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Re: [Boost-users] statechart::asynchronous_state_machine and state-local storage
by Tim Crews (boost) 03 Aug '08

03 Aug '08

Andreas: Thank you for your prompt responses. Also, since I neglected to do so in my initial post, thank you for the statechart library itself. I spent a considerable amount of time implementing (and, alas, debugging) a statechart library of my own in C# a few years ago. When another statechart-based project came along, and it was using C++, I was relieved to learn that your library existed. Returning to the subject at hand: The member variable that I want to share is a single boolean flag. It would only be written by "self", and only read by self's twin. There would not be any member variables that required shared read/write access. I would use the provisions of the Boost thread library to ensure that these accesses were thread-safe, as Igor suggested. But these are moot points if the framework makes such access impossible by design. Given the limited amount of data involved, it will be easy to implement the required communication using an event as you advised. Thanks again, Tim Crews GECO, Inc. >> You can't, see above. Two asynchronous state machine must only exchange >> data in >> a, well, asynchronous manner. That is, have the requesting state machine >> post >> an event to the other FSM, which in turn posts the requested data in an >> event >> back to the requesting FSM. Of course you'll have to be careful to always >> *copy* the data and never let both state machines access the same data >> through >> e.g. pointers. > <snip> It depends on how long the lock is taken by each FSM. If we're just talking lock, read/write, unlock then no I don't think you'd have any problems with just two FSMs. The longer the lock is taken the more could shared data access become a bottleneck and adversely affect performance. Of course, for Tims problem (access of state-local data), this is not a good solution as it would inevitably make the data non-local. Regards, -- Andreas Huber When replying by private email, please remove the words spam and trap from the address shown in the header.

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boost::variant as class member - linker error
by Kevin Martin 02 Aug '08

02 Aug '08

I'm new to boost::variant and I can't seem to use it in a class because I get linker errors. I can't find any reference to this in the archive or the docs so I figure it must be something silly I'm missing. Any help appreciated. The compilation command, error, and files are shown below. Thanks, Kevin Martin g++ -I $BOOSTINC test.cpp a.cpp /usr/lib64/gcc-lib/x86_64-suse-linux/3.3.5/../../../../x86_64-suse- linux/bin/ld: ` .gnu .linkonce .t ._ZN5boost6detail7variant15visitation_implIN4mpl_4int_ILi0EEENS1_20visitation_impl_stepINS_3mpl6l_iterINS7_6l_itemINS3_5long_ILl2EEEiNS9_INSA_ILl1EEESsNS7_5l_endEEEEEEENS8_ISD_EEEENS1_9destroyerEPvNS_7variantIiSsNS1_5void_ESM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_E18has_fallback_type_EEEN7Visitor11result_typeEiiRSP_T2_NS3_5bool_ILb0EEET3_PT_PT0_ ' referenced in section `.rodata' of /tmp/ccZwRSZE.o: defined in discarded section ` .gnu .linkonce .t ._ZN5boost6detail7variant15visitation_implIN4mpl_4int_ILi0EEENS1_20visitation_impl_stepINS_3mpl6l_iterINS7_6l_itemINS3_5long_ILl2EEEiNS9_INSA_ILl1EEESsNS7_5l_endEEEEEEENS8_ISD_EEEENS1_9destroyerEPvNS_7variantIiSsNS1_5void_ESM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_E18has_fallback_type_EEEN7Visitor11result_typeEiiRSP_T2_NS3_5bool_ILb0EEET3_PT_PT0_ ' of /tmp/ccZwRSZE.o The files are: ==== a.h ==== #ifndef __A_HEADER__ #define __A_HEADER__ #include <boost/variant.hpp> #include <string> class A { boost::variant<int, std::string> a; public: void setToString(const std::string &x); void setToInt(int x); int which() const; }; #endif ==== a.cpp ==== #include "a.h" int A::which() const { return this->a.which(); } void A::setToString(const std::string &x) { this->a = x; } void A::setToInt(int x) { this->a = x; } ==== test.cpp ==== #include "a.h" #include <iostream> int main() { A a; a.setToString("abc"); std::cout << a.which() << std::endl; a.setToInt(123); std::cout << a.which() << std::endl; return 0; }

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FW: statechart::asynchronous_state_machine and state-local storage
by Tim Crews (boost) 02 Aug '08

02 Aug '08

Hello: I have two instances of the same state machine, which are launched as asynchronous_state_machines. I also have some state-local storage in these state machines that I would like to be able to access from outside the state machines. Actually, to be more precise, I want each instance of the state machine to be able to access a single member variable of its twin. The problem is, if I create an asynchronous state machine in the usual way (via fifo_scheduler<>::initiate_processor() and fifo_scheduler<>::operator (), it seems that the actual instance of the state machine is buried in the framework somewhere; I don't have access to a pointer to the state machine itself. Can anyone tell me how I go about getting a reference to the state machine that is instantiated when fifo_scheduler<>::initiate_processor is called? Thank you, Tim Crews GECO, Inc.

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program.options: multiple multitokens
by gfsdjkgf＠Safe-mail.net 02 Aug '08

02 Aug '08

Hello, my applications takes two multitoken options via command line. Unfortunately the boost's program options does only allow one multitoken. After the inital multitoken initalizer, any other "initializer" are ingored. test --multitoken_option1 a b c d e f --multitoken_option2 a b c d e <---multitoken_option2 and any other command line options after --multitoken_option are ignored. What can I do? Thank you

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[boost.test] Can't compile basic example: vtable error
by Trevor Bain 02 Aug '08

02 Aug '08

Hello, I'm trying to just do the basic example of boost.test unit testing. I'm getting compilation errors when I include the headers. =============== test.cpp ==================== #define BOOST_TEST_MODULE MyTest #include <boost/test/unit_test.hpp> /* #include <boost/test/unit_test_log.hpp> #include <boost/test/unit_test_log_formatter.hpp> */ int add( int i, int j ) { return i+j; } /* commented out BOOST_AUTO_TEST_CASE( my_test ) { // seven ways to detect and report the same error: BOOST_CHECK( add( 2,2 ) == 4 ); // #1 continues on error BOOST_REQUIRE( add( 2,2 ) == 4 ); // #2 throws on error if( add( 2,2 ) != 4 ) BOOST_ERROR( "Ouch..." ); // #3 continues on error if( add( 2,2 ) != 4 ) BOOST_FAIL( "Ouch..." ); // #4 throws on error if( add( 2,2 ) != 4 ) throw "Ouch..."; // #5 throws on error BOOST_CHECK_MESSAGE( add( 2,2 ) == 4, // #6 continues on error "add(..) result: " << add( 2,2 ) ); BOOST_CHECK_EQUAL( add( 2,2 ), 4 ); // #7 continues on error } */ int main() { return 0; }; =============== test.cpp ==================== To compile I'm doing (I have to add the location of boost to the include path with -I): g++ -I/Users/zara/Programming/polyneuron/lib/boost_1_35_0/ test.cpp The only output is: Undefined symbols: "vtable for boost::unit_test::unit_test_log_t", referenced from: __ZTVN5boost9unit_test15unit_test_log_tE$non_lazy_ptr in ccDfKOkF.o "boost::unit_test::framework::master_test_suite()", referenced from: init_unit_test_suite(int, char**)in ccDfKOkF.o ld: symbol(s) not found collect2: ld returned 1 exit status Which is a virtual function issue ... but why should I be having this in a library I'm using? I shouldn't have to touch the lib code ... what's up? Do I need to implement some virtual function/class? With the code uncommented I get many more errors - and this is the example code given in the docs ... Help is much appreciated. - trevor

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lambda problem
by Tim Hockin 02 Aug '08

02 Aug '08

I use a few lambdas in my application. Simple ones like (_1 + 1) work fine. However, when I use this next one, the compile blows up on me and produces a huge and indecipherable error: if_then_else_return(_1 == 0, 64, _1) Yields: cc1plus: warnings being treated as errors /usr/include/boost/lambda/if.hpp: In member function 'RET boost::lambda::lambda_functor_base<boost::lambda::other_action<boost::lambda::ifthenelsereturn_action>, Args>::call(A&, B&, C&, Env&) const [with RET = const bignum&, A = const bignum, B = const boost::tuples::null_type, C = const boost::tuples::null_type, Env = const boost::tuples::null_type, Args = boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::relational_action<boost::lambda::equal_action>, boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, const int, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> > >, const int, boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>]': /usr/include/boost/lambda/detail/lambda_functors.hpp:148: instantiated from 'typename T::sig<boost::tuples::tuple<A&, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> >::type boost::lambda::lambda_functor<Base>::operator()(A&) const [with A = const bignum, T = boost::lambda::lambda_functor_base<boost::lambda::other_action<boost::lambda::ifthenelsereturn_action>, boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::relational_action<boost::lambda::equal_action>, boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, const int, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> > >, const int, boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> >]' ../pp_datatypes.h:454: instantiated from 'std::string pp_transform_datatype<Tdefunc, Tenfunc>::evaluate(const pp_value&) const [with Tdefunc = boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::other_action<boost::lambda::ifthenelsereturn_action>, boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::relational_action<boost::lambda::equal_action>, boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, const int, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> > >, const int, boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> > >, Tenfunc = boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::arithmetic_action<boost::lambda::minus_action>, boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, const int, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> > >]' cpuid/generic_device.cpp:915: instantiated from here /usr/include/boost/lambda/if.hpp:315: warning: returning reference to temporary (this is with GCC 4.x) and _1 is a GMPXX bignum So I tried to boil it down, and I ran into a slightly different error. This code: #include <boost/lambda/lambda.hpp> #include <boost/lambda/if.hpp> #include <iostream> using namespace boost::lambda; int real_func(int x) { return x+10; } struct functor { int operator()(int x) { return x+20; } }; template <typename T> struct functor_templ { T operator()(T x) { return x+30; } }; template <typename T> int call_this(T func) { return func(make_const(0)); } int main() { int a = call_this(&real_func); if (a != 10) std::cerr << "a != 10" << std::endl; int b = call_this(functor()); if (b != 20) std::cerr << "b != 20" << std::endl; int c = call_this(functor_templ<int>()); if (c != 30) std::cerr << "c != 30" << std::endl; int x = call_this(_1+40); if (x != 40) std::cerr << "x != 40" << std::endl; int y = call_this(if_then_else_return(_1 == 0, 50, _1)); return 0; } blows up on the if_then_else_return: lambda_crap.cpp: In function 'int call_this(T) [with T = boost::lambda::lambda_f unctor<boost::lambda::lambda_functor_base<boost::lambda::other_action<boost::lam bda::ifthenelsereturn_action>, boost::tuples::tuple<boost::lambda::lambda_functo r<boost::lambda::lambda_functor_base<boost::lambda::relational_action<boost::lam bda::equal_action>, boost::tuples::tuple<boost::lambda::lambda_functor<boost::la mbda::placeholder<1> >, const int, boost::tuples::null_type, boost::tuples::null _type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_t ype, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_typ e> > >, const int, boost::lambda::lambda_functor<boost::lambda::placeholder<1> > , boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, bo ost::tuples::null_type> > >]': lambda_crap.cpp:49: instantiated from here lambda_crap.cpp:35: error: cannot convert 'const boost::lambda::detail::return_t ype_deduction_failure<boost::lambda::detail::return_type_2_ifthenelsereturn<1, t rue, true, false, const int, const int&> >' to 'int' in return /usr/include/boost/lambda/if.hpp: In member function 'RET boost::lambda::lambda_ functor_base<boost::lambda::other_action<boost::lambda::ifthenelsereturn_action> , Args>::call(A&, B&, C&, Env&) const [with RET = const boost::lambda::detail::r eturn_type_deduction_failure<boost::lambda::detail::return_type_2_ifthenelseretu rn<1, true, true, false, const int, const int&> >, A = const int, B = const boos t::tuples::null_type, C = const boost::tuples::null_type, Env = const boost::tup les::null_type, Args = boost::tuples::tuple<boost::lambda::lambda_functor<boost: :lambda::lambda_functor_base<boost::lambda::relational_action<boost::lambda::equ al_action>, boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::pl aceholder<1> >, const int, boost::tuples::null_type, boost::tuples::null_type, b oost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boo st::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> > >, const int, boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, boost: :tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::t uples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tup les::null_type>]': /usr/include/boost/lambda/detail/lambda_functors.hpp:148: instantiated from 't ypename T::sig<boost::tuples::tuple<A&, boost::tuples::null_type, boost::tuples: :null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::n ull_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::nul l_type, boost::tuples::null_type> >::type boost::lambda::lambda_functor<Base>::o perator()(A&) const [with A = const int, T = boost::lambda::lambda_functor_base< boost::lambda::other_action<boost::lambda::ifthenelsereturn_action>, boost::tupl es::tuple<boost::lambda::lambda_functor<boost::lambda::lambda_functor_base<boost ::lambda::relational_action<boost::lambda::equal_action>, boost::tuples::tuple<b oost::lambda::lambda_functor<boost::lambda::placeholder<1> >, const int, boost:: tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tu ples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tupl es::null_type, boost::tuples::null_type> > >, const int, boost::lambda::lambda_f unctor<boost::lambda::placeholder<1> >, boost::tuples::null_type, boost::tuples: :null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::n ull_type, boost::tuples::null_type, boost::tuples::null_type> >]' lambda_crap.cpp:35: instantiated from 'int call_this(T) [with T = boost::lambd a::lambda_functor<boost::lambda::lambda_functor_base<boost::lambda::other_action <boost::lambda::ifthenelsereturn_action>, boost::tuples::tuple<boost::lambda::la mbda_functor<boost::lambda::lambda_functor_base<boost::lambda::relational_action <boost::lambda::equal_action>, boost::tuples::tuple<boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, const int, boost::tuples::null_type, boost::t uples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tup les::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuple s::null_type> > >, const int, boost::lambda::lambda_functor<boost::lambda::place holder<1> >, boost::tuples::null_type, boost::tuples::null_type, boost::tuples:: null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::nu ll_type, boost::tuples::null_type> > >]' lambda_crap.cpp:49: instantiated from here /usr/include/boost/lambda/if.hpp:315: error: conversion from 'const int' to non- scalar type 'const boost::lambda::detail::return_type_deduction_failure<boost::l ambda::detail::return_type_2_ifthenelsereturn<1, true, true, false, const int, c onst int&> >' requested make: *** [lambda_crap] Error 1 How can I do this? I want to write a lamba that simply says "if (_1 == 0) return 64; else return _1; Thanks!! Tim

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[1.36.0 beta] Beta release available on SourceForge
by Beman Dawes 02 Aug '08

02 Aug '08

New libraries: Accumulators, Exception, Units, Unordered. Updated Libraries: Assign, Foreach, Interprocess, Intrusive, Math, Multi-index Containers, PtrContainer, Spirit, Thread, Xpressive, plus a bunch more. Many thanks to Daniel James, Rene Rivera, Marshall Clow, Eric Niebler, the testers, and all the others who helped to get this beta release together. The beta period will be approximately one week. Please post bug reports here, but also let us hear about success stories too! --Beman

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[boost] [interprocess] Semaphore cleanup after crash
by Sachin Garg 02 Aug '08

02 Aug '08

When using semaphores to synchronize separate processes, everything works fine when each process exits nicely (closing its semaphores before exit). But things get really messy when a process might crash. I am unable to figure out how to recover from such a crash which leaves semaphores in inconsistent state. If a semaphore is not in-use (open) by any process, in this case (in my application) I can safely 'remove' it and start afresh. Is there some way to find out if any process is using a semaphore at a time so that I can call 'remove'? When I just add a 'remove' on process start this works great on windows (as remove just fails if another process has the semaphore open), but on linux sem_unlink is used which has the behavior of deleting it even if its in use. What is the general practice when it comes to cleaning up semaphores after process crashes? Maybe some way to ensure that 'post' and 'close' are always called even when application has otherwise crashed? Is there some way to use boost's windows style semaphores on linux instead of native posix style? I tried looking and many have asked this question (in context of recovering from posix semaphores, which are used by boost on linux), but I couldn't find any answers. Lars had asked this here also, almost an year ago but no answers in that thread either. This seems like a basic issue but am totally lost on how to even approach it. Sachin Garg

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Boost.Endian missing integer_cover_operators.hpp
by Seika van Olstroem 02 Aug '08

02 Aug '08

Hello, in 2000 and 2006 Darin Adler and Berman Dawes tried to get a library called Boost.Endian into Boost, but it seems the process stopped somewhere. This library would help me a lot when working with different byte orders. Here are the threads: http://lists.boost.org/Archives/boost/2000/03/2495.php http://lists.boost.org/Archives/boost/2006/06/106655.php Using Google I've found a recent endian.hpp but I can't find integer_cover_operators.hpp. http://lists.boost.org/Archives/boost/att-105789/endian.hpp Berman, what happend with Boost.Endian? -- -Seika

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boost in NT Kernel
by Sam Tertzakian 02 Aug '08

02 Aug '08

Hi, Is it possible to use boost in the "NT Kernel" environment? It seems like I should be able to but I am only able to do so if I modify the library. I assume that there are two possibilities: 1. There is a #define that allows me to use in "NT Kernel". (Or there is some other step I need to do.) 2. boost is not supported (without modification) Thank you

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