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[ptr_container] warnings about shadowed members
by Samuel Landau 27 Oct '05

27 Oct '05

Hello, I am trying Boost 1.33 ptr_container with GCC 4.0.1 on Linux. When including a ptr_container header (say, ptr_vector.hpp), compiling code with the "-Wshadow" flag, some warnings are issued about shadowed members. I am wondering if this might be a problem, even if my snippet code compiles and seems to run fine so far for me. output example (with boost/ in current directory) : $ cat main.cpp #include <boost/ptr_container/ptr_vector.hpp> int main() {} $ g++ -I. -Wshadow main.cpp ./boost/ptr_container/detail/move.hpp: In constructor 'boost::ptr_container_detail::move_ptrs::move_source<Ptr>::move_source(Ptr&)': ./boost/ptr_container/detail/move.hpp:18: warning: declaration of 'ptr' shadows a member of 'this' ./boost/ptr_container/detail/static_move_ptr.hpp: In member function 'void boost::ptr_container_detail::static_move_ptr<T, Deleter>::check(const +boost::ptr_container_detail::static_move_ptr<TT, DD>&)': ./boost/ptr_container/detail/static_move_ptr.hpp:156: warning: declaration of 'ptr' shadows a member of 'this' ./boost/ptr_container/exception.hpp: In constructor 'boost::bad_ptr_container_operation::bad_ptr_container_operation(const char*)': ./boost/ptr_container/exception.hpp:27: warning: declaration of 'what' shadows a member of 'this' ./boost/ptr_container/exception.hpp: In constructor 'boost::bad_index::bad_index(const char*)': ./boost/ptr_container/exception.hpp:41: warning: declaration of 'what' shadows a member of 'this' ./boost/ptr_container/detail/reversible_ptr_container.hpp: In member function 'ForwardIterator +boost::ptr_container_detail::reversible_ptr_container<Config, CloneAllocator>::advance(ForwardIterator, typename Config::void_container_type::size_type)': ./boost/ptr_container/detail/reversible_ptr_container.hpp:287: warning: declaration of 'begin' shadows a member of 'this' -- Samuel Landau

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[boost-users] [MPL.Math] gcd_impl improved
by Cromwell Enage 27 Oct '05

27 Oct '05

The gcd_impl specialization for integral constants is now based on the binary GCD algorithm. BOOST_STATIC_CONSTANT is now used over typedef at most intermediate steps. You should see much faster compile times, at least for the gcd_lcm test and example programs. Cromwell D. Enage __________________________________ Yahoo! FareChase: Search multiple travel sites in one click. http://farechase.yahoo.com

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Re: [Boost-users] multi-inheritance from elements of mpl::vector? ==> inherit_scattered ( for Barton & Nackmann trick)
by Oliver.Kowalke＠infineon.com 27 Oct '05

27 Oct '05

>Is there a page somewhere that describes the trick, just out of interest >like. C++ Template Metaprogramming, page 205 Modern C++ Design, somewhere AFAIK - Barton & Nackmann trick is used for class composition: template< typename Derived > struct Add { int add() { // B & N-trick: access to the Composed class D & d = static_cast< Derived & >( * this); return d.first() + d.second(); } }; struct First { int first() { return 1; } }; struct Second { int second() { return 2; } }; class Composed : inherit_scattered< vector< First, Second, Add< Composed > > > {}; void main() { Composed c; Std::cout << c.add() << std::endl; }

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multi-inheritance from elements of mpl::vector?
by Oliver.Kowalke＠infineon.com 27 Oct '05

27 Oct '05

Hi, how is it possible to inherit from all items inside mpl::vector? template< typename V > class multi : .... // ????? {}; typedef multi < mpl::vector< A ,B, C > > multi _t; multi_t m; // m has all public and protected member functions of A, B and C Best Regards, Oliver

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Re: [Boost-users] multi-inheritance from elements of mpl::vector? ==> inherit_scattered ( for Barton & Nackmann trick)
by Oliver.Kowalke＠infineon.com 27 Oct '05

27 Oct '05

no reply - so I found a solution by myself (used for the Barton & Nackmann trick)! cu, Oliver Code: #include <iostream> #include <cstdlib> #include <string> #include <boost/mpl/begin_end.hpp> #include <boost/mpl/deref.hpp> #include <boost/mpl/next.hpp> #include <boost/mpl/vector.hpp> namespace mpl = boost::mpl; //////////////////////////////////// template< typename B, typename E > struct scattered; template< typename B, typename E > struct scattered : public mpl::deref< B >::type, public scattered< typename mpl::next< B >::type, E > {}; template< typename E > struct scattered< E, E > {}; //////////////////////////////////// template< typename Sequence > struct inherit_scattered : public scattered< typename mpl::begin< Sequence >::type, typename mpl::end< Sequence >::type > {}; //////////////////////////////////// template< typename D > struct F { std::string f() { return static_cast< D & >( * this).str_; } }; template< typename D > struct G { std::string g() { return static_cast< D & >( * this).str_; } }; //////////////////////////////////// class A : public inherit_scattered< mpl::vector< F< A >, G< A > > > { private: template< typename X > friend struct F; template< typename X > friend struct G; std::string str_; public: A( std::string const& str) : str_( str) {} }; int main( int argc, char *argv[]) { A a("Hello World!"); std::cout << a.f() << std::endl; std::cout << a.g() << std::endl; return EXIT_SUCCESS; } >Hi, >how is it possible to inherit from all items inside mpl::vector? > >template< typename V > >class multi >: .... // ????? >{}; > >typedef multi < mpl::vector< A ,B, C > > multi _t; >multi_t m; // m has all public and protected member functions of A, B and C >Best Regards, >Oliver

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plans for boost::sockets library?
by Oliver.Kowalke＠infineon.com 27 Oct '05

27 Oct '05

Hello, is a library for boost::sockets planed? Regards, Oliver

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Re: [Boost-users] multi-inheritance from elements of mpl::vector? ==> inherit_scattered ( for Barton & Nackmann trick)
by Foster, Gareth 27 Oct '05

27 Oct '05

> no reply - so I found a solution by myself (used for the Barton & > Nackmann trick)! > cu, > Oliver > Is there a page somewhere that describes the trick, just out of interest like. Gaz

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Compile boost_wserialization.dll error in CVS of branch RC_1_33_0
by shenhuifeng 27 Oct '05

27 Oct '05

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[Serialization] Fighting code bloat...
by Mats Eklund 27 Oct '05

27 Oct '05

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Re: [Boost-users] Extended Thread object
by Phil Endecott 26 Oct '05

26 Oct '05

>>The actual application is a sort of daemon; a main loop accepts tcp >>connections, and creates a new thread to handle each one. It normally >>wants to "fire and forget" these threads, and I imagine it creating them >>with new() and then letting them dangle, until they eventually terminate >>and delete themselves. > > > I may be missing something here, but if thread lifetime and object > lifetime are not tied, why not create the object on the stack (as part > of an accept() loop, using the tcp connection example). The stack > based object will be destroied each loop, but the thread itself will > continue to exist until it ends. Yes, that's true. I suppose I'm thinking this way because I'm also imagining that I can subclass this new Thread class to add state, e.g. class DaemonThread: public Thread { private: ... per-connection state ... public: DaemonThread(int connection_fd); }; void mainloop() { while(1) { int fd = accept_connection_on_socket(); DaemonThread* handler = new DaemonThread(fd); } } If instead I put the state in another object that's created within the thread's initial function then I can afford for the actual thread object to expire immediately. There must be lots of ways to do this sort of thing. > You could also use boost::call_once to "fire and forget" I think I know what call_once() does but I don't see how it helps. Can you elaborate? Cheers, --Phil.

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