July 2014 - Boost-users - lists.boost.org

How to judge matched rule when looping with sregex_token_iterator in boost.xpressive?
by Li Dong 03 Jul '14

03 Jul '14

Dear all, I would like to use boost.xpressive to parse some string like “a+b:c”, and I wrote the following snippet: sregex reOp = as_xpr('+') | '-' | '*' | '/'; sregex reDelim = as_xpr(':'); sregex reField = +_w; sregex reSimpleToken = reOp | reDelim | reField; string str = "a+b:c"; sregex_token_iterator cur(str.begin(), str.end(), reSimpleToken), end; for (; cur != end; ++cur) { cout << *cur << endl; } which will print: a + b : c but I would also want to know which rule is matched for the sequent operations, for example ‘a’, ‘b’ and ‘c' are matched by reField, and ‘+’ is matched by ‘reOp’. I am very new to boost.xpressive, so if this is not the good way, correct me please. Any help is appreciated! Best, Li

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Program Options - options dependencies
by Angelo Mondaini 02 Jul '14

02 Jul '14

Dear all, I am using the Program Options and I would like to know if I can add options dependencies through the lib. For example, consider a "test" program that has a flag "--has-dependencies" that needs a flag "--dependency" and a flag "--no-depenencies". It would run like this: $./test --no-dependencies Program running... $./test --has-dependencies Error! Flag "--dependency" is needed! $./test --has-dependencies --dependency Program running... PS: I know I can use something like this, but I would like to know if there is a better option: if ( vm.count("--has-dependencies") ) if ( vm.count("--dependency") ) //do something... else //trow an error

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Program Options not saving the values
by Angelo Mondaini 02 Jul '14

02 Jul '14

Dear all, I am having a problem with the Program Options lib. I am using Archlinux and boost-libs 1.55.0-6. Consider the simple code: #include "boost/program_options.hpp" #include <iostream> #include <string> int main(int argc, char** argv) { int add(5); namespace po = boost::program_options; po::options_description desc("Options"); desc.add_options() ("help", "Print help messages") ("add",po::value<int>(&add)->required(), "additional options") ("like", "this"); po::variables_map vm; po::store(po::parse_command_line(argc, argv, desc), vm); if ( vm.count("help") ) { std::cout << "Basic Command Line Parameter App" << std::endl << desc << std::endl; return 1; } std::cout << "var: " << add << std::endl; std::cout << "vm: " << vm["add"].as<int>() << std::endl; po::notify(vm); return 1; } Compiling and running: $ g++ program_options.cpp -lboost_program_options $ ./a.out --add 4 var: 5 vm: 4 Why the value of the variable "add" is not receiving 4? Thanks for any help.

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[ANN] CppCon 2014 program available
by Boris Kolpackov 02 Jul '14

02 Jul '14

The CppCon 2014 Program is now available with talk titles, abstracts, and speakers: http://cppcon.org/conference-program/ The program contains over 100 one-hour sessions by over 70 speakers including plenary sessions by Scott Meyers and Herb Sutter, as well as the keynotes by C++ creator Bjarne Stroustrup on Keeping Simple Things Simple and Mark Maimone on using C++ on Mars: Incorporating C++ into Mars Rover Flight Software. We have also extended the Early Bird deadline to July 9 so you have a week to study the program and still get the Early Bird rate. Hope to see you in Bellevue! Boris

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Why does async_connect() call listen()?
by Soren Dreijer 01 Jul '14

01 Jul '14

Hi there, By coincidence, I ended up looking at a stack trace where my application calls async_connect() on a asio::ip::tcp::socket. Two things took me by surprise: 1. Asio calls listen() under the hood. Why does it do that when I'm just trying to make an outbound TCP connection? 2. If the listen() call above is indeed required, why does it happen on the same thread where I call async_connect()? I thought the point of the method was to defer the work to the reactor? (For what it's worth, I've had a case on a customer's machine where the call to listen() would hang for 30 seconds before returning -- probably because of a bad firewall -- causing my entire app to hang since the code assumes async_connect() is indeed async.) I've included the full stack trace below. Thanks, Soren 0:000> k ChildEBP RetAddr 0117db50 0f681c65 WS2_32!listen 0117db70 0f691013 EvoClr!boost::asio::detail::socket_ops::listen+0x35 [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\detail\impl\socket_ops.ipp @ 658] 0117dbd8 0f690e9f EvoClr!boost::asio::detail::socket_select_interrupter::open_descriptors+0x163 [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\detail\impl\socket_select_interrupter.ipp @ 78] 0117dbe4 0f690cc0 EvoClr!boost::asio::detail::socket_select_interrupter::socket_select_interrupter+0xf [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\detail\impl\socket_select_interrupter.ipp @ 42] 0117dc1c 0f690c1e EvoClr!boost::asio::detail::select_reactor::select_reactor+0x70 [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\detail\impl\select_reactor.ipp @ 48] 0117dc44 0f17837e EvoClr!boost::asio::detail::service_registry::create<boost::asio::detail::select_reactor>+0x4e [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\detail\impl\service_registry.hpp @ 81] 0117dc80 0f6909e9 EvoClr!boost::asio::detail::service_registry::do_use_service+0x9e [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\detail\impl\service_registry.ipp @ 123] 0117dca0 0f6908ee EvoClr!boost::asio::detail::service_registry::use_service<boost::asio::detail::select_reactor>+0x39 [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\detail\impl\service_registry.hpp @ 49] 0117dca8 0f68fab0 EvoClr!boost::asio::use_service<boost::asio::detail::select_reactor>+0xe [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\impl\io_service.hpp @ 34] 0117dcbc 0f68f731 EvoClr!boost::asio::detail::win_iocp_socket_service_base::get_reactor+0x30 [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\detail\impl\win_iocp_socket_service_base.ipp @ 620] 0117dce4 0f68f6f1 EvoClr!boost::asio::detail::win_iocp_socket_service_base::start_connect_op+0x11 [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\detail\impl\win_iocp_socket_service_base.ipp @ 550] 0117dd28 0f68ed22 EvoClr!boost::asio::detail::win_iocp_socket_service<boost::asio::ip::tcp>::async_connect<boost::_bi::bind_t<void,boost::_mfi::mf1<void,Swift::BoostConnection,boost::system::error_code const &>,boost::_bi::list2<boost::_bi::value<boost::shared_ptr<Swift::BoostConnection> >,boost::arg<1> > > >+0xc1 [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\detail\win_iocp_socket_service.hpp @ 515] 0117dd68 0f68c41a EvoClr!boost::asio::stream_socket_service<boost::asio::ip::tcp>::async_connect<boost::_bi::bind_t<void,boost::_mfi::mf1<void,Swift::BoostConnection,boost::system::error_code const &>,boost::_bi::list2<boost::_bi::value<boost::shared_ptr<Swift::BoostConnection> >,boost::arg<1> > > >+0x52 [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\stream_socket_service.hpp @ 234] 0117ddec 0f68a32e EvoClr!boost::asio::basic_socket<boost::asio::ip::tcp,boost::asio::stream_socket_service<boost::asio::ip::tcp> >::async_connect<boost::_bi::bind_t<void,boost::_mfi::mf1<void,Swift::BoostConnection,boost::system::error_code const &>,boost::_bi::list2<boost::_bi::value<boost::shared_ptr<Swift::BoostConnection> >,boost::arg<1> > > >+0x11a [c:\private\src\vendor\boost_1_55_0_sdk\include\boost\asio\basic_socket.hpp @ 779] 0117de9c 0f210146 EvoClr!Swift::BoostConnection::connect+0x11e [c:\private\src\vendor\swift\swiften\network\boostconnection.cpp @ 70]

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[serialization] avoid nvp for wrapper class
by dariomt＠gmail.com 01 Jul '14

01 Jul '14

Hi list, How do I tell Boost.Serialization to serialize a wrapper as the primitive type, without requiring an nvp wrapper? I specifically don't want an extra level in the xml output. Example: given BOOST_STRONG_TYPEDEF(int, myInt); I'd like myInt to be serialized as an int. Thanks!

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[atomic] ThreadSanitizer reports a data race when using the code from "reference counting" example
by Adam Romanek 01 Jul '14

01 Jul '14

Hi Boosters! I'd like to draw your attention to an issue with Boost.Atomic that I encountered when using ThreadSanitizer. The problem is that when using the code shown in "reference counting" example [1] from the docs, the ThreadSanitizer reports a data race. Everything is described in detail in a StackOverflow thread [2] so I don't want to repeat all that here. Please help me determine whether it's a false positive, an issue in Boost.Atomic or a wrong usage of the code. Additionally, I don't understand this: Write of size 1 at 0x7d040000f7f0 by thread T2: #0 operator delete(void*) <null>:0 (a.out+0x00000004738b) What kind of write does ThreadSanitizer might refer to? WBR, Adam Romanek [1] http://www.boost.org/doc/libs/1_55_0/doc/html/atomic/usage_examples.html#bo… [2] http://stackoverflow.com/questions/24446561/threadsanitizer-reports-data-ra…

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Intel 14.0.1 error with boost::bind
by Aniket Pugaonkar 01 Jul '14

01 Jul '14

Hi, I am using a test program for compiling a boost::bind in Intel MIC(Xeom Phi). Here are the details of the code and platform on which it is compiled. I am using thread building blocks in my code, but the following code does not contain any TBB threads. The errors in my test code below and original code are same. Compiler : Intel 13.0.1 / intel 14.0.1 SP1 Update 3 (latest from intel composer XE trial version) I am using our lab's compiler installed on a cluster. The TBB is installed in my home directory. boost 1.55 is also installed in my home location. Compiled for MIC: icpc -mmic -L/home/aniketnp/tbb42_20140122oss/lib/mic -std=c++11 -I/home/aniketnp/boost_1_55_0 -I/home/aniketnp/tbb42_20140122oss/include test.cpp Scenario: a functor takes 2 arguments in its operator()() by using a boost::bind() method. The operator()() method contains a function which uses comparisons ( < or > ) using if-else logic. The error pops up here. Here is the following code. #include <iostream> #include <boost/bind.hpp> using namespace std; struct Info_t { int start; int end; Info_t(int s=0,int e=0) : start(s), end(e) { } }; template <typename T, typename time> void process_info(const T& info1, const T& info2, const time& t) { //the below gives compiler error * if ((info1.start < info2.end) && (info2.end > info1.end) && (info1.end < info2.start) )* std::cout << "yess error with mic" << std::endl; //the below if works fine if ((info1.start < info2.end) && (info2.end > info1.end)) std::cout << "no error at all" << std::endl; } template<typename Time> struct my_functor { public: my_functor() { } my_functor(Time& time_) : time(time_) { } typedef void result_type; template<typename info_t> void operator()(const info_t& info1, const info_t& info2) { const auto& i1 = info1; const auto& i2 = info2; process_info<info_t, Time> (i1,i2, time); } private: Time& time; }; int main() { Info_t i1(10,2); Info_t i2(2,10); int t = 1; auto func = boost::bind( my_functor<int>(t), _1, _2 ); func(i1,i2); return 0; } test.cpp(16): error: expression must have a constant value if ((info1.start < info2.end) && (info2.end > info1.end) && (info1.end < info2.start) ) ^ detected during: instantiation of "void my_functor<Time>::operator()(const info_t &, const info_t &) [with Time=int, info_t=Info_t]" at line 313 of "/home/aniketnp/boost_1_55_0/boost/bind/bind.hpp" instantiation of "void boost::_bi::list2<A1, A2>::operator()(boost::_bi::type<void>, F &, A &, int) [with A1=boost::arg<1>, A2=boost::arg<2>, F=my_functor<int>, A=boost::_bi::list2<Info_t &, Info_t &>]" at line 61 of "/home/aniketnp/boost_1_55_0/boost/bind/bind_template.hpp" instantiation of "boost::_bi::bind_t<R, F, L>::result_type boost::_bi::bind_t<R, F, L>::operator()(A1 &, A2 &) [with R=boost::_bi::unspecified, F=my_functor<int>, L=boost::_bi::list2<boost::arg<1>, boost::arg<2>>, A1=Info_t, A2=Info_t]" at line 48 test.cpp(16): error: this operator is not allowed in a template argument expression if ((info1.start < info2.end) && (info2.end > info1.end) && (info1.end < info2.start) ) ^ detected during: instantiation of "void my_functor<Time>::operator()(const info_t &, const info_t &) [with Time=int, info_t=Info_t]" at line 313 of "/home/aniketnp/boost_1_55_0/boost/bind/bind.hpp" instantiation of "void boost::_bi::list2<A1, A2>::operator()(boost::_bi::type<void>, F &, A &, int) [with A1=boost::arg<1>, A2=boost::arg<2>, F=my_functor<int>, A=boost::_bi::list2<Info_t &, Info_t &>]" at line 61 of "/home/aniketnp/boost_1_55_0/boost/bind/bind_template.hpp" instantiation of "boost::_bi::bind_t<R, F, L>::result_type boost::_bi::bind_t<R, F, L>::operator()(A1 &, A2 &) [with R=boost::_bi::unspecified, F=my_functor<int>, L=boost::_bi::list2<boost::arg<1>, boost::arg<2>>, A1=Info_t, A2=Info_t]" at line 48 test.cpp(16): error: expected a ">" if ((info1.start < info2.end) && (info2.end > info1.end) && (info1.end < info2.start) ) ^ detected during: instantiation of "void my_functor<Time>::operator()(const info_t &, const info_t &) [with Time=int, info_t=Info_t]" at line 313 of "/home/aniketnp/boost_1_55_0/boost/bind/bind.hpp" instantiation of "void boost::_bi::list2<A1, A2>::operator()(boost::_bi::type<void>, F &, A &, int) [with A1=boost::arg<1>, A2=boost::arg<2>, F=my_functor<int>, A=boost::_bi::list2<Info_t &, Info_t &>]" at line 61 of "/home/aniketnp/boost_1_55_0/boost/bind/bind_template.hpp" instantiation of "boost::_bi::bind_t<R, F, L>::result_type boost::_bi::bind_t<R, F, L>::operator()(A1 &, A2 &) [with R=boost::_bi::unspecified, F=my_functor<int>, L=boost::_bi::list2<boost::arg<1>, boost::arg<2>>, A1=Info_t, A2=Info_t]" at line 48 As a workaround, I try to do this, but same error if ((info2.start < info2.end) && (info2.end > info1.end) ) { if ( info1.end < info2.start) //do something } // error is propagated towards inner if loop test.cpp(17): error: expression must have a constant value if ( info1.end < info2.start) ^ detected during: instantiation of "void my_functor<Time>::operator()(const info_t &, const info_t &) [with Time=int, info_t=Info_t]" at line 313 of "/home/aniketnp/boost_1_55_0/boost/bind/bind.hpp" instantiation of "void boost::_bi::list2<A1, A2>::operator()(boost::_bi::type<void>, F &, A &, int) [with A1=boost::arg<1>, A2=boost::arg<2>, F=my_functor<int>, A=boost::_bi::list2<Info_t &, Info_t &>]" at line 61 of "/home/aniketnp/boost_1_55_0/boost/bind/bind_template.hpp" instantiation of "boost::_bi::bind_t<R, F, L>::result_type boost::_bi::bind_t<R, F, L>::operator()(A1 &, A2 &) [with R=boost::_bi::unspecified, F=my_functor<int>, L=boost::_bi::list2<boost::arg<1>, boost::arg<2>>, A1=Info_t, A2=Info_t]" at line 49 test.cpp(17): error: this operator is not allowed in a template argument expression (rest error is the same) ------------------------------------------------------------------------------------------------- Now, if I compile it without " -mmic " flag, then there is no compiler errors. I compile with this : icpc -L/home/aniketnp/tbb42_20140122oss/lib/intel64/gcc4.4 -std=c++11 -I/home/aniketnp/boost_1_55_0 -I/home/aniketnp/tbb42_20140122oss/include test.cpp I dont get any error. It compiles and runs fine. Any thoughts ? Please let me know. -- Thanks and regards, Aniket Pugaonkar

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