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[thread][move] compiling move(thread) with Android NDK GCC4.7
by Igor R 17 Jan '13

17 Jan '13

Hello, I'm building my project with Android NDK toolchain (Boost1.51, GCC4.6 or GCC4.7), and I get the following error when trying to move thread. Is there any workaround for this issue? //... vector_.push_back(boost::move(thread(&func, arg))); //... try.cpp:86:62: error: no matching function for call to 'move(boost::thread)' try.cpp:86:62: note: candidates are: In file included from boost/thread/detail/move.hpp:20:0, from boost/thread/locks.hpp:11, from boost/thread/pthread/mutex.hpp:12, from boost/thread/mutex.hpp:16, from boost/thread/pthread/thread_data.hpp:13, from boost/thread/thread.hpp:17, from boost/thread.hpp:13, from try.h:3, from try.cpp:6: boost/move/move.hpp:324:97: note: template<class T> typename boost::move_detail::disable_if<boost::has_move_emulation_enabled_aux<T>, T&>::type boost::move(T&) boost/move/move.hpp:324:97: note: template argument deduction/substitution failed: boost/move/move.hpp: In substitution of 'template<class T> typename boost::move_detail::disable_if<boost::has_move_emulation_enabled_aux<T>, T&>::type boost::move(T&) [with T = boost::thread]': try.cpp:86:62: required from here boost/move/move.hpp:324:97: error: no type named 'type' in 'struct boost::move_detail::disable_if<boost::has_move_emulation_enabled_aux<boost::thread>, boost::thread&>' boost/move/move.hpp:330:96: note: template<class T> typename boost::move_detail::enable_if<boost::has_move_emulation_enabled<T>, boost::rv<T>&>::type boost::move(T&) boost/move/move.hpp:330:96: note: template argument deduction/substitution failed: boost/move/move.hpp: In substitution of 'template<class T> typename boost::move_detail::enable_if<boost::has_move_emulation_enabled<T>, boost::rv<T>&>::type boost::move(T&) [with T = boost::thread]': try.cpp:86:62: required from here boost/move/move.hpp:330:96: error: no type named 'type' in 'struct boost::move_detail::enable_if<boost::has_move_emulation_enabled<boost::thread>, boost::rv<boost::thread>&>' boost/move/move.hpp:336:96: note: template<class T> typename boost::move_detail::enable_if<boost::has_move_emulation_enabled<T>, boost::rv<T>&>::type boost::move(boost::rv<T>&) boost/move/move.hpp:336:96: note: template argument deduction/substitution failed: try.cpp:86:62: note: 'boost::thread' is not derived from 'boost::rv<T>' In file included from boost/thread/detail/move.hpp:20:0, from boost/thread/locks.hpp:11, from boost/thread/pthread/mutex.hpp:12, from boost/thread/mutex.hpp:16, from boost/thread/pthread/thread_data.hpp:13, from boost/thread/thread.hpp:17, from boost/thread.hpp:13, from try.h:3, from try.cpp:6: boost/move/move.hpp:943:6: note: template<class I, class O> O boost::move(I, I, O) boost/move/move.hpp:943:6: note: template argument deduction/substitution failed: try.cpp:86:62: note: candidate expects 3 arguments, 1 provided In file included from boost/thread/locks.hpp:11:0, from boost/thread/pthread/mutex.hpp:12, from boost/thread/mutex.hpp:16, from boost/thread/pthread/thread_data.hpp:13, from boost/thread/thread.hpp:17, from boost/thread.hpp:13, from try.h:3, from try.cpp:6: boost/thread/detail/move.hpp:55:124: note: typename boost::enable_if<boost::is_convertible<T&, boost::detail::thread_move_t<T> >, boost::detail::thread_move_t<T> >::type boost::move(T&) [with T = boost::thread; typename boost::enable_if<boost::is_convertible<T&, boost::detail::thread_move_t<T> >, boost::detail::thread_move_t<T> >::type = boost::detail::thread_move_t<boost::thread>] boost/thread/detail/move.hpp:55:124: note: no known conversion for argument 1 from 'boost::thread' to 'boost::thread&' In file included from boost/thread/locks.hpp:11:0, from boost/thread/pthread/mutex.hpp:12, from boost/thread/mutex.hpp:16, from boost/thread/pthread/thread_data.hpp:13, from boost/thread/thread.hpp:17, from boost/thread.hpp:13, from try.h:3, from try.cpp:6: boost/thread/detail/move.hpp:62:37: note: template<class T> boost::detail::thread_move_t<T> boost::move(boost::detail::thread_move_t<T>) boost/thread/detail/move.hpp:62:37: note: template argument deduction/substitution failed: try.cpp:86:62: note: 'boost::thread' is not derived from 'boost::detail::thread_move_t<T>'

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FW: ASIO io_service performance under single or multiple io_services questions
by Bryan Fok 17 Jan '13

17 Jan '13

To asio users, I am confused by the results from my experiments with asio recently. Firstly, am I correct that, when OS I/O buffer is ready to be read, io_service will only pick an available thread from its thread pool to notify the socket's complete handler? For example, if I have a single io_service with 1 thread, and 100 udp sockets executed async_read_from. Hypothetically, if they all simultaneously ready to read from OS kernel buffer, would the io_service notify each socket's complete handler one per time because I only allocated 1 thread to it? Secondly, is it possible to assign workload to different cpu cores through asio? I did an experiment by creating 2 io_services in a program, and each associated with 50 udp sockets for receive same data at the same rate. My theory was that, 2 cores from my 8 cores i7 cpu would be utilize with similar rate, but the result was, only the first core has been fully utilized. Could it be because I/O operation is control by OS only? Thirdly, at what situations should I use multiple threads in a io_service? I increased 50 threads for both io_service in my last experiment setup, and perform the same test. My theory was, when more threads allocated in a io_service , this should help io_service to find a free thread to trigger sockets' complete handler concurrently, therefore, sockets didn't have to wait too long to make the next async read call, and minimize the risk of buffer overflow. The result was completely opposite; the cpu usage has obviously increased, but performance was dramatically decreased because many packet loss was detected. Would it be because of context switching? I thought doesn't matter how many thread were allocated to a io_service, same number of context switching are still required (switching new context from the next complete handler to core to execute after the previous one completed), am I right? B.R Bryan

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[asio][chrono] using steady_timer portably
by Igor R 17 Jan '13

17 Jan '13

Hello, There's some use of asio::steady_timer in my code (1.51): asio::steady_timer timer_; //....... timer_.expires_from_now(boost::chrono::milliseconds(100)); //...... However, the above appears to be non-portable, as under c++11 steady_timer uses std::chrono, while boost::chrono doesn't seem to "forward" its types to std::chrono. I know I can use asio::basic_waitable_timer<boost::chrono::steady_clock> explicitly, but maybe there's some more straightforward solution (eg. boost::chrono configuration)? Thanks.

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Why is boost::format::operator% not declared const?
by Chris Stankevitz 17 Jan '13

17 Jan '13

Hello, I use boost::format to convert a float to a string: void CalledThousandsOfTimesPerSecond(float f) { GetStream() << boost::format("%0.3f") % f << GetSomeOtherContent(); } I normally would deal with something like this by adding a static const variable: void CalledThousandsOfTimesPerSecondFromManyThreads(float f) { static const boost::format Formatter("%0.3f"); GetStream() << Formatter % f << GetSomeOtherContent(); } But this does not work. boost::format::operator% is not declared const. Question 1: Why is boost::format::operator% declared mutable? What is is mutating? Question 2: How do I not spend overhead constructing the same boost::format thousands of times per second? Possible answers to question 2: void CalledThousandsOfTimesPerSecond(float f) { static boost::format Formatter("%0.3f"); // MUTABLE -- this might not be thread safe??? GetStream() << Formatter % f << GetSomeOtherContent(); } void CalledThousandsOfTimesPerSecond(float f) { static const boost::format Formatter1("%0.3f"); boost::format Formatter2(Formatter1); // lame but I guess it works GetStream() << Formatter2 % f << GetSomeOtherContent(); } Thank you, Chris

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Re: [Boost-users] shared memory between 32b and 64b
by Dave Dyer 17 Jan '13

17 Jan '13

Thanks, this pair of definitions gets off the ground. typedef offset_ptr< void , boost::int32_t , boost::uint64_t > my_offset_ptr; typedef basic_managed_shared_memory <char ,rbtree_best_fit<mutex_family, my_offset_ptr> ,iset_index> compat32_shared_memory;

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shared memory between 32b and 64b
by Dave Dyer 16 Jan '13

16 Jan '13

Looked promising, but not quite good enough. I dedined: typedef offset_ptr<class T, std::ptrdiff_t, unsigned long long>my_offset_ptr; typedef basic_managed_shared_memory <char ,rbtree_best_fit<mutex_family, my_offset_ptr> ,iset_index> compat32_shared_memory; in the win64 process I do compat32_shared_memory segment(create_only, SEGMENT_NAME, SEGMENT_SIZE); comm *command = segment.construct<comm>("CommandBlock")(); in the win32 process in do compat32_shared_memory segment(open_only, SEGMENT_NAME); std::pair<comm *,size_t>com = segment.find<comm>("CommandBlock"); the "find" never returns. The code works fine if both processes are win32 or both are win64 Am I on the right track?

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statechart] [gcc-4.7.2] a template state inherited from statechart::state results in compiler error
by Nikiforov Anatoly 15 Jan '13

15 Jan '13

Hi, I'm using Boost.Statechart and have come across a strange gcc-4.7.2 behavior on the attached sample code. The error is: cpp-lab/boost/statechart/main.cpp:89:23: error: expected ')' before 'ctx' If outermost_context() isn't used in Inner3() constructor and statechart::simple_state is used instead of statechart::state everything is OK. If Inner3 is not a template then everything is OK The problem occurs only if a state template class is inherited from statechart::state. Is there any workaround for the issue? Thanks in advance.

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[Property Tree] Debugger visualizer for property tree
by Elizabeta 15 Jan '13

15 Jan '13

Hi I need debugger visualizer for property tree. Can't find it here https://svn.boost.org/svn/boost/sandbox/boost_docs/subprojects/DebuggerVisu…, I guess it doesn't exist. Any plans for making it in near future ?

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64 bits migration problems
by simone pilozzi 15 Jan '13

15 Jan '13

Dear Users, I am experiencing a lot of issues in compiling my VC 2010 projects with a 64 bits machin (while they work happily witha 32 bits). I downloaded the 1_51 version of boost for 64bits and I obtained the following error with the serialization library: Error 495 error LNK1104: cannot open file 'libboost_serialization-vc100-mt-gd-1_51.lib Then I tried some older version ( 1_47, i ) but I received this series of compiling errors related again to the xml archive. Error 493 error LNK2019: unresolved external symbol "protected: __cdecl boost::archive::xml_oarchive_impl<class boost::archive::xml_oarchive>::xml_oarchive_impl<class boost::archive::xml_oarchive>(class std::basic_ostream<char,struct std::char_traits<char> > &,unsigned int)" ( ??0?$xml_oarchive_impl@Vxml_oarchive@archive@boost@@@archive@boost@@IEAA@AEAV?$basic_ostream@DU?$char_traits@D@std@@@std@@I@Z) referenced in function "public: __cdecl boost::archive::xml_oarchive::xml_oarchive(class std::basic_ostream<char,struct std::char_traits<char> > &,unsigned int)" ( ??0xml_oarchive@archive@boost@@QEAA@AEAV?$basic_ostream@DU?$char_traits@D@std@@@std@@I@Z ) Tried to build boost 1_51 with the 64bits using boostrap but it did not find build.bat since it is missing (I found boost-build.jam) Any suggestion?

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Runtime Library Error in C++ called boost.python and custom module
by simon zhang 12 Jan '13

12 Jan '13

I have called some python in C++,then python will called a custom module that was writed by c++. This problem occured when I track, python call custom module. Error: Microsoft Visual C++ Runtime Library Runtime Error!Program:xxxxx.exe R6034An application has made an attempt to load the C runtime library incorrectly.Please contact the application's support team for more information. Detailed descriptions： Environment：　　　winxp,Mingw4.7+MSYS,Library：　　　wxwidgets2.8 static compile (called in gui code) python27 python27.dll (called in gui code) installed version boost.python static compile (called in gui code) boost.python static compile (called in custom module) libevent2.019 static compile (called in custom module) I can be successful,called only python in C++ or called custom module in python. What should I do to solve the problem?

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