------------------------------------- *
+ * | 344 | 348 | 352 | 356 | | *
+ * ------------------------------------------------------------- *
+ * | sbase | slimt | | *
+ * ------------------------------------------------------------- *
+ * ------------------------------------------------------------- *
+ * | 90 | 91 | | *
+ * ------------------------------------------------------------- *
+ * | 360 | 364 | | *
+ * ------------------------------------------------------------- *
+ * | flink | | *
+ * ------------------------------------------------------------- *
+ * *
+ * *****************************************************************/
+
+.text
+.globl boost_fcontext_start
+.align 2
+.type boost_fcontext_start,@function
+boost_fcontext_start:
+ std %r13, 0(%r3) # save R13
+ std %r14, 8(%r3) # save R14
+ std %r15, 16(%r3) # save R15
+ std %r16, 24(%r3) # save R16
+ std %r17, 32(%r3) # save R17
+ std %r18, 40(%r3) # save R18
+ std %r19, 48(%r3) # save R19
+ std %r20, 56(%r3) # save R20
+ std %r21, 64(%r3) # save R21
+ std %r22, 72(%r3) # save R22
+ std %r23, 80(%r3) # save R23
+ std %r24, 88(%r3) # save R24
+ std %r25, 96(%r3) # save R25
+ std %r26, 104(%r3) # save R26
+ std %r27, 112(%r3) # save R27
+ std %r28, 120(%r3) # save R28
+ std %r29, 128(%r3) # save R29
+ std %r30, 136(%r3) # save R30
+ std %r31, 144(%r3) # save R31
+ std %r1, 152(%r3) # save SP
+
+ mfcr %r0 # load CR
+ std %r0, 160(%r3) # save CR
+ mflr %r0 # load LR
+ std %r0, 168(%r3) # save LR
+ std %r0, 176(%r3) # save LR as PC
+
+ stfd %f14, 192(%r3) # save F14
+ stfd %f15, 200(%r3) # save F15
+ stfd %f16, 208(%r3) # save F16
+ stfd %f17, 216(%r3) # save F17
+ stfd %f18, 224(%r3) # save F18
+ stfd %f19, 232(%r3) # save F19
+ stfd %f20, 240(%r3) # save F20
+ stfd %f21, 248(%r3) # save F21
+ stfd %f22, 256(%r3) # save F22
+ stfd %f23, 264(%r3) # save F23
+ stfd %f24, 272(%r3) # save F24
+ stfd %f25, 280(%r3) # save F25
+ stfd %f26, 288(%r3) # save F26
+ stfd %f27, 296(%r3) # save F27
+ stfd %f28, 304(%r3) # save F28
+ stfd %f29, 312(%r3) # save F29
+ stfd %f30, 320(%r3) # save F30
+ stfd %f31, 328(%r3) # save F31
+ mffs %f0 # load FPSCR
+ stfd %f0, 336(%r3) # save FPSCR
+
+
+ ld %r13, 0(%r4) # restore R13
+ ld %r14, 8(%r4) # restore R14
+ ld %r15, 16(%r4) # restore R15
+ ld %r16, 24(%r4) # restore R16
+ ld %r17, 32(%r4) # restore R17
+ ld %r18, 40(%r4) # restore R18
+ ld %r19, 48(%r4) # restore R19
+ ld %r20, 56(%r4) # restore R20
+ ld %r21, 64(%r4) # restore R21
+ ld %r22, 72(%r4) # restore R22
+ ld %r23, 80(%r4) # restore R23
+ ld %r24, 88(%r4) # restore R24
+ ld %r25, 96(%r4) # restore R25
+ ld %r26, 104(%r4) # restore R26
+ ld %r27, 112(%r4) # restore R27
+ ld %r28, 120(%r4) # restore R28
+ ld %r29, 128(%r4) # restore R29
+ ld %r40, 136(%r4) # restore r40
+ ld %r41, 144(%r4) # restore r41
+ ld %r1, 152(%r4) # restore SP
+
+ ld %r0, 160(%r4) # load CR
+ mtcr %r0 # restore CR
+ ld %r0, 168(%r4) # load LR
+ mtlr %r0 # restore LR
+
+ lfd %f14, 192(%r4) # restore F14
+ lfd %f15, 200(%r4) # restore F15
+ lfd %f16, 208(%r4) # restore F16
+ lfd %f17, 216(%r4) # restore F17
+ lfd %f18, 224(%r4) # restore F18
+ lfd %f19, 232(%r4) # restore F19
+ lfd %f20, 240(%r4) # restore F20
+ lfd %f21, 248(%r4) # restore F21
+ lfd %f22, 256(%r4) # restore F22
+ lfd %f23, 264(%r4) # restore F23
+ lfd %f24, 272(%r4) # restore F24
+ lfd %f25, 280(%r4) # restore F25
+ lfd %f26, 288(%r4) # restore F26
+ lfd %f27, 296(%r4) # restore F27
+ lfd %f28, 304(%r4) # restore F28
+ lfd %f29, 312(%r4) # restore F29
+ lfd %f30, 320(%r4) # restore F30
+ lfd %f31, 328(%r4) # restore F31
+ lfd %f0, 336(%r4) # load FPSCR
+ mtfsf 0xff, %f0 # restore FPSCR
+
+ ld %r0, 176(%r4) # load PC
+ mr. %r3, %r15 # load void pointer as argument
+ mtctr %r0 # restore CTR
+
+ bctr # start to context
+.size boost_fcontext_start, .-boost_fcontext_start
+
+.text
+.globl boost_fcontext_jump
+.align 2
+.type boost_fcontext_jump,@function
+boost_fcontext_jump:
+ std %r13, 0(%r3) # save R13
+ std %r14, 8(%r3) # save R14
+ std %r15, 16(%r3) # save R15
+ std %r16, 24(%r3) # save R16
+ std %r17, 32(%r3) # save R17
+ std %r18, 40(%r3) # save R18
+ std %r19, 48(%r3) # save R19
+ std %r20, 56(%r3) # save R20
+ std %r21, 64(%r3) # save R21
+ std %r22, 72(%r3) # save R22
+ std %r23, 80(%r3) # save R23
+ std %r24, 88(%r3) # save R24
+ std %r25, 96(%r3) # save R25
+ std %r26, 104(%r3) # save R26
+ std %r27, 112(%r3) # save R27
+ std %r28, 120(%r3) # save R28
+ std %r29, 128(%r3) # save R29
+ std %r30, 136(%r3) # save R30
+ std %r31, 144(%r3) # save R31
+ std %r1, 152(%r3) # save SP
+
+ mfcr %r0 # load CR
+ std %r0, 160(%r3) # save CR
+ mflr %r0 # load LR
+ std %r0, 168(%r3) # save LR
+ std %r0, 176(%r3) # save LR as PC
+
+ stfd %f14, 192(%r3) # save F14
+ stfd %f15, 200(%r3) # save F15
+ stfd %f16, 208(%r3) # save F16
+ stfd %f17, 216(%r3) # save F17
+ stfd %f18, 224(%r3) # save F18
+ stfd %f19, 232(%r3) # save F19
+ stfd %f20, 240(%r3) # save F20
+ stfd %f21, 248(%r3) # save F21
+ stfd %f22, 256(%r3) # save F22
+ stfd %f23, 264(%r3) # save F23
+ stfd %f24, 272(%r3) # save F24
+ stfd %f25, 280(%r3) # save F25
+ stfd %f26, 288(%r3) # save F26
+ stfd %f27, 296(%r3) # save F27
+ stfd %f28, 304(%r3) # save F28
+ stfd %f29, 312(%r3) # save F29
+ stfd %f30, 320(%r3) # save F30
+ stfd %f31, 328(%r3) # save F31
+ mffs %f0 # load FPSCR
+ stfd %f0, 336(%r3) # save FPSCR
+
+
+ ld %r13, 0(%r4) # restore R13
+ ld %r14, 8(%r4) # restore R14
+ ld %r15, 16(%r4) # restore R15
+ ld %r16, 24(%r4) # restore R16
+ ld %r17, 32(%r4) # restore R17
+ ld %r18, 40(%r4) # restore R18
+ ld %r19, 48(%r4) # restore R19
+ ld %r20, 56(%r4) # restore R20
+ ld %r21, 64(%r4) # restore R21
+ ld %r22, 72(%r4) # restore R22
+ ld %r23, 80(%r4) # restore R23
+ ld %r24, 88(%r4) # restore R24
+ ld %r25, 96(%r4) # restore R25
+ ld %r26, 104(%r4) # restore R26
+ ld %r27, 112(%r4) # restore R27
+ ld %r28, 120(%r4) # restore R28
+ ld %r29, 128(%r4) # restore R29
+ ld %r40, 136(%r4) # restore r40
+ ld %r41, 144(%r4) # restore r41
+ ld %r1, 152(%r4) # restore SP
+
+ ld %r0, 160(%r4) # load CR
+ mtcr %r0 # restore CR
+ ld %r0, 168(%r4) # load LR
+ mtlr %r0 # restore LR
+
+ lfd %f14, 192(%r4) # restore F14
+ lfd %f15, 200(%r4) # restore F15
+ lfd %f16, 208(%r4) # restore F16
+ lfd %f17, 216(%r4) # restore F17
+ lfd %f18, 224(%r4) # restore F18
+ lfd %f19, 232(%r4) # restore F19
+ lfd %f20, 240(%r4) # restore F20
+ lfd %f21, 248(%r4) # restore F21
+ lfd %f22, 256(%r4) # restore F22
+ lfd %f23, 264(%r4) # restore F23
+ lfd %f24, 272(%r4) # restore F24
+ lfd %f25, 280(%r4) # restore F25
+ lfd %f26, 288(%r4) # restore F26
+ lfd %f27, 296(%r4) # restore F27
+ lfd %f28, 304(%r4) # restore F28
+ lfd %f29, 312(%r4) # restore F29
+ lfd %f30, 320(%r4) # restore F30
+ lfd %f31, 328(%r4) # restore F31
+ lfd %f0, 336(%r4) # load FPSCR
+ mtfsf 0xff, %f0 # restore FPSCR
+
+ mr. %r3, %r5 # use third arg as return value after jump
+
+ ld %r0, 176(%r4) # load PC
+ mtctr %r0 # restore CTR
+
+ bctr # jump to context
+.size boost_fcontext_jump, .-boost_fcontext_jump
+
+.text
+.globl boost_fcontext_make
+.align 2
+.type boost_fcontext_make,@function
+boost_fcontext_make:
+ std %r3, 0(%r3) # save the current context
+ std %r4, 176(%r3) # save the address of the function supposed to be run
+ std %r5, 16(%r3) # save void pointer
+ ld %r0, 344(%r3) # load the stack base
+
+ li %r4, 56
+ subf %r1, %r4, %r1 # reserve space on stack
+ stw %r3, 48(%r1) # store pointer to fcontext_t on stack
+ mflr %r4 # load LR
+ stw %r4, 40(%r1) # store LR on stack
+ mr. %r3, %r0 # context stack as arg to boost_fcontext_algin
+#ifdef __PIC__
+ bl boost_fcontext_align_at_plt # call boost_fcontext_align
+#else
+ bl boost_fcontext_align # call boost_fcontext_align
+#endif
+ mr. %r0, %r3 # load result into R0
+ lwz %r4, 40(%r1) # pop LR from stack
+ mtlr %r4 # restore LR
+ lwz %r3, 48(%r1) # pop pointer to fcontext_t from stack
+ addi %r1, %r1, 56 # release space on stack
+
+ li %r4, 32
+ subf %r0, %r4, %r0 # reserve 32 bytes on top of the stack
+ std %r0, 152(%r3) # save the stack base
+ ld %r0, 360(%r3) # load address of next user context
+ std %r0, 8(%r3) # save the next context
+#ifdef __PIC__
+ mflr %r0 # load LR
+ bl 1f # jump to label 1
+1:
+ mflr %r4 # load LR
+ addi %r4, %r4, link_fcontext - 1b # calulate absolute address of link_fcontext
+ mtlr %r0 # restore LR
+#else
+ lis %r4, link_fcontext_at_ha # get hight address of link_fcontext
+ addi %r4, %r4, link_fcontext_at_l # get low address of link_fcontext
+#endif
+ std %r4, 168(%r3) # save address of link_fcontext
+
+ li %r3, 0 # set return value to zero
+ blr
+
+link_fcontext:
+ mr. %r3, %r13
+ mr. %r4, %r14
+ beq 2f # test if a next context was given
+
+#ifdef __PIC__
+ bl boost_fcontext_start_at_plt # install next context
+
+2:
+ li %r3, 0 # set return value to zero
+ bl _exit_at_plt # exit application
+#else
+ bl boost_fcontext_start # install next context
+
+2:
+ li %r3, 0 # set return value to zero
+ bl _exit # exit application
+#endif
+.size boost_fcontext_make, .-boost_fcontext_make

Added: trunk/libs/context/src/asm/fcontext_x86_64_ms_pe_masm.asm
==============================================================================
--- (empty file)
+++ trunk/libs/context/src/asm/fcontext_x86_64_ms_pe_masm.asm 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,172 @@
+
+; Copyright Oliver Kowalke 2009.
+; Distributed under the Boost Software License, Version 1.0.
+; (See accompanying file LICENSE_1_0.txt or copy at
+; http://www.boost.org/LICENSE_1_0.txt)
+
+; ----------------------------------------------------------------------------------
+; | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
+; ----------------------------------------------------------------------------------
+; | 0x0 | 0x4 | 0x8 | 0xc | 0x10 | 0x14 | 0x18 | 0x1c |
+; ----------------------------------------------------------------------------------
+; | R12 | R13 | R14 | R15 |
+; ----------------------------------------------------------------------------------
+; ----------------------------------------------------------------------------------
+; | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 |
+; ----------------------------------------------------------------------------------
+; | 0x20 | 0x24 | 0x28 | 0x2c | 0x30 | 0x34 | 0x38 | 0x3c |
+; ----------------------------------------------------------------------------------
+; | RDI | RSI | RBX | RBP |
+; ----------------------------------------------------------------------------------
+; ----------------------------------------------------------------------------------
+; | 16 | 17 | 18 | 19 | |
+; ----------------------------------------------------------------------------------
+; | 0x40 | 0x44 | 0x48 | 0x4c | |
+; ----------------------------------------------------------------------------------
+; | RSP | RIP | |
+; ----------------------------------------------------------------------------------
+; ----------------------------------------------------------------------------------
+; | 20 | 21 | |
+; ----------------------------------------------------------------------------------
+; | 0x50 | 0x54 | |
+; ----------------------------------------------------------------------------------
+; | fc_mxcsr|fc_x87_cw| |
+; ----------------------------------------------------------------------------------
+; ----------------------------------------------------------------------------------
+; | 22 | 23 | 24 | 25 | |
+; ----------------------------------------------------------------------------------
+; | 0x58 | 0x5c | 0x60 | 0x64 | |
+; ----------------------------------------------------------------------------------
+; | sbase | slimit | |
+; ----------------------------------------------------------------------------------
+; ----------------------------------------------------------------------------------
+; | 26 | 27 | |
+; ----------------------------------------------------------------------------------
+; | 0x68 | 0x6c | |
+; ----------------------------------------------------------------------------------
+; | fc_link | |
+; ----------------------------------------------------------------------------------
+; ----------------------------------------------------------------------------------
+; | 28 | 29 | |
+; ----------------------------------------------------------------------------------
+; | 0x70 | 0x74 | |
+; ----------------------------------------------------------------------------------
+; | fbr_strg | |
+; ----------------------------------------------------------------------------------
+
+EXTERN _exit:PROC ; standard C library function
+EXTERN boost_fcontext_align:PROC ; stack alignment
+EXTERN boost_fcontext_seh:PROC ; exception handler
+EXTERN boost_fcontext_start:PROC ; start fcontext
+.code
+
+boost_fcontext_jump PROC EXPORT FRAME:boost_fcontext_seh
+ .endprolog
+
+ mov [rcx], r12 ; save R12
+ mov [rcx+08h], r13 ; save R13
+ mov [rcx+010h], r14 ; save R14
+ mov [rcx+018h], r15 ; save R15
+ mov [rcx+020h], rdi ; save RDI
+ mov [rcx+028h], rsi ; save RSI
+ mov [rcx+030h], rbx ; save RBX
+ mov [rcx+038h], rbp ; save RBP
+
+ stmxcsr [rcx+050h] ; save SSE2 control and status word
+ fnstcw [rcx+054h] ; save x87 control word
+
+ mov r9, gs:[030h] ; load NT_TIB
+ mov rax, [r9+08h] ; load current stack base
+ mov [rcx+058h], rax ; save current stack base
+ mov rax, [r9+010h] ; load current stack limit
+ mov [rcx+060h], rax ; save current stack limit
+ mov rax, [r9+018h] ; load fiber local storage
+ mov [rcx+070h], rax ; save fiber local storage
+
+ lea rax, [rsp+08h] ; exclude the return address
+ mov [rcx+040h], rax ; save as stack pointer
+ mov rax, [rsp] ; load return address
+ mov [rcx+048h], rax ; save return address
+
+
+ mov r12, [rdx] ; restore R12
+ mov r13, [rdx+08h] ; restore R13
+ mov r14, [rdx+010h] ; restore R14
+ mov r15, [rdx+018h] ; restore R15
+ mov rdi, [rdx+020h] ; restore RDI
+ mov rsi, [rdx+028h] ; restore RSI
+ mov rbx, [rdx+030h] ; restore RBX
+ mov rbp, [rdx+038h] ; restore RBP
+
+ ldmxcsr [rdx+050h] ; restore SSE2 control and status word
+ fldcw [rdx+054h] ; restore x87 control word
+
+ mov r9, gs:[030h] ; load NT_TIB
+ mov rax, [rdx+058h] ; load stack base
+ mov [r9+08h], rax ; restore stack base
+ mov rax, [rdx+060h] ; load stack limit
+ mov [r9+010h], rax ; restore stack limit
+ mov rax, [rdx+070h] ; load fiber local storage
+ mov [r9+018h], rax ; restore fiber local storage
+
+ mov rsp, [rdx+040h] ; restore RSP
+ mov r9, [rdx+048h] ; fetch the address to returned to
+ mov rcx, r14 ; restore RCX as first argument for called context
+
+ mov rax, r8 ; use third arg as return value after jump
+
+ jmp r9 ; indirect jump to caller
+boost_fcontext_jump ENDP
+
+boost_fcontext_make PROC EXPORT FRAME ; generate function table entry in .pdata and unwind information in E
+ .endprolog ; .xdata for a function's structured exception handling unwind behavior
+
+ mov [rcx], rcx ; store the address of current context
+ mov [rcx+048h], rdx ; save the address of the function supposed to run
+ mov [rcx+010h], r8 ; save the the void pointer
+ mov rdx, [rcx+058h] ; load the address where the context stack beginns
+
+ push rcx ; save pointer to fcontext_t
+ sub rsp, 028h ; reserve shadow space for boost_fcontext_algin
+ mov rcx, rdx ; stack pointer as arg for boost_fcontext_align
+ mov [rsp+8], rcx
+ call boost_fcontext_align ; align stack
+ mov rdx, rax ; begin of aligned stack
+ add rsp, 028h
+ pop rcx ; restore pointer to fcontext_t
+
+ lea rdx, [rdx-028h] ; reserve 32byte shadow space + return address on stack, (RSP + 8) % 16 == 0
+ mov [rcx+040h], rdx ; save the address where the context stack beginns
+
+ mov rax, [rcx+068h] ; load the address of the next context
+ mov [rcx+08h], rax ; save the address of next context
+ stmxcsr [rcx+050h] ; save SSE2 control and status word
+ fnstcw [rcx+054h] ; save x87 control word
+
+ lea rax, boost_fcontext_link ; helper code executed after fn() returns
+ mov [rdx], rax ; store address off the helper function as return address
+
+ xor rax, rax ; set RAX to zero
+ ret
+boost_fcontext_make ENDP
+
+boost_fcontext_link PROC FRAME ; generate function table entry in .pdata and unwind information in
+ .endprolog ; .xdata for a function's structured exception handling unwind behavior
+
+ sub rsp, 028h ; reserve shadow space for boost_fcontext_algin
+ test r13, r13 ; test if a next context was given
+ je finish ; jump to finish
+
+ mov rcx, r12 ; first argument eq. address of current context
+ mov rdx, r13 ; second argumnet eq. address of next context
+ mov [rsp+010h], rdx
+ mov [rsp+08h], rcx
+ call boost_fcontext_start ; install next context
+
+finish:
+ xor rcx, rcx
+ mov [rsp+08h], rcx
+ call _exit ; exit application
+ hlt
+boost_fcontext_link ENDP
+END

Added: trunk/libs/context/src/asm/fcontext_x86_64_sysv_elf_gas.S
==============================================================================
--- (empty file)
+++ trunk/libs/context/src/asm/fcontext_x86_64_sysv_elf_gas.S 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,128 @@
+/*
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt)
+*/
+
+/****************************************************************************************
+ * *
+ * ---------------------------------------------------------------------------------- *
+ * | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | *
+ * ---------------------------------------------------------------------------------- *
+ * | 0x0 | 0x4 | 0x8 | 0xc | 0x10 | 0x14 | 0x18 | 0x1c | *
+ * ---------------------------------------------------------------------------------- *
+ * | RBX | R12 | R13 | R14 | *
+ * ---------------------------------------------------------------------------------- *
+ * ---------------------------------------------------------------------------------- *
+ * | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | *
+ * ---------------------------------------------------------------------------------- *
+ * | 0x20 | 0x24 | 0x28 | 0x2c | 0x30 | 0x34 | 0x38 | 0x3c | *
+ * ---------------------------------------------------------------------------------- *
+ * | R15 | RBP | RSP | RIP | *
+ * ---------------------------------------------------------------------------------- *
+ * ---------------------------------------------------------------------------------- *
+ * | 16 | 17 | | *
+ * ---------------------------------------------------------------------------------- *
+ * | 0x40 | 0x44 | | *
+ * ---------------------------------------------------------------------------------- *
+ * | fc_mxcsr|fc_x87_cw| | *
+ * ---------------------------------------------------------------------------------- *
+ * ---------------------------------------------------------------------------------- *
+ * | 18 | 19 | 20 | 21 | | *
+ * ---------------------------------------------------------------------------------- *
+ * | 0x48 | 0x4c | 0x50 | 0x54 | | *
+ * ---------------------------------------------------------------------------------- *
+ * | sbase | slimit | | *
+ * ---------------------------------------------------------------------------------- *
+ * ---------------------------------------------------------------------------------- *
+ * | 22 | 23 | | *
+ * ---------------------------------------------------------------------------------- *
+ * | 0x58 | 0x5c | | *
+ * ---------------------------------------------------------------------------------- *
+ * | fc_link | | *
+ * ---------------------------------------------------------------------------------- *
+ * *
+ * **************************************************************************************/
+
+.text
+.globl boost_fcontext_jump
+.type boost_fcontext_jump,@function
+.align 16
+boost_fcontext_jump:
+ movq %rbx, (%rdi) /* save RBX */
+ movq %r12, 0x8(%rdi) /* save R12 */
+ movq %r13, 0x10(%rdi) /* save R13 */
+ movq %r14, 0x18(%rdi) /* save R14 */
+ movq %r15, 0x20(%rdi) /* save R15 */
+ movq %rbp, 0x28(%rdi) /* save RBP */
+
+ stmxcsr 0x40(%rdi) /* save SSE2 control and status word */
+ fnstcw 0x44(%rdi) /* save x87 control word */
+
+ leaq 0x8(%rsp), %rcx /* exclude the return address and save as stack pointer */
+ movq %rcx, 0x30(%rdi) /* save as stack pointer */
+ movq (%rsp), %rcx /* save return address */
+ movq %rcx, 0x38(%rdi) /* save return address as RIP */
+
+
+ movq (%rsi), %rbx /* restore RBX */
+ movq 0x8(%rsi), %r12 /* restore R12 */
+ movq 0x10(%rsi), %r13 /* restore R13 */
+ movq 0x18(%rsi), %r14 /* restore R14 */
+ movq 0x20(%rsi), %r15 /* restore R15 */
+ movq 0x28(%rsi), %rbp /* restore RBP */
+
+ ldmxcsr 0x40(%rsi) /* restore SSE2 control and status word */
+ fldcw 0x44(%rsi) /* restore x87 control word */
+
+ movq %rdx, %rax /* use third arg as return value after jump */
+
+ movq 0x30(%rsi), %rsp /* restore RSP */
+ movq 0x38(%rsi), %rcx /* fetch the address to return to */
+ movq %r13, %rdi /* restore void pointer as argument */
+
+ jmp *%rcx /* indirect jump to context */
+.size boost_fcontext_jump,.-boost_fcontext_jump
+
+.text
+.globl boost_fcontext_make
+.type boost_fcontext_make,@function
+.align 16
+boost_fcontext_make:
+ movq %rdi, (%rdi) /* save the address of current context */
+ movq %rsi, 0x38(%rdi) /* save the address of the function supposed to run */
+ movq %rdx, 0x10(%rdi) /* save the the void pointer */
+ movq 0x48(%rdi), %rdx /* load the stack base */
+
+ pushq %rdi /* save pointer to fcontext_t */
+ movq %rdx, %rdi /* stack pointer as arg for boost_fcontext_align */
+ call boost_fcontext_align_at_PLT /* align stack */
+ movq %rax, %rdx /* begin of aligned stack */
+ popq %rdi /* restore pointer to fcontext_t */
+
+ leaq -0x8(%rdx), %rdx /* reserve space for the last frame on stack, (RSP + 8) % 16 == 0 */
+ movq %rdx, 0x30(%rdi) /* save the address */
+ movq 0x58(%rdi), %rcx /* load the address of the next context */
+ movq %rcx, 0x8(%rdi) /* save the address of next context */
+ stmxcsr 0x40(%rdi) /* save SSE2 control and status word */
+ fnstcw 0x44(%rdi) /* save x87 control word */
+ leaq link_fcontext(%rip), %rcx /* helper code executed after context function returns */
+ movq %rcx, (%rdx)
+ xorq %rax, %rax /* set RAX to zero */
+ ret
+
+link_fcontext:
+ movq %r12, %rsi /* restore next context */
+ testq %rsi, %rsi /* test if a next context was given */
+ je 1f /* jump to finish */
+
+ movq %rbx, %rdi /* restore current context */
+ call boost_fcontext_start_at_PLT /* jump to next context */
+
+1:
+ xorq %rdi, %rdi /* exit code is zero */
+ call _exit_at_PLT /* exit application */
+ hlt
+.size boost_fcontext_make,.-boost_fcontext_make
+

Added: trunk/libs/context/src/asm/fcontext_x86_64_sysv_macho_gas.S
==============================================================================
--- (empty file)
+++ trunk/libs/context/src/asm/fcontext_x86_64_sysv_macho_gas.S 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,122 @@
+/*
+ Copyright Oliver Kowalke 2009.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt)
+*/
+
+/****************************************************************************************
+ * *
+ * ---------------------------------------------------------------------------------- *
+ * | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | *
+ * ---------------------------------------------------------------------------------- *
+ * | 0x0 | 0x4 | 0x8 | 0xc | 0x10 | 0x14 | 0x18 | 0x1c | *
+ * ---------------------------------------------------------------------------------- *
+ * | RBX | R12 | R13 | R14 | *
+ * ---------------------------------------------------------------------------------- *
+ * ---------------------------------------------------------------------------------- *
+ * | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | *
+ * ---------------------------------------------------------------------------------- *
+ * | 0x20 | 0x24 | 0x28 | 0x2c | 0x30 | 0x34 | 0x38 | 0x3c | *
+ * ---------------------------------------------------------------------------------- *
+ * | R15 | RBP | RSP | RIP | *
+ * ---------------------------------------------------------------------------------- *
+ * ---------------------------------------------------------------------------------- *
+ * | 16 | 17 | | *
+ * ---------------------------------------------------------------------------------- *
+ * | 0x40 | 0x44 | | *
+ * ---------------------------------------------------------------------------------- *
+ * | fc_mxcsr|fc_x87_cw| | *
+ * ---------------------------------------------------------------------------------- *
+ * ---------------------------------------------------------------------------------- *
+ * | 18 | 19 | 20 | 21 | | *
+ * ---------------------------------------------------------------------------------- *
+ * | 0x48 | 0x4c | 0x50 | 0x54 | | *
+ * ---------------------------------------------------------------------------------- *
+ * | sbase | slimit | | *
+ * ---------------------------------------------------------------------------------- *
+ * ---------------------------------------------------------------------------------- *
+ * | 22 | 23 | | *
+ * ---------------------------------------------------------------------------------- *
+ * | 0x58 | 0x5c | | *
+ * ---------------------------------------------------------------------------------- *
+ * | fc_link | | *
+ * ---------------------------------------------------------------------------------- *
+ * *
+ * **************************************************************************************/
+
+.text
+.globl _boost_fcontext_jump
+.align 8
+_boost_fcontext_jump:
+ movq %rbx, (%rdi) /* save RBX */
+ movq %r12, 0x8(%rdi) /* save R12 */
+ movq %r13, 0x10(%rdi) /* save R13 */
+ movq %r14, 0x18(%rdi) /* save R14 */
+ movq %r15, 0x20(%rdi) /* save R15 */
+ movq %rbp, 0x28(%rdi) /* save RBP */
+
+ stmxcsr 0x40(%rdi) /* save SSE2 control and status word */
+ fnstcw 0x44(%rdi) /* save x87 control word */
+
+ leaq 0x8(%rsp), %rcx /* exclude the return address and save as stack pointer */
+ movq %rcx, 0x30(%rdi) /* save as stack pointer */
+ movq (%rsp), %rcx /* save return address */
+ movq %rcx, 0x38(%rdi) /* save return address as RIP */
+
+
+ movq (%rsi), %rbx /* restore RBX */
+ movq 0x8(%rsi), %r12 /* restore R12 */
+ movq 0x10(%rsi), %r13 /* restore R13 */
+ movq 0x18(%rsi), %r15 /* restore R14 */
+ movq 0x20(%rsi), %r15 /* restore R15 */
+ movq 0x28(%rsi), %rbp /* restore RBP */
+
+ ldmxcsr 0x41(%rsi) /* restore SSE2 control and status word */
+ fldcw 0x44(%rsi) /* restore x87 control word */
+
+ movq %rdx, %rax /* use third arg as return value after jump */
+
+ movq 0x30(%rsi), %rsp /* restore RSP */
+ movq 0x38(%rsi), %rcx /* fetch the address to return to */
+ movq %r13, %rdi /* restore RDI */
+
+ jmp *%rcx /* indirect jump to context */
+
+.text
+.globl _boost_fcontext_make
+.align 8
+_boost_fcontext_make:
+ movq %rdi, (%rdi) /* save the address of current context */
+ movq %rsi, 0x38(%rdi) /* save the address of the function supposed to run */
+ movq %rdx, 0x10(%rdi) /* save the the void pointer */
+ movq 0x48(%rdi), %rdx /* load the stack base */
+
+ pushq %rdi /* save pointer to fcontext_t */
+ movq %rdx, %rdi /* stack pointer as arg for boost_fcontext_align */
+ call boost_fcontext_align_at_PLT /* align stack */
+ movq %rax, %rdx /* begin of aligned stack */
+ popq %rdi /* restore pointer to fcontext_t */
+
+ leaq -0x8(%rdx), %rdx /* reserve space for the last frame on stack, (RSP + 8) % 16 == 0 */
+ movq %rdx, 0x30(%rdi) /* save the address */
+ movq 0x58(%rdi), %rcx /* load the address of the next context */
+ movq %rcx, 0x8(%rdi) /* save the address of next context */
+ stmxcsr 0x40(%rdi) /* save SSE2 control and status word */
+ fnstcw 0x44(%rdi) /* save x87 control word */
+ leaq link_fcontext(%rip), %rcx /* helper code executed after fn() returns */
+ movq %rcx, (%rdx)
+ xorq %rax, %rax /* set RAX to zero */
+ ret
+
+link_fcontext:
+ movq %r12, %rsi /* restore next context */
+ testq %rsi, %rsi /* test if a next context was given */
+ je 1f /* jump to finish */
+
+ movq %rbx, %rdi /* restore current context */
+ call _boost_fcontext_start /* install next context */
+
+1:
+ xorq %rdi, %rdi /* exit code is zero */
+ call _exit /* exit application */

Added: trunk/libs/context/src/fcontext.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/src/fcontext.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,38 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#define BOOST_CONTEXT_SOURCE
+
+#include <boost/context/fcontext.hpp>
+
+#include <cstddef>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace contexts {
+
+extern "C" BOOST_CONTEXT_DECL void * BOOST_CONTEXT_CALLDECL boost_fcontext_align( void * vp)
+{
+ void * base = vp;
+ if ( 0 != ( ( ( uintptr_t) base) & 15) )
+ base = ( char * )(
+ ( ( ( ( uintptr_t) base) - 16) >> 4) << 4);
+ return base;
+}
+
+# if !defined(__arm__) && !defined(__powerpc__)
+extern "C" BOOST_CONTEXT_DECL intptr_t BOOST_CONTEXT_CALLDECL boost_fcontext_start( boost_fcontext_t * ofc, boost_fcontext_t const* nfc)
+{ return boost_fcontext_jump( ofc, nfc, 0); }
+#endif
+
+}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif

Added: trunk/libs/context/src/seh.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/src/seh.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,77 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#define BOOST_CONTEXT_SOURCE
+
+extern "C" {
+
+#include <stddef.h>
+#include <stdio.h>
+
+#include <windows.h>
+#include <winnt.h>
+
+static char * exception_description(
+ _EXCEPTION_RECORD const* record, char * description, size_t len)
+{
+ const DWORD code = record->ExceptionCode;
+ const ULONG_PTR * info = record->ExceptionInformation;
+
+ switch ( code)
+ {
+ case EXCEPTION_ACCESS_VIOLATION:
+ {
+ const char * accessType = ( info[0]) ? "writing" : "reading";
+ const ULONG_PTR address = info[1];
+ _snprintf_s( description, len, _TRUNCATE, "Access violation %s 0x%08X", accessType, address);
+ return description;
+ }
+ case EXCEPTION_DATATYPE_MISALIGNMENT: return "Datatype misalignment";
+ case EXCEPTION_BREAKPOINT: return "Breakpoint";
+ case EXCEPTION_SINGLE_STEP: return "Single step";
+ case EXCEPTION_ARRAY_BOUNDS_EXCEEDED: return "Array bounds exceeded";
+ case EXCEPTION_FLT_DENORMAL_OPERAND: return "FPU denormal operand";
+ case EXCEPTION_FLT_DIVIDE_BY_ZERO: return "FPU divide by zero";
+ case EXCEPTION_FLT_INEXACT_RESULT: return "FPU inexact result";
+ case EXCEPTION_FLT_INVALID_OPERATION: return "FPU invalid operation";
+ case EXCEPTION_FLT_OVERFLOW: return "FPU overflow";
+ case EXCEPTION_FLT_STACK_CHECK: return "FPU stack check";
+ case EXCEPTION_FLT_UNDERFLOW: return "FPU underflow";
+ case EXCEPTION_INT_DIVIDE_BY_ZERO: return "Integer divide by zero";
+ case EXCEPTION_INT_OVERFLOW: return "Integer overflow";
+ case EXCEPTION_PRIV_INSTRUCTION: return "Privileged instruction";
+ case EXCEPTION_IN_PAGE_ERROR: return "In page error";
+ case EXCEPTION_ILLEGAL_INSTRUCTION: return "Illegal instruction";
+ case EXCEPTION_NONCONTINUABLE_EXCEPTION: return "Noncontinuable exception";
+ case EXCEPTION_STACK_OVERFLOW: return "Stack overflow";
+ case EXCEPTION_INVALID_DISPOSITION: return "Invalid disposition";
+ case EXCEPTION_GUARD_PAGE: return "Guard page";
+ case EXCEPTION_INVALID_HANDLE: return "Invalid handle";
+ }
+
+ _snprintf_s( description, len, _TRUNCATE, "Unknown (0x%08X)", code);
+
+ return description;
+}
+
+EXCEPTION_DISPOSITION boost_fcontext_seh(
+ struct _EXCEPTION_RECORD * record,
+ void * frame,
+ struct _CONTEXT * ctx,
+ void * dispatcher)
+{
+ char description[255];
+
+ fprintf( stderr, "exception: %s (%08X)\n",
+ exception_description( record, description, sizeof( description) ),
+ record->ExceptionCode);
+
+ ExitProcess( -1);
+
+ return ExceptionContinueSearch; // never reached
+}
+
+}

Added: trunk/libs/context/src/stack_allocator_posix.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/src/stack_allocator_posix.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,84 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#define BOOST_CONTEXT_SOURCE
+
+#include <boost/context/stack_allocator.hpp>
+
+extern "C" {
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+}
+
+#include <stdexcept>
+
+#include <boost/config.hpp>
+#include <boost/assert.hpp>
+#include <boost/format.hpp>
+
+#include <boost/context/stack_utils.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace contexts {
+
+void *
+stack_allocator::allocate( std::size_t size) const
+{
+ if ( minimum_stacksize() > size)
+ throw std::invalid_argument(
+ boost::str( boost::format("invalid stack size: must be at least %d bytes")
+ % minimum_stacksize() ) );
+
+ if ( ! is_stack_unbound() && ( maximum_stacksize() < size) )
+ throw std::invalid_argument(
+ boost::str( boost::format("invalid stack size: must not be larger than %d bytes")
+ % maximum_stacksize() ) );
+
+ const std::size_t pages( page_count( size) + 1); // add +1 for guard page
+ std::size_t size_ = pages * pagesize();
+
+ const int fd( ::open("/dev/zero", O_RDONLY) );
+ BOOST_ASSERT( -1 != fd);
+ void * limit =
+# if defined(macintosh) || defined(__APPLE__) || defined(__APPLE_CC__)
+ ::mmap( 0, size_, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
+# else
+ ::mmap( 0, size_, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
+# endif
+ ::close( fd);
+ if ( ! limit) throw std::bad_alloc();
+
+ const int result( ::mprotect( limit, pagesize(), PROT_NONE) );
+ BOOST_ASSERT( 0 == result);
+
+ return static_cast< char * >( limit) + size_;
+}
+
+void
+stack_allocator::deallocate( void * vp, std::size_t size) const
+{
+ if ( vp)
+ {
+ const std::size_t pages( page_count( size) + 1); // add +1 for guard page
+ std::size_t size_ = pages * pagesize();
+ BOOST_ASSERT( 0 < size && 0 < size_);
+ void * limit = static_cast< char * >( vp) - size_;
+ ::munmap( limit, size_);
+ }
+}
+
+}}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif

Added: trunk/libs/context/src/stack_allocator_windows.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/src/stack_allocator_windows.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,85 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#define BOOST_CONTEXT_SOURCE
+
+#include <boost/context/stack_allocator.hpp>
+
+extern "C" {
+#include <windows.h>
+}
+
+#include <stdexcept>
+
+#include <boost/config.hpp>
+#include <boost/assert.hpp>
+#include <boost/format.hpp>
+
+#include <boost/context/stack_utils.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+# if defined(BOOST_MSVC)
+# pragma warning(push)
+# pragma warning(disable:4244 4267)
+# endif
+
+namespace boost {
+namespace contexts {
+
+void *
+stack_allocator::allocate( std::size_t size) const
+{
+ if ( minimum_stacksize() > size)
+ throw std::invalid_argument(
+ boost::str( boost::format("invalid stack size: must be at least %d bytes")
+ % minimum_stacksize() ) );
+
+ if ( ! is_stack_unbound() && ( maximum_stacksize() < size) )
+ throw std::invalid_argument(
+ boost::str( boost::format("invalid stack size: must not be larger than %d bytes")
+ % maximum_stacksize() ) );
+
+ const std::size_t pages( page_count( size) + 1); // add +1 for guard page
+ std::size_t size_ = pages * pagesize();
+
+#ifndef BOOST_CONTEXT_FIBER
+ void * limit = ::VirtualAlloc( 0, size_, MEM_COMMIT, PAGE_READWRITE);
+ if ( ! limit) throw std::bad_alloc();
+
+ DWORD old_options;
+ const BOOL result = ::VirtualProtect(
+ limit, pagesize(), PAGE_READWRITE | PAGE_GUARD /*PAGE_NOACCESS*/, & old_options);
+ BOOST_ASSERT( FALSE != result);
+
+ return static_cast< char * >( limit) + size_;
+#endif
+}
+
+void
+stack_allocator::deallocate( void * vp, std::size_t size) const
+{
+ if ( vp)
+ {
+ const std::size_t pages( page_count( size) + 1); // add +1 for guard page
+ std::size_t size_ = pages * pagesize();
+ BOOST_ASSERT( 0 < size && 0 < size_);
+ void * limit = static_cast< char * >( vp) - size_;
+ ::VirtualFree( limit, 0, MEM_RELEASE);
+ }
+}
+
+}}
+
+# if defined(BOOST_MSVC)
+# pragma warning(pop)
+# endif
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_SUFFIX
+#endif

Added: trunk/libs/context/src/stack_utils_posix.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/src/stack_utils_posix.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,80 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#define BOOST_CONTEXT_SOURCE
+
+#include <boost/context/stack_utils.hpp>
+
+extern "C" {
+#include <sys/resource.h>
+#include <sys/time.h>
+#include <unistd.h>
+}
+
+#include <cmath>
+#include <csignal>
+
+#include <boost/assert.hpp>
+
+namespace {
+
+static rlimit stacksize_limit_()
+{
+ rlimit limit;
+ const int result = ::getrlimit( RLIMIT_STACK, & limit);
+ BOOST_ASSERT( 0 == result);
+ return limit;
+}
+
+static rlimit stacksize_limit()
+{
+ static rlimit limit = stacksize_limit_();
+ return limit;
+}
+
+}
+
+namespace boost {
+namespace contexts {
+
+BOOST_CONTEXT_DECL
+std::size_t default_stacksize()
+{
+ static std::size_t size = 256 * 1024;
+ return size;
+}
+
+BOOST_CONTEXT_DECL
+std::size_t minimum_stacksize()
+{ return SIGSTKSZ; }
+
+BOOST_CONTEXT_DECL
+std::size_t maximum_stacksize()
+{
+ BOOST_ASSERT( ! is_stack_unbound() );
+ return static_cast< std::size_t >( stacksize_limit().rlim_max);
+}
+
+BOOST_CONTEXT_DECL
+bool is_stack_unbound()
+{ return RLIM_INFINITY == stacksize_limit().rlim_max; }
+
+BOOST_CONTEXT_DECL
+std::size_t pagesize()
+{
+ static std::size_t pagesize( ::getpagesize() );
+ return pagesize;
+}
+
+BOOST_CONTEXT_DECL
+std::size_t page_count( std::size_t stacksize)
+{
+ return static_cast< std::size_t >(
+ std::ceil(
+ static_cast< float >( stacksize) / pagesize() ) );
+}
+
+}}

Added: trunk/libs/context/src/stack_utils_windows.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/src/stack_utils_windows.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,84 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#define BOOST_CONTEXT_SOURCE
+
+#include <boost/context/stack_utils.hpp>
+
+extern "C" {
+#include <windows.h>
+}
+
+#include <cmath>
+#include <csignal>
+
+#include <boost/assert.hpp>
+
+namespace {
+
+static SYSTEM_INFO system_info_()
+{
+ SYSTEM_INFO si;
+ ::GetSystemInfo( & si);
+ return si;
+}
+
+static SYSTEM_INFO system_info()
+{
+ static SYSTEM_INFO si = system_info_();
+ return si;
+}
+
+}
+
+namespace boost {
+namespace contexts {
+
+BOOST_CONTEXT_DECL
+std::size_t default_stacksize()
+{
+ static std::size_t size = 256 * 1024;
+ return size;
+}
+
+BOOST_CONTEXT_DECL
+std::size_t minimum_stacksize()
+{
+ static std::size_t stacksize(
+ static_cast< std::size_t >( system_info().dwAllocationGranularity) );
+ return stacksize;
+}
+
+BOOST_CONTEXT_DECL
+std::size_t maximum_stacksize()
+{
+ BOOST_ASSERT( ! is_stack_unbound() );
+ static std::size_t stacksize = 8 * 1024 * 1024;
+ return stacksize;
+}
+
+// Windows seams not to provide a limit for the stacksize
+BOOST_CONTEXT_DECL
+bool is_stack_unbound()
+{ return true; }
+
+BOOST_CONTEXT_DECL
+std::size_t pagesize()
+{
+ static std::size_t pagesize(
+ static_cast< std::size_t >( system_info().dwPageSize) );
+ return pagesize;
+}
+
+BOOST_CONTEXT_DECL
+std::size_t page_count( std::size_t stacksize)
+{
+ return static_cast< std::size_t >(
+ std::ceil(
+ static_cast< float >( stacksize) / pagesize() ) );
+}
+
+}}

Added: trunk/libs/context/test/Jamfile.v2
==============================================================================
--- (empty file)
+++ trunk/libs/context/test/Jamfile.v2 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,25 @@
+# Boost.Context Library Tests Jamfile
+
+# Copyright Oliver Kowalke 2009.
+# Distributed under the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE_1_0.txt or copy at
+# http://www.boost.org/LICENSE_1_0.txt)
+
+import common ;
+import feature ;
+import indirect ;
+import modules ;
+import os ;
+import testing ;
+import toolset ;
+
+project boost/context/test
+ : requirements
+ <library>../../test/build//boost_unit_test_framework
+ <library>/boost/context//boost_context
+ <link>static
+ ;
+
+test-suite "context" :
+ [ run test_context.cpp ]
+ ;

Added: trunk/libs/context/test/test_context.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/context/test/test_context.cpp 2012-02-11 08:04:55 EST (Sat, 11 Feb 2012)
@@ -0,0 +1,203 @@
+
+// Copyright Oliver Kowalke 2009.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <iostream>
+#include <sstream>
+#include <stdexcept>
+#include <string>
+
+#include <boost/assert.hpp>
+#include <boost/test/unit_test.hpp>
+#include <boost/utility.hpp>
+
+#include <boost/context/all.hpp>
+
+int value1 = 0;
+std::string value2, value3;
+
+class X : private boost::noncopyable
+{
+private:
+ std::string str_;
+
+public:
+ X( std::string const& str) :
+ str_( str)
+ {}
+
+ ~X()
+ { value3 = str_; }
+};
+
+boost::contexts::context gctx;
+
+void fn0()
+{}
+
+void fn1( int i)
+{ value1 = i; }
+
+void fn2( std::string const& str)
+{
+ try
+ { throw std::runtime_error( str); }
+ catch ( std::runtime_error const& e)
+ { value2 = e.what(); }
+}
+
+void fn3( std::string const& str)
+{
+ X x( str);
+ intptr_t vp = gctx.suspend( value1);
+ value1 = vp;
+ gctx.suspend();
+}
+
+void fn4( std::string const& str1, std::string const& str2)
+{
+ value2 = str1;
+ value3 = str2;
+}
+
+void fn5( double d)
+{
+ d += 3.45;
+ std::cout << "d == " << d << std::endl;
+}
+
+void test_case_1()
+{
+ boost::contexts::context ctx1;
+ boost::contexts::context ctx2(
+ fn0,
+ boost::contexts::default_stacksize(),
+ boost::contexts::stack_unwind, boost::contexts::return_to_caller);
+ BOOST_CHECK( ! ctx1);
+ BOOST_CHECK( ctx2);
+ ctx1 = boost::move( ctx2);
+ BOOST_CHECK( ctx1);
+ BOOST_CHECK( ! ctx2);
+}
+
+void test_case_2()
+{
+ boost::contexts::context ctx(
+ fn0,
+ boost::contexts::default_stacksize(),
+ boost::contexts::stack_unwind, boost::contexts::return_to_caller);
+ BOOST_CHECK( ! ctx.is_complete() );
+ ctx.start();
+ BOOST_CHECK( ctx.is_complete() );
+}
+
+void test_case_3()
+{
+ int i = 1;
+ BOOST_CHECK_EQUAL( 0, value1);
+ boost::contexts::context ctx(
+ fn1, i,
+ boost::contexts::default_stacksize(),
+ boost::contexts::stack_unwind, boost::contexts::return_to_caller);
+ BOOST_CHECK( ! ctx.is_complete() );
+ ctx.start();
+ BOOST_CHECK( ctx.is_complete() );
+ BOOST_CHECK_EQUAL( 1, value1);
+}
+
+void test_case_4()
+{
+ BOOST_CHECK_EQUAL( std::string(""), value2);
+ boost::contexts::context ctx(
+ fn2, "abc",
+ boost::contexts::default_stacksize(),
+ boost::contexts::stack_unwind, boost::contexts::return_to_caller);
+ BOOST_CHECK( ! ctx.is_complete() );
+ ctx.start();
+ BOOST_CHECK( ctx.is_complete() );
+ BOOST_CHECK_EQUAL( std::string("abc"), value2);
+}
+
+void test_case_5()
+{
+ value1 = 1;
+ BOOST_CHECK_EQUAL( 1, value1);
+ BOOST_CHECK_EQUAL( std::string(""), value3);
+ gctx = boost::contexts::context(
+ fn3, "abc",
+ boost::contexts::default_stacksize(),
+ boost::contexts::stack_unwind, boost::contexts::return_to_caller);
+ BOOST_CHECK( ! gctx.is_complete() );
+ intptr_t vp = gctx.start();
+ BOOST_CHECK_EQUAL( vp, value1);
+ BOOST_CHECK_EQUAL( 1, value1);
+ BOOST_CHECK( ! gctx.is_complete() );
+ int x = 7;
+ vp = 0;
+ vp = gctx.resume( x);
+ BOOST_CHECK_EQUAL( 7, value1);
+ BOOST_CHECK( ! vp);
+ BOOST_CHECK( ! gctx.is_complete() );
+ BOOST_CHECK_EQUAL( std::string(""), value3);
+ gctx.unwind_stack();
+ BOOST_CHECK( gctx.is_complete() );
+ BOOST_CHECK_EQUAL( std::string("abc"), value3);
+}
+
+void test_case_6()
+{
+ value1 = 0;
+ value2 = "";
+ value3 = "";
+ BOOST_CHECK_EQUAL( 0, value1);
+ BOOST_CHECK_EQUAL( std::string(""), value2);
+ BOOST_CHECK_EQUAL( std::string(""), value3);
+
+ boost::contexts::context ctx1(
+ fn4, "abc", "xyz",
+ boost::contexts::default_stacksize(),
+ boost::contexts::stack_unwind, boost::contexts::return_to_caller);
+ boost::contexts::context ctx2(
+ fn1, 7,
+ boost::contexts::default_stacksize(),
+ boost::contexts::stack_unwind, ctx1);
+
+ BOOST_CHECK( ! ctx1.is_complete() );
+ BOOST_CHECK( ! ctx2.is_complete() );
+ ctx2.start();
+// BOOST_CHECK( ctx1.is_complete() );
+// BOOST_CHECK( ctx2.is_complete() );
+//
+// BOOST_CHECK_EQUAL( 7, value1);
+// BOOST_CHECK_EQUAL( "abc", value2);
+// BOOST_CHECK_EQUAL( "xyz", value3);
+}
+
+void test_case_7()
+{
+ boost::contexts::context ctx(
+ fn5, 7.34,
+ boost::contexts::default_stacksize(),
+ boost::contexts::stack_unwind, boost::contexts::return_to_caller);
+ BOOST_CHECK( ! ctx.is_complete() );
+ ctx.start();
+ BOOST_CHECK( ctx.is_complete() );
+}
+
+boost::unit_test::test_suite * init_unit_test_suite( int, char* [])
+{
+ boost::unit_test::test_suite * test =
+ BOOST_TEST_SUITE("Boost.Context: context test suite");
+
+ test->add( BOOST_TEST_CASE( & test_case_1) );
+ test->add( BOOST_TEST_CASE( & test_case_2) );
+ test->add( BOOST_TEST_CASE( & test_case_3) );
+ test->add( BOOST_TEST_CASE( & test_case_4) );
+ test->add( BOOST_TEST_CASE( & test_case_5) );
+ test->add( BOOST_TEST_CASE( & test_case_6) );
+ test->add( BOOST_TEST_CASE( & test_case_7) );
+
+ return test;
+}

Next message: barend.gehrels_at_[hidden]: "[Boost-commit] svn:boost r76975 - trunk/boost/geometry/algorithms/detail/overlay"
Previous message: dnljms_at_[hidden]: "[Boost-commit] svn:boost r76973 - trunk/libs/iostreams/test"

Date view	Thread view	Subject view	Author view

Boost-Commit list run by bdawes at acm.org, david.abrahams at rcn.com, gregod at cs.rpi.edu, cpdaniel at pacbell.net, john at johnmaddock.co.uk