January 2010 - Boost-users - lists.preview.boost.org

Help with shared_ptr and template
by Mario Chacon 10 Sep '10

10 Sep '10

Hello: I have this problem and I do not how to fix it, I know I cannot write template typedefs, its a limitiation of the C++ syntax, right? or I'm wrong? I saw that the best way is to wrap your typedefs in a struct, which can be templated, but I'm still stack with problems. The best way to explain it's with an example: #include <cstdlib> #include <iostream> #include <boost/shared_ptr.hpp> template< typename tvalue > class CValue { public: CValue( tvalue value ) : value_(value) {}; private: tvalue value_; }; template< typename tvalue > struct Type{ typedef boost::shared_ptr< CValue< tvalue > > pValue; }; int main(int argc, char *argv[]) { Type<bool>::pValue a; return EXIT_SUCCESS; } How can I create a shared_ptr for the template class "CVALUE"?? Please I do not know what else I can prove... :( Thank you.. Mario.. Salu2...

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Multithread event handling
by Alessandro Bellina 21 Mar '10

21 Mar '10

Hello boost, Traditionally, I think of services as having a thread pool or manually managed threads to handle requests and produce responses. I have been looking at boost::asio and tbb as an alternative to this in order to take advantage of multiple cores. Also, I think that implementing an event handler with asio or tbb should provide better performance over a threadpool. Do you have any suggestions? So far, I have implemented an example using tbb::task_group and spawned tasks. This yielded full CPU utilization, but since these are very short lived tasks, the task creation overhead took over. Using io_service, it seems to be as easy as posting to the service, and running it among different threads. Would this be the correct approach for my case? Can somebody share their experiences on libraries or patterns used to implement an event handling mechanism? Thanks, Alessandro

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Link issue with condition_variable
by Bradley W. Settlemyer 19 Mar '10

19 Mar '10

Hello, I'm using boost for the first time and I'm struggling to link my program. I've added libboost_pthread-mt to the link link (which got most of the symbols), but I still can't seem to get the symbols for the condition variables. The issue could be with the code, as I find the lock-mutex-condition_variable interactions to be very confusing, but it does appear to be a link issue. Consider the following error message emitted during link command: mpicxx <objects> -D_FILE_OFFSET_BITS=64 -L/lib64 -lfuse -lrt -ldl -lboost_thread-mt -lpthread -o aio_benchmark src/aio/thread_pool_adaptive_writer.o: In function `aio::ThreadPoolWriter::Write(aio::File*, std::vector<int, std::allocator<int> >, void*, unsigned long)': /home/bws/sandbox/aiofs/src/aio/thread_pool_writer.cc:59: undefined reference to `boost::condition_variable::notify_all()' /home/bws/sandbox/aiofs/src/aio/thread_pool_writer.cc:63: undefined reference to `boost::condition_variable::wait(boost::unique_lock<boost::mutex>&)' src/aio/thread_pool_writer.o: In function `aio::ThreadPoolWriter::threadWait()': /home/bws/sandbox/aiofs/src/aio/thread_pool_writer.cc:76: undefined reference to `boost::condition_variable::wait(boost::unique_lock<boost::mutex>&)' /home/bws/sandbox/aiofs/src/aio/thread_pool_writer.cc:110: undefined reference to `boost::condition_variable::notify_one()' Is condition variable in a different library? I am using the boost stuff distributed with Fedora 11: boost-1.37.0-7.fc11.x86_64 boost-devel-1.37.0-7.fc11.x86_64 Cheers, Brad

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Syntax error when using BOOST_CHECK_PREDICATE
by Andrew J. Leer 24 Feb '10

24 Feb '10

Reading this article: http://www.ibm.com/developerworks/aix/library/au-ctools1_boost/?S_TACT=105A… I'm using Boost 1.40.0 and Visual Studio 2005 with Visual C++ 8.0. I've entered Listing 14 with a few additional lines of logging code: #include "stdafx.h" #define BOOST_TEST_MODULE example #include <boost/test/included/unit_test.hpp> std::list<int> user_defined_func( ) { std::cout << "BEGIN: user_defined_func" << std::endl; std::list<int> l; l.push_back(8); l.push_back(0); std::cout << "END: user_defined_func" << std::endl; return l; } bool validate_list(std::list<int> &L1) { std::cout << "BEGIN: validate_list" << std::endl; std::list<int>::iterator it1 = L1.begin(); for(; it1 != L1.end(); ++it1) { if(*it1<= 1){ std::cout << "Validation failed because an item in the list was less than or equal to 1." << std::endl; std::cout << "END: validate_list" << std::endl; return false; } } std::cout << "Test passed because all of the items in the list were greater than or equal to 1" << std::endl; std::cout << "END: validate_list" << std::endl; return true; } BOOST_AUTO_TEST_SUITE( test ) BOOST_AUTO_TEST_CASE( test ) { std::list<int>& list1 = user_defined_func(); BOOST_CHECK_PREDICATE( validate_list, list1 ); } BOOST_AUTO_TEST_SUITE_END() Now when I go to compile this, it ends up giving me an error: 1>------ Build started: Project: UnitTestTests, Configuration: Debug Win32 ------ 1>Compiling... 1>UnitTestTests.cpp 1>c:\program files (x86)\boost\boost_1_40\boost\test\impl\execution_monitor.ipp(904) : warning C4535: calling _set_se_translator() requires /EHa 1>c:\program files (x86)\boost\boost_1_40\boost\test\utils\runtime\config.hpp(90) : warning C4996: 'putenv': The POSIX name for this item is deprecated. Instead, use the ISO C++ conformant name: _putenv. See online help for details. 1> c:\program files (x86)\microsoft visual studio 8\vc\include\stdlib.h(900) : see declaration of 'putenv' 1>c:\program files (x86)\boost\boost_1_40\boost\test\utils\runtime\cla\char_parameter.ipp(36) : warning C4244: 'argument' : conversion from 'boost::rtti::id_t' to 'const int', possible loss of data 1>c:\program files (x86)\boost\boost_1_40\boost\test\utils\runtime\cla\named_parameter.ipp(41) : warning C4244: 'argument' : conversion from 'boost::rtti::id_t' to 'const int', possible loss of data 1>c:\program files (x86)\boost\boost_1_40\boost\test\utils\runtime\env\environment.ipp(82) : warning C4996: 'getenv': This function or variable may be unsafe. Consider using _dupenv_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details. 1> c:\program files (x86)\microsoft visual studio 8\vc\include\stdlib.h(483) : see declaration of 'getenv' 1>c:\users\andy\documents\visual studio 2005\projects\unittesttests\unittesttests\unittesttests.cpp(45) : error C2146: syntax error : missing ')' before identifier 'BOOST_PP_IIF_BOOST_PP_BOOL_0' 1>c:\users\andy\documents\visual studio 2005\projects\unittesttests\unittesttests\unittesttests.cpp(45) : error C2780: 'bool boost::test_tools::tt_detail::check_frwd(Pred,const boost::unit_test::lazy_ostream &,boost::test_tools::const_string,size_t,boost::test_tools::tt_detail::tool_level,boost::test_tools::tt_detail::check_type,const Arg0 &,const char *,const Arg1 &,const char *,const Arg2 &,const char *,const Arg3 &,const char *,const Arg4 &,const char *)' : expects 16 arguments - 6 provided 1> c:\program files (x86)\boost\boost_1_40\boost\test\test_tools.hpp(523) : see declaration of 'boost::test_tools::tt_detail::check_frwd' 1>c:\users\andy\documents\visual studio 2005\projects\unittesttests\unittesttests\unittesttests.cpp(45) : error C2780: 'bool boost::test_tools::tt_detail::check_frwd(Pred,const boost::unit_test::lazy_ostream &,boost::test_tools::const_string,size_t,boost::test_tools::tt_detail::tool_level,boost::test_tools::tt_detail::check_type,const Arg0 &,const char *,const Arg1 &,const char *,const Arg2 &,const char *,const Arg3 &,const char *)' : expects 14 arguments - 6 provided 1> c:\program files (x86)\boost\boost_1_40\boost\test\test_tools.hpp(523) : see declaration of 'boost::test_tools::tt_detail::check_frwd' 1>c:\users\andy\documents\visual studio 2005\projects\unittesttests\unittesttests\unittesttests.cpp(45) : error C2780: 'bool boost::test_tools::tt_detail::check_frwd(Pred,const boost::unit_test::lazy_ostream &,boost::test_tools::const_string,size_t,boost::test_tools::tt_detail::tool_level,boost::test_tools::tt_detail::check_type,const Arg0 &,const char *,const Arg1 &,const char *,const Arg2 &,const char *)' : expects 12 arguments - 6 provided 1> c:\program files (x86)\boost\boost_1_40\boost\test\test_tools.hpp(523) : see declaration of 'boost::test_tools::tt_detail::check_frwd' 1>c:\users\andy\documents\visual studio 2005\projects\unittesttests\unittesttests\unittesttests.cpp(45) : error C2780: 'bool boost::test_tools::tt_detail::check_frwd(Pred,const boost::unit_test::lazy_ostream &,boost::test_tools::const_string,size_t,boost::test_tools::tt_detail::tool_level,boost::test_tools::tt_detail::check_type,const Arg0 &,const char *,const Arg1 &,const char *)' : expects 10 arguments - 6 provided 1> c:\program files (x86)\boost\boost_1_40\boost\test\test_tools.hpp(523) : see declaration of 'boost::test_tools::tt_detail::check_frwd' 1>c:\users\andy\documents\visual studio 2005\projects\unittesttests\unittesttests\unittesttests.cpp(45) : error C2780: 'bool boost::test_tools::tt_detail::check_frwd(Pred,const boost::unit_test::lazy_ostream &,boost::test_tools::const_string,size_t,boost::test_tools::tt_detail::tool_level,boost::test_tools::tt_detail::check_type,const Arg0 &,const char *)' : expects 8 arguments - 6 provided 1> c:\program files (x86)\boost\boost_1_40\boost\test\test_tools.hpp(523) : see declaration of 'boost::test_tools::tt_detail::check_frwd' 1>c:\users\andy\documents\visual studio 2005\projects\unittesttests\unittesttests\unittesttests.cpp(45) : error C2059: syntax error : ')' 1>Build log was saved at "file://c:\Users\andy\Documents\Visual Studio 2005\Projects\UnitTestTests\UnitTestTests\Debug\BuildLog.htm" It seems to have some real problems with the BOOST_CHECK_PREDICATE macro why is this? Thank you, Andrew J. Leer 1>UnitTestTests - 7 error(s), 5 warning(s) ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

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Transfering the process state to another process
by Lloyd 18 Feb '10

18 Feb '10

Hi, We want to have a program which cannot be terminated by the user (even admin). I think the only way to do this is to write a watchdog process. So there will be a master and a slave process, the master will be the active process, and the slave keep on watching the master. I case if the master is terminated, the slave become master and initiates a new slave process. But we need to transfer (or share) the process state of "old master" with the "new master" (So that the new master can continue form where the old master has stopped). Is this possible with shared memory? Or is there is a better way? Thanks, Lloyd ______________________________________ Scanned and protected by Email scanner

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[1.35.0][OSX][iostreams] Exception thrown with utf8 filename
by Christophe Radondy 17 Feb '10

17 Feb '10

Hi, I try to do a cross-platform source code and I have this code. I compiled boost 1.35 in universal binaries on Mac OS 10.5.4 with intel platform (IMAC core 2 duo 3Ghz) The same code works on linux (Ubuntu 8.0.4 and debian) and windows platforms but on Mac OS 10.5 I have an exception in boost's libraries. We compile on universal binaries with -fexceptions options of g++ 4.0.1 (Apple). This is my code: <code> boost::filesystem::wpath unicode(L"abcdef\u0110"); boost::filesystem::ofstream file(unicode.string()); // throws Invalid Argument on Mac file << "abcdef" << endl; file.close(); <endcode/> If I do this, it works: <code> boost::filesystem::path utf8("abcdef\xC4\x90"); // \xC4\x90 == \u0110 boost::filesystem::ofstream file(utf8.string()); // works ok file << "abcdef" << endl; file.close(); <endcode/> When the ofstream is created, this function is executed and crashes when I use Unicode parameters : <code> unicode.external_file_string(); // throws uncaught exception of type boost::filesystem::basic_filesystem_error<boost::filesystem::basic_path<std::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> >, boost::filesystem::wpath_traits> > - boost::filesystem::wpath::to_external conversion error: Invalid argument <endcode/> Do you have any idea? Is this a known bug? Did I miss a setting? Thanks for your help. Regards, Christophe.

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Embedding boost in a given project
by joel falcou 17 Feb '10

17 Feb '10

In order to satisfy various users request and to limit potential whining about implicit dependencies on boost, I've started lookign at how to embed boost components into my own tools. What are the usual way to do that ? I pondered working with a given version (say 1.42) in which I could add w/e patches and fixed from the trunk along with my own custom patches. I then use BCP to extract sub boost compoennt to my release package. Now, the final funny thing is that, for various reason, we don't use bjam atm for our own product build. I guess adding a makefile fuel like dependency: bjam --with-xxxx is enough for example ? Any experience to be shared on that topic ? -- ___________________________________________ Joel Falcou - Assistant Professor PARALL Team - LRI - Universite Paris Sud XI Tel : (+33)1 69 15 66 35

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[Boost Graph] Two-graphs common spanning tree problem: generic algorithm (with concept checking, of course)
by Michele Caini 15 Feb '10

15 Feb '10

Hi all, my name is Michele Caini, I write from Italy, Florence, and this is my first mail on this list. I'd like to propose a new generic implementation of the two-graphs common three algorithm, proposed first by Grimbleby and then modified by Schach, that made a revolution on the first idea basing his algorithm on the solution for the single spanning three problem proposed and developed by Mint, Read and Tarjan. This algorithm is mainly used in symbolic circuit analysis, and I develop a generic solution for my symbolic solutor: QSapecNG, Qt-based frontend for symbolic circuit solution. If Boost Graph library mantainers are interested on publishing this algorithm with the next release of library, I'm happy to submit it, and to work on to optimize the code. Thanks to all, Michele ps: sorry for my English. :-)

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generate structs with all combinations of members from a given struct
by Hicham Mouline 14 Feb '10

14 Feb '10

Hello, struct params { double field1; double field2; double field3; double fiedl4; }; I would like to generate all the types that hold any combination of the members of params. struct params_field1 { double field1; }; struct params_field2 { double field2; }; struct params_field3 { double field3; }; struct params_field4 { double field4; }; struct params_field1_field2 { double field1; double field2; }; struct params_field1_field3 { double field1; double field3; }; struct params_field1_field4 { double field1; double field4; }; struct params_field2_field3 { double field2; double field3; }; struct params_field2_field4 { double field2; double field4; }; struct params_field3_field4 { double field3; double field4; }; struct params_field1_field2_field3 { double field1; double field2; double field3; }; struct params_field1_field2_field4 { double field1; double field2; double field4; }; struct params_field1_field3_field4 { double field1; double field3; double field4; }; struct params_field2_field3_field4 { double field2; double field3; double field4; }; struct params_field1_field2_field3_field4 { double field1; double field2; double field3; double field4; }; There are 15 of these, which is 2^4 -1, where 4 is the number of members in params. Assuming params is adapted as a fusion sequence, this looks doable with PP? Should I be looking at BOOST_PP_LIST_FOLD_xxx macros? regards,

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[Boost] Is this library availble for 64 bit?
by Jaiswal, Usha [OS-IE] 11 Feb '10

11 Feb '10

Is there any version of Boost for 64 bit.

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