December 2013 - Boost-users

[Asio] io_service(std::size_t concurrency_hint) constructor
by maks 16 Dec '13

16 Dec '13

Hello All In what cases using "io_service(std::size_t concurrency_hint)" ctor is more effective? 1. Use multiple threads - multiple io_service 2. Use multiple threads on one io_service object Thanks.

2 1

Delegating to boost::function with arbitrary signature
by Alexander Lamaison 16 Dec '13

16 Dec '13

I've asked this question on Stack Overflow but not found a solution yet: http://stackoverflow.com/q/20578575/67013. It's Boost.Function/MPL-related so I'll ask here too. I'm trying to create something like a `boost::function`, but with an extra 'smart handle' tucked inside, which controls the lifetime of a resource the functions needs to execute correctly. If I didn't need the function signature to be completely generic, this would be easy. I would just create a functor with the correct signature, and keep a `boost::function` and the handle as members. However, I do need generic signatures. The code below is as close as I've got but gets a compile error, presumably, because I'm not able to unpack a list of arguments like this: template<typename Signature> class library_function { public: library_function( library_handle handle, boost::function<result_type(arg1_type, arg2_type)> function) : m_handle(handle), m_function(function) {} typename result_type operator()(arg1_type arg1, arg2_type arg2) { return m_function(arg1, arg2); } // I don't think I can declare the 'params' like this ... typename boost::function_types::result_type<Signature>::type operator()( boost::function_types::parameter_types<Signature> params) { return m_function(params); // ... nor unpack them like this } private: boost::function<Signature> m_function; library_handle m_library; }; I think `params` is an MPL list, so what I've actually done is declare a call operator with a single MPL-list parameter. My MPL-foo is not good. Is there a way to convert the list to a legal definition of multiple function paramters? A suggested solution on SO is to use `boost::bind`, but I still don't see how to bind an arbitrary number of arguments. All advice greatly appreciated. Alex -- Swish - Easy SFTP for Windows Explorer (http://www.swish-sftp.org)

4 9

[asio][openssl]Boost SSL with Visual Studio 2012 and OpenSSL
by lx 16 Dec '13

16 Dec '13

hello: I use : windows 7 64bit, vs 2012 , boost 1.5.4 , Win64OpenSSL_Light-1_0_1e. the codes is: ######################## #include <boost/asio.hpp> #include <boost/asio/ssl.hpp> ######################## When I complie it, the wrong messages is: ########################################## 1>gtest.obj : error LNK2019: unresolved external symbol _CRYPTO_cleanup_all_ex_data referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::~do_init(void)" (??1do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>gtest.obj : error LNK2019: unresolved external symbol _CRYPTO_num_locks referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::do_init(void)" (??0do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>gtest.obj : error LNK2019: unresolved external symbol _CRYPTO_set_locking_callback referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::do_init(void)" (??0do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>gtest.obj : error LNK2019: unresolved external symbol _CRYPTO_set_id_callback referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::do_init(void)" (??0do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>gtest.obj : error LNK2019: unresolved external symbol _CONF_modules_unload referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::~do_init(void)" (??1do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>gtest.obj : error LNK2019: unresolved external symbol _OPENSSL_add_all_algorithms_noconf referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::do_init(void)" (??0do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>gtest.obj : error LNK2019: unresolved external symbol _EVP_cleanup referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::~do_init(void)" (??1do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>gtest.obj : error LNK2019: unresolved external symbol _SSL_load_error_strings referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::do_init(void)" (??0do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>gtest.obj : error LNK2019: unresolved external symbol _SSL_library_init referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::do_init(void)" (??0do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>gtest.obj : error LNK2019: unresolved external symbol _ERR_reason_error_string referenced in function "public: virtual class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > __thiscall boost::asio::error::detail::ssl_category::message(int)const " (?message@ssl_category@detail@error@asio@boost@@UBE?AV?$basic_string@DU ?$char_traits@D@std@@V?$allocator@D@2@@std@@H@Z) 1>gtest.obj : error LNK2019: unresolved external symbol _ERR_free_strings referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::~do_init(void)" (??1do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>gtest.obj : error LNK2019: unresolved external symbol _ERR_remove_state referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::~do_init(void)" (??1do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>gtest.obj : error LNK2019: unresolved external symbol _ENGINE_cleanup referenced in function "public: __thiscall boost::asio::ssl::detail::openssl_init_base::do_init::~do_init(void)" (??1do_init@openssl_init_base@detail@ssl@asio@boost@@QAE@XZ) 1>D:\program\gdnscenter-1.12.2\src\Debug\gtest.exe : fatal error LNK1120: 13 unresolved externals ========== Build: 0 succeeded, 1 failed, 3 up-to-date, 0 skipped ========== ########################################## the simiar question in stackoverflow : http://stackoverflow.com/questions/9357751/boost-ssl-with-visual-studio-201… . I use the openssl win64. So, Maybe a bug in asio? Thank you.

2 1

Crash in VS2013, bug in compiler, boost or my code ? (flyweight, variant and initializer list)
by Olivier Tristan 16 Dec '13

16 Dec '13

Hello Boost users, Using the following sample code I have some crash in VS2013 but it works fine in LLVM on OSX Is this is a mistake on my side or an issue elsewhere ? #include <string> #include <cstdint> #include <vector> #include <boost/flyweight/flyweight.hpp> #include <boost/flyweight/no_tracking.hpp> #include <boost/flyweight/static_holder.hpp> #include <boost/flyweight/set_factory.hpp> #include <boost/flyweight/simple_locking.hpp> #include <boost/variant.hpp> typedef boost::flyweights::flyweight< std::string, boost::flyweights::no_tracking, boost::flyweights::set_factory<>, boost::flyweights::static_holder, boost::flyweights::simple_locking > string_flyweight; typedef boost::variant< bool, double, string_flyweight > Variant; int main(void) { std::vector<Variant> v = { 1., true, string_flyweight("toto") }; return 0; } Thanks, -- Olivier TRISTAN uvi.net

5 8

library choice
by Mihir Thakkar 15 Dec '13

15 Dec '13

I am new to boost. I would like to contribute to development. I looked through the libraries and got confused from where to start understanding and reading such a large codebase. Is it that all the libraries are independent of each other and I've to look at only those which I want to work with? Please guide me on how to begin understanding. Thanks! :)

3 2

Boost Geometry - RTree with 1D Segments
by Adam Baxter 14 Dec '13

14 Dec '13

Hello all, I've been using boost::icl for interval searching. So far it's been working great. I am using it for closed interval searches for chemical masses. Unfortunately, I've reached a point where I've too much data, I think. The use of sets has started to kill my memory usage. I'd like to switch over to Boost::Geometry, but there's precious little about indexing 1D segments (I don't even mind 2D segments). Can someone point me in the right direction? Thanks! Adam

1 0

Threading question
by Davies, John 13 Dec '13

13 Dec '13

I have the following code and it terminates as expected. When I call the destructor it interrupts the thread. But if I change the this_thread::sleep to this_thread::yield the join() never happens and the program hangs. I must be misunderstanding yield. But I really don't want a sleep if possible. Thanks, John MessageQueueHandler::~MessageQueueHandler() { // Terminate the thread pMessageQueueInputThread->interrupt(); pMessageQueueInputThread->join(); delete pMessageQueueInputThread; } void MessageQueueHandler::MessageQueueInputThread() { unsigned int receivedSize; unsigned int priority; char buffer[queueMaximumMessageSize]; boost::this_thread::interruption_enabled(); try { while(1) { // Process all messages in the queue while(inputMessageQueue->try_receive(buffer, queueMaximumMessageSize, receivedSize, priority)) { BaseMessage * msg = reinterpret_cast<BaseMessage*>(buffer); callbackTable->DispatchMessage(msg); boost::this_thread::interruption_point(); } // Give other threads a chance to run // This is also an interruption point boost::this_thread::sleep(boost::posix_time::millisec(50)); <==Here } } catch(boost::thread_interrupted const&) { return; } } ___________________________________ John Davies Contractor Home Respiratory Care Philips Home Healthcare Solutions 1740 Golden Mile Highway Monroeville, PA 15146 Email: john.davies(a)philips.com Fax: 724-387-4109 ________________________________ The information contained in this message may be confidential and legally protected under applicable law. The message is intended solely for the addressee(s). If you are not the intended recipient, you are hereby notified that any use, forwarding, dissemination, or reproduction of this message is strictly prohibited and may be unlawful. If you are not the intended recipient, please contact the sender by return e-mail and destroy all copies of the original message.

4 5

[Spirit/Qi/Phoenix] non compiling rules...
by Francois Mauger 12 Dec '13

12 Dec '13

Dear Boosters, The following code is one of my first attempts to use Spirit/Qi. For my education, I have tried 2 techniques to parse the simple "aaa=131;" string. The first one (Block A) compiles and seems to output the expected result. The second (B) does not compile with a huge massively templatized backtrace that I don't understand. What is the difference between using online rules and rule objects ? Is there a syntax error somewhere ? I'm afraid the documentation and example are rather terse about the syntax to be used here when coupling Qi and Phoenix... Many thanks for your help. best regards frc -- <pre> #include <iostream> #include <string> #include <vector> // - Boost/Spirit #include <boost/spirit/include/qi.hpp> #include <boost/spirit/include/phoenix_core.hpp> #include <boost/spirit/include/phoenix_operator.hpp> int main( int argc_, char * argv_[]) { int error_code = EXIT_SUCCESS; using boost::spirit::qi::double_; using boost::spirit::qi::string; using boost::spirit::qi::lit; using boost::spirit::qi::lexeme; using boost::spirit::qi::phrase_parse; using boost::spirit::qi::_1; using boost::spirit::qi::as_string; using boost::spirit::ascii::space; using boost::spirit::ascii::char_; using boost::phoenix::ref; { // Block A /// This compiles: std::string s = "aaa=131;"; std::cout << "s: '" << s << "'" << std::endl; std::string::iterator strbegin = s.begin(); std::vector<char> vkey; std::vector<char> vvalue; bool r = phrase_parse( strbegin, s.end(), (+(char_ - '='))[boost::phoenix::ref(vkey) = boost::spirit::qi::_1 ] >> '=' >> *space >> lexeme[+(char_ - ';')][boost::phoenix::ref(vvalue) = boost::spirit::qi::_1 ], space ); if (r) { std::string key(vkey.begin(), vkey.end()); std::string value(vvalue.begin(), vvalue.end()); std::cout << "key : '" << key << "'" << std::endl; std::cout << "value : '" << value << "'" << std::endl; } } { /// Block B /// This doesn't: std::string s = "aaa=131;"; std::cout << "s: '" << s << "'" << std::endl; std::string::iterator strbegin = s.begin(); std::vector<char> vkey; std::vector<char> vvalue; boost::spirit::qi::rule<std::string::iterator> key_rule = +(char_ - '='); boost::spirit::qi::rule<std::string::iterator> value_rule = lexeme[+(char_ - ';')]; bool r = phrase_parse( strbegin, s.end(), key_rule[boost::phoenix::ref(vkey) = boost::spirit::qi::_1 ] >> '=' >> *space >> value_rule[boost::phoenix::ref(vvalue) = boost::spirit::qi::_1 ], space ); if (r) { std::string key(vkey.begin(), vkey.end()); std::string value(vvalue.begin(), vvalue.end()); std::cout << "key : '" << key << "'" << std::endl; std::cout << "value : '" << value << "'" << std::endl; } } return error_code; } </pre> -- François Mauger

3 4

version control choice
by Mihir Thakkar 12 Dec '13

12 Dec '13

Hey all, I am using Ubuntu and Git. Would it be alright if I work on Git? Is everything available on Git repository as well?

2 1

slow exception handling
by XIN LI 12 Dec '13

12 Dec '13

Hi, In my code, I add some protection to catch the exception from boost like "catch (boost::archive::archive_exception& ex)", strangely, it slow exception handling, causing one of our tests to go from around 30 seconds to greater than 5 minutes. I did profiling and found "linear_searc_fdes" spent too much time when process exception now. Does anyone have similar experience, why this happen, and how to fix the problem? Thanks a lot! Best wishes, Andy Li

3 4

How do I build libraries with binaries using two versions of the same toolset
by Ted Byers 11 Dec '13

11 Dec '13

On my OpenSuse box, version 12.3, the default version of gcc is 4.7. I just successfully built gcc 4.8.2, with the binary names ending with 48 (so I have gcc48, g++48, &c.). So, I have two versions of gcc on this machine, and I believe I can use either by setting CC to the one or the other in my make files. Hence my problem. I have built boost 1.55.0 on my Ubuntu 12.04 box (but with the default names, so that gcc -v tells me that I am using gcc 4.8.2: the default version of gcc on that version of Ubuntu is 4.6, which is too old for me to consider). So, a basic build of the boost libraries is simple, and something I have done before. But I do not know how to build boost twice, once with gcc 4.7 and once with gcc 4.8.2, and have them installed in such a way as to ensure that the two builds do not clash and so that if I set CC to the one or the other version of gcc, the right build of boost will automagically be selected (it would be appreciated if someone who knows Gnu make better than I do could show me how to effect that in my makefiles). Obviously I am assuming that a single build of boost will not work with both compilers (is that assumption correct?). Unfortunately, I have not yet found anything in the documentation that talks about building boost with different versions of a given toolset on the same machine. Any help would be appreciated. Thanks Ted

2 3

[spirit::karma | variant] Nested Variants
by Aaron_Wright＠selinc.com 11 Dec '13

11 Dec '13

I am trying to use spirit::karma to generate a CSV file. I want to output a vector of variants. Unfortunately, I also want to add one more type to the variant; a string. So I was thinking I could nest variants. I can get this code to compile, but only the strings print out. What am I doing wrong? template< typename Iterator > class Generator : public boost::spirit::karma::grammar< Iterator, std::vector< boost::variant< std::string, boost::variant< bool, int > > >() > { public: Generator() : Generator::base_type(start) { using boost::spirit::karma::string; using boost::spirit::karma::bool_; using boost::spirit::karma::int_; using boost::spirit::karma::eol; start = (string | bool_ | int_) % Separator() << eol; } boost::spirit::karma::rule< Iterator, Csv_generator_input() > start; }; int main(int argc, char** argv) { std::vector< boost::variant< std::string, boost::variant< bool, int > > > values; values.push_back(std::string("Hello")); values.push_back(true); values.push_back(false); values.push_back(10); values.push_back(std::string("World")); std::string generated; std::back_insert_iterator< std::string > sink(generated); boost::spirit::karma::generate(sink, Generaator(), values); // generated == "Hello,World", Expected "Hello,true,false,10,World" return 0; } --- Aaron Wright

1 0

Problem using a filtered graph in the Ressource constrained shortest path user defined extension and dominance functions
by Berit Dangaard Brouer 11 Dec '13

11 Dec '13

Hi, In our use of the boost ressource constrained shortest path from Boost BGL, we define problem specific ressource extension and dominance function on a user defined graph type mcf_graph (source code is posted below) Our problem is the use of a filtered graph into the resource function. The forfeited edge filter stated in the code below, tries to remove some of the edges in order to speed up the algorithm. It seems that the resource and extension functions do not know how to deal with the filtered graph (I am guessing because they are not template functions), although the filtered graph contains the same Edge and Vertex definitions as the MCF graph, it is not typewise recognised as an mcf_graph, because it also contains the filter map. Is there any way I can work around this? I tried making the resource and extension functions into templates, but this is a problem because my edge bundled properties are problem specific. I would truly appreciate any suggestions as a filter is preferable to copying the graph. mcf_graph.h #ifndef MCF_GRAPH_HPP #define MCF_GRAPH_HPP #include <boost/config.hpp> #include <boost/graph/adjacency_list.hpp> #include <iostream> using namespace boost; using namespace std; struct Port { Port(int index=-1, int type=-1, int port_code=0, string UN="NN", string name="NN", int service_id=-1 ): m_index(index), m_type(type), m_port_code( port_code), UNLOCODE(UN), m_name(name), m_service_id(service_id) {} int m_index; int m_type;//0 port, 1 port call, 2 transhipment int m_port_code; string UNLOCODE; string m_name; int m_service_id; }; struct Edge { Edge( int id=-1, int type=-1, double weight=0.0, double cost=0.0, double dual_cost=0.0, double util=0.0, double cap=0.0, double r_cap=0.0, double tt=0.0 , int rot=-1) : m_idx(id), m_type(type), m_weight(weight) , m_cost(cost), m_dual_cost(dual_cost), m_utilization(util), m_capacity(cap), m_res_cap(r_cap), m_transittime(tt), m_rot(rot) {} unsigned int m_idx; int m_type;//0 is load edge, 1 is voyage edge, 2 forfeited edge (commodity link), 3 transhipment edge, 4 transhipment ring edge double m_weight; //distance double m_cost; //cost - only on load/unload/transhipment edges double m_dual_cost; double m_utilization; double m_capacity; double m_res_cap; //residual capacity double m_transittime; // transit time on edge with current speed double m_rot; // current rotation }; //Graph typedef adjacency_list< vecS , vecS , bidirectionalS, Port, Edge> mcf_graph; //descriptor typedefs typedef boost::graph_traits<mcf_graph>::vertex_descriptor vertex_descriptor; typedef boost::graph_traits<mcf_graph>::edge_descriptor edge_descriptor; //iterator typedefs typedef boost::graph_traits<mcf_graph>::vertex_iterator Viterator; typedef boost::graph_traits<mcf_graph>::edge_iterator Eiterator; typedef boost::graph_traits<mcf_graph>::in_edge_iterator IEiterator; typedef boost::graph_traits<mcf_graph>::out_edge_iterator OEiterator; template <typename edge_type_map> struct forfeited_edge_type { forfeited_edge_type() { } forfeited_edge_type( edge_type_map type) : forfeited(type) { } bool operator()(const edge_descriptor& e) const { return forfeited[e]==2; } edge_type_map forfeited; }; #endif And resource_extension and dominance functions here in res_path.h #ifndef RESPATH_H_ #define RESPATH_H_ #include <boost/config.hpp> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/r_c_shortest_paths.hpp> #include <iostream> #include "mcf_graph.h" #include "data.h" #include <boost/graph/graphviz.hpp> namespace std { class respath { public: respath(mcf_graph & m, Eiterator & comm); virtual ~respath(); private: mcf_graph & m_res_graph; Eiterator & commodities; }; // data structures for shortest path problem with transit time constraints (spptt) // ResourceContainer model struct spp_spptt_res_cont { spp_spptt_res_cont( double c = 0, double t = 0 ) : cost( c ), time( t ) {} spp_spptt_res_cont& operator=( const spp_spptt_res_cont& other ) { if( this == &other ) return *this; this->~spp_spptt_res_cont(); new( this ) spp_spptt_res_cont( other ); return *this; } double cost; double time; }; bool operator==( const spp_spptt_res_cont& res_cont_1,const spp_spptt_res_cont& res_cont_2 ){ return ( res_cont_1.cost == res_cont_2.cost && res_cont_1.time == res_cont_2.time ); } bool operator<( const spp_spptt_res_cont& res_cont_1,const spp_spptt_res_cont& res_cont_2 ) { if( res_cont_1.cost > res_cont_2.cost ) return false; if( res_cont_1.cost == res_cont_2.cost ) return res_cont_1.time < res_cont_2.time; return true; } // ResourceExtensionFunction model class ref_spptt { static double maxtt; public: static void setmaxtt(double tt){ maxtt=tt; } inline bool operator()( const mcf_graph& g, spp_spptt_res_cont& new_cont, const spp_spptt_res_cont& old_cont, boost::graph_traits <mcf_graph>::edge_descriptor ed) const { const Edge& arc_prop = get( edge_bundle, g )[ed]; new_cont.cost = old_cont.cost + arc_prop.m_cost; new_cont.time=old_cont.time + arc_prop.m_transittime; double& i_time = new_cont.time; return i_time <= (maxtt) ? true : false; } }; double ref_spptt::maxtt=0; // Dominance Function class dom_spptt { public: inline bool operator()( const spp_spptt_res_cont& res_cont_1, const spp_spptt_res_cont& res_cont_2 ) const { return res_cont_1.cost <= res_cont_2.cost && res_cont_1.time <= res_cont_2.time; } }; } /* namespace std */ #endif /* RESPATH_H_ */ -- Best Regards, Ph.D. Berit Dangaard Brouer Post Doc. DTU Management Engineering, Management Science Technical University of Denmark Department of Management Engineering Produktionstorvet, Bygning 426 2800 Kgs. Lyngby blof(a)dtu.dk <mailto:blof@man.dtu.dk> www.ms.man.dtu.dk <http://www.ms.man.dtu.dk> http://www.maersk.com/innovation/leadingthroughinnovation/enerplan/ Please read about the ENERPLAN project here <http://www.maersk.com/innovation/leadingthroughinnovation/enerplan/>

1 0

multi_index in managed_shared_memory
by Sebastien Nobert 11 Dec '13

11 Dec '13

Hi All, I'm trying to build a multi_index in managed shared memory with two (or more) hashed index but I get an "is an amiguous base of" error. I've already done that with one hash_uniq and a sequenced index and everything work fine. With two hashed index i get. boost/interprocess/detail/mpl.hpp:74:55: error: > ‘boost::multi_index::detail::hashed_index_node_impl<boost::interprocess::allocator<char, > boost::interprocess::segment_manager<char, > boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family>, > boost::interprocess::iset_index> > >’ is an ambiguous base of > ‘boost::multi_index::detail::hashed_index_node<boost::multi_index::detail::hashed_index_node<boost::multi_index::detail::index_node_base<element, > boost::interprocess::allocator<element, > boost::interprocess::segment_manager<char, > boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family>, > boost::interprocess::iset_index> > > > >’ > static const bool value = sizeof(dispatch(trigger())) == > sizeof(true_t); > With a hashed and an ordered index i get. boost/multi_index_container.hpp:161:52: error: no type named > ‘final_allocator_type’ in ‘boost::multi_index::multi_index_container< ... > and it ask me to attach the preprocessed file to my bug report. This is compiled on linux with gcc version 4.8.2 20131017 (Red Hat 4.8.2-1) (GCC) Should I open a bug report ? Am I doing something wrong ? Thanks a lot. Seb

3 4

[Log] Attribute formatting tricks ineffective -- my enums are printed as numbers.
by Andres Jaan Tack 11 Dec '13

11 Dec '13

I'm having some trouble with attribute formatting in boost::log that I haven't managed to figure out on my own. The case seems basic: I want to format my own severity enum as a string, for which I've produced the following (failing) example. Tested on clang-3.3 and clang-3.4 with boost-1.54 from macports, the minimal failing test produces the following output: $ clang++ --std=c++11 -c -DBOOST_ALL_DYN_LINK -I/opt/local/include/boost fail.cxx $ g++ -o fail -L/opt/local/lib -lboost_log-mt -lboost_log_setup-mt -lboost_system-mt -lboost_thread-mt fail.o $ ./fail 1: Booo! I would have expected "INFO: Booo!" according to my code. I've attached the complete fail.cxx here, in which I do all of: 1) Employ BOOST_LOG_ATTRIBUTE_KEYWORD, 2) Overload operator<< (std::ostream&, const my::severity&), 3) Overload operator<< (logging::formatting_ostream&, const logging::to_log_manip<...>&), and 4) Invoke register_simple_formatter_factory I can't find any guidance in the documentation or elsewhere on the internet that has managed to solve this -- Am I missing something obvious, or have I found a failing test case? -- Andres

1 0

Introduction
by Mihir Thakkar 10 Dec '13

10 Dec '13

Hello! I am new to open source, I know c++ and i am learning neural networks. I would like to contribute to boost c++ libraries. Please help me to get started. :)

2 1

Problem with linking files using boost::log with CMake Buildfile
by David Georg Reichelt 10 Dec '13

10 Dec '13

Hi, I've got problems compiling a program using boost with CMake (using Windows and MinGW 4.7.2, with -G "MinGW Makefiles"). Boost is compiled normaly with b2.exe --toolset=gcc --prefix=C:\cppLib\boost_1_55_0 and the folder seems to contain the right files. The original CMake-File compiled fine using Ubuntu. I've got a code using only boost::log and a CMake File containing the following boost-related-code: ADD_DEFINITIONS("-std=c++0x") SET(BOOST_ROOT "C:/cppLib/boost_1_55_0/") link_libraries (${Boost_LIBRARIES}) find_package( Boost 1.54.0 COMPONENTS log) if(Boost_FOUND) MESSAGE("Boost found") include_directories(${Boost_INCLUDE_DIRS}) add_executable(Hasselbrack ${AUTO_SOURCES}) endif() This code works right, but when I call make, I get the following errors: In file included from C:/cppLib/boost_1_55_0/boost/log/expressions/formatters/c_decorator.hpp:21:0, from C:/cppLib/boost_1_55_0/boost/log/expressions/formatters.hpp:29, from C:/cppLib/boost_1_55_0/boost/log/expressions.hpp:26, from C:\Users\DaGeRe\cpp\Minimalprojekt\main.cpp:3: C:/cppLib/boost_1_55_0/boost/log/detail/snprintf.hpp:45:9: Fehler: ╗::swprintf½ wurde nicht deklariert C:/cppLib/boost_1_55_0/boost/log/detail/snprintf.hpp:46:9: Fehler: ╗::vswprintf½ wurde nicht deklariert In file included from C:/cppLib/boost_1_55_0/boost/log/expressions/formatters.hpp:29:0, from C:/cppLib/boost_1_55_0/boost/log/expressions.hpp:26, from C:\Users\DaGeRe\cpp\Minimalprojekt\main.cpp:3: C:/cppLib/boost_1_55_0/boost/log/expressions/formatters/c_decorator.hpp: In statischer Elementfunktion ╗static std::size_t boost::log::v2s_mt_nt5::exp ressions::aux::c_decorator_traits<wchar_t>::print_escaped(wchar_t (&)[N], wchar_t)½: C:/cppLib/boost_1_55_0/boost/log/expressions/formatters/c_decorator.hpp:110:43: Fehler: ╗swprintf½ ist kein Element von ╗boost::log::v2s_mt_nt5::aux½ I tried to figure it out, the lines in snprintf are the following: using ::snprintf; using ::vsnprintf; but I can't find an error in this. The Include in the beginning of the file: #ifdef BOOST_LOG_USE_WCHAR_T #include <wchar.h> #endif // BOOST_LOG_USE_WCHAR_T seems to be exectued right (according to http://pubs.opengroup.org/onlinepubs/7990989775/xsh/wchar.h.html, snprintf is declared here). If I don't use ADD_DEFINITIONS("-std=c++0x"), I got the following errors: CMakeFiles\Hasselbrack.dir/objects.a(main.cpp.obj):main.cpp:(.text+0x12c): undefined reference to `boost::log::v2s_mt_nt5::core::get()' CMakeFiles\Hasselbrack.dir/objects.a(main.cpp.obj):main.cpp:(.text+0x143): undefined reference to `boost::log::v2s_mt_nt5::core::set_filter(boost::log ::v2s_mt_nt5::filter const&)' CMakeFiles\Hasselbrack.dir/objects.a(main.cpp.obj):main.cpp:(.text+0x1c7): undefined reference to `boost::log::v2s_mt_nt5::trivial::logger::get()' CMakeFiles\Hasselbrack.dir/objects.a(main.cpp.obj):main.cpp:(.text+0x20b): undefined reference to `boost::log::v2s_mt_nt5::trivial::logger::get()' CMakeFiles\Hasselbrack.dir/objects.a(main.cpp.obj):main.cpp:(.text+0x2e7): undefined reference to `std::ios_base::Init::~Init()' CMakeFiles\Hasselbrack.dir/objects.a(main.cpp.obj):main.cpp:(.text+0x308): undefined reference to `std::ios_base::Init::Init()' c:/mingw/bin/../lib/gcc/mingw32/4.7.2/../../../../mingw32/bin/ld.exe: CMakeFiles\Hasselbrack.dir/objects.a(main.cpp.obj): bad reloc address 0x1b in se ction `.text$_ZN5boost6detail15sp_counted_base7releaseEv[__ZN5boost6detail15sp_counted_base7releaseEv]' c:/mingw/bin/../lib/gcc/mingw32/4.7.2/../../../../mingw32/bin/ld.exe: final link failed: Invalid operation But nevertheless, boost is found and I can't figure out CMake seems to be unable to link it. The output of $(Boost_LIBRARIES) from CMake also seems correct: C:/cppLib/boost_1_55_0/stage/lib/libboost_log-mgw47-mt-1_55.dll . So I got no clue anymore what I could try. Has anybody an hint how to solve this? Best Regards, DaGeRe

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Is the following use of boost::function<> safe?
by David Goodenough 10 Dec '13

10 Dec '13

Let me preface this with the note that the whole idea behind what I'm trying to do is invoke an arbitrary function in a new thread, optionally delaying the invocation by some number of milliseconds That said, ----- threadrun.h ----- #ifndef _THREADRUN_H_ #define _THREADRUN_H_ #include <boost/function.hpp> namespace Thread { void ThreadRun(boost::function<void()> const &job); void ThreadDelayedRun(boost::function<void()> const &job, unsigned int delay); }; #endif ----- threadrun.h ----- ----- threadrun.cpp ----- #include "threadrun.h" static void DelayedRun(boost::function<void()> job, unsigned int delay) { Sleepms(delay); // Routine available elsewhere that simply sleeps for delay ms job(); } namespace Thread { void ThreadRun(boost::function<void()> const &job) { boost::thread thr = boost::thread(job); thr.detach(); // Not really necessary, but it does make it explicit that we'll never wait for the thread to finish } void ThreadDelayedRun(boost::function<void()> const &job, unsigned int delay) { boost::thread thr = boost::thread(boost::bind(DelayedRun, job, delay)); thr.detach(); // Not really necessary, but it does make it explicit that we'll never wait for the thread to finish } }; ----- threadrun.cpp ----- Use cases would be: void myFunc(int a, int b) { ... } int myFunc1(int a, int b) { ... return x } Thread::ThreadRun(boost::bind(myFunc, 1000, 17)); Thread::ThreadDelayedRun(boost::bind(myFunc1, 2000, 42), 5000); This appears to work correctly, I'm currently using boost 1.54 - haven't build 1.55 yet, but will do so in the near future. My only concern is the second case where I have myFunc1() whose return type is int, yet in the prototype for ThreadDelayedRun() I'm making it look a whole lot like it's void. The return type ultimately doesn't matter since this is specifically designed to be a "fire and forget" system, which means that any return value will be lost, there's no way for the invoking thread to recover it. So, is there anything dangerous about what I'm doing?

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Boost logo
by Oodini 10 Dec '13

10 Dec '13

Hello, I plan to do training about Boost, and so wanted to use the Boost logo on my slides. 1. Am I authorized to use the Boost logo ? 2. If so, where can I find it in a size larger from what I can see/find on the Boost site (ideally in a vectorial format) ? Thanks.

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mixing c++98 with c++11
by Chris Stankevitz 09 Dec '13

09 Dec '13

Hello, Please consider the following: application A depends on boost compiled libraries application A depends on library B library B depends on boost compiled libraries Q1: Will I have a problem if: application A is compiled with gcc c++11 library B is compiled with gcc c++98 boost compiled with gcc c++98 Q2: Will I have a problem if: application A is compiled with gcc c++11 library B is compiled with gcc c++11 boost compiled with gcc c++98 My concern is that boost produces different code in its headers based on whether or not the compiler supports c++11. Thank you, Chris

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Re: [Boost-users] [boost] [variant] Warning: variadic templates in boost::variant
by Igor R 09 Dec '13

09 Dec '13

> Development version of Boost.Variant library now uses C++11 variadic > templates when possible. > This leads to more compact binaries, more readable compiler error messages > and faster compilation times. Will it support MSVC12 (i.e. VS2013)? In particular, won't it be affected by the following bug: http://tinyurl.com/o2psdj5 ?

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[boost] [variant] Warning: variadic templates in boost::variant
by Antony Polukhin 09 Dec '13

09 Dec '13

Development version of Boost.Variant library now uses C++11 variadic templates when possible. This leads to more compact binaries, more readable compiler error messages and faster compilation times. However this: * breaks ABI (now variant is declared as `template <typename T0, typename... TN> class variant`) * breaks user code that was explicitly using BOOST_VARIANT_LIMIT_TYPES Code that was using BOOST_VARIANT_ENUM_PARAMS and BOOST_VARIANT_ENUM_SHIFTED_PARAMS macro *must* work correctly without any modifications. To disable variadic templates usage in variant define BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES. When all the tests will pass successfully changes will be merged to master branch, so there is a high chance that variadic templates will be supported by Boost 1.56. In case of appearance of hard to fix variadic templates errors in Boost libraries dependent on Boost.Variant - report them in this letter and I'll help in resolving issues. -- Best regards, Antony Polukhin

1 0

C++Now 2014: Call for Submissions, Updated deadlines
by Hartmut Kaiser 09 Dec '13

09 Dec '13

Updated submission dates! Please see below! ============================================== C++ Now Conference 2014 Aspen CO, USA, May 12-17, 2014, www.cppnow.org ============================================== For the full announcement online, please see here: http://cppnow.org/2013/10/21/2014-call-for-submissions/ Call for Submissions -------------------- We invite you to submit session proposals to the 3rd annual C++Now Conference (Aspen CO, USA, May 12-17, 2014). Building upon the resounding success of C++Now 2013 and five years of BoostCon, C++Now 2014 will present leading speakers from the whole C++ community. The C++Now Conference is dedicated to discussion and education about C++, an open and free language and standard. Our Conference will focus on discussion and education about open source software usage and developments in the C++ developer and user community. To reflect the breadth of the C++ and Boost communities, the conference includes sessions aimed at three constituencies: C++ and Boost end-users, hard-core Boost library and tool developers, and researchers pushing the boundaries of computation. The program fosters interaction and engagement within and across those groups, with an emphasis on hands-on, participatory sessions. As a multi-paradigm language, C++ is a melting pot where the most compelling ideas from other programming communities are blended in powerful ways. Historically, some of the most popular sessions at C++Now have highlighted these concepts, from DSLs to functional programming to transactional memory and more. Bring your C#, Python, Ruby or Haskell influences to bear in an environment that will broaden their exposure. At C++Now 2014 we would like to focus on the now established C++11 standard and the new, upcoming C++14 and how those standards are and will shape C++'s future. However, by no means is this intended to restrict the topics of proposals we hope to see. Any other topic related to C++ as outlined below is perfectly fine for submission. Important dates --------------- New proposal submissions due: December 22th, 2013. Proposals decisions sent (tentative program available): February 15th, 2014. Fully scheduled program available: February 28th, 2014. Best Presentation Awards ------------------------ We know how much effort it takes to prepare talks for our conference. For this reason we will award the best The awards will be given based on the audience's voting. Each award will include the author's name listed on the cover of the C++Now website for that year and a plaque containing all the C++Now conference information. Session topics -------------- Topics of interest include, but are not restricted to, the following: * C++11/14 and how it changes life for users and library writers * General tutorial sessions on C++11/14, the C++11/14 Standards library, and one or more Boost libraries * Parallelism in the new C++11/14 standard * Parallel, distributed and GPGPU topics relating to C++ * In-depth sessions on using specific Boost libraries * Case studies on using Boost * Experts panels * Advanced sessions on implementation techniques used within Boost libraries * Development workshops to extend or enhance existing Boost libraries * Workshops on design process * Infrastructure workshops such as Build tools, Website, Testing * Concepts and Generic Programming * Hardware and infrastructure presentations focused on how libraries can make better use of the technology * Software development tools and their application to C++ and or Boost * Other topics likely to be of great interest to C++ users and developers Interactive and collaborative sessions are encouraged, as this is the style of learning and participation that has proven most successful at such events. Sessions can be tutorial based, with an emphasis on interaction and participant involvement, or workshop based, whether hands-on programming or paper-based, discussion-driven collaborative work. Session formats --------------- Presentations Presentations focus on a practitioner's ideas and experience with anything relevant to C++11 or C++14, Boost and users. Panels Panels feature three or four people presenting their ideas and experiences relating to C++11 or C++14 and Boost's relevant, controversial, emerging, or unresolved issues. Panels may be conducted in several ways, such as comparative, analytic, or historic. Tutorials Tutorials are sessions at which instructors teach conference participants specific skills relevant to C++11 or C++14 and Boost. Workshops Workshops provide an active arena for advancements in Boost-relevant topics. Workshops provide the opportunity for experienced practitioners to develop new ideas about a topic of common interest and experience. Author's Corner Presentations These were introduced at BoostCon 2008, and were a great success. They are short (30 minute) sessions, focusing on tips on usage and design. In addition, we're looking to uncover the hidden design gems in Boost libraries. Tool Vendors Presentations We actively encourage tool vendors and ISP's to submit proposals for a special Tool Vendors Session Track aimed at products related to Boost and C++ (compilers, libraries, tools, etc.). Other formats may also be of interest. Don't hold back a proposal just because it doesn't fit into a pigeonhole. Submitting a proposal --------------------- Standard sessions are 90 minutes. You may submit a proposal for fractions or multiples of 90-minutes. Fractional proposals will be grouped into 90 minute sessions covering related topics. Longer sessions, such as tutorials and classes, will be assigned three hour (i.e. half day), or six hour (i.e. full day) time slots. Please include: * The working title. * Type of session: presentation, panel, tutorial, workshop, authors corner, vendor track, other. * A paragraph or two describing the topic covered, suitable for the conference web site. * Proposed length: 10-20 minute short talks, 45 minutes, 90 minutes, half day, full day. * Alternate lengths, if you are willing to make adjustments: 10-20 minute short-talks, 45 minutes, 90 minutes, half-day, full day. * Audience: users, developers, both. * Level: basic, intermediate, advanced. * A biography, suitable for the conference web site. * A photo of about 150 x 150 * Your public contact information (twitter handle, blog, website, google plus, etc.) * Your contact information (will not be made public). Submission details ------------------ All submissions should be made through the EasyChair conference management system: http://www.easychair.org/conferences/?conf=cppnow2014. If you have not already registered at EasyChair, you will need to do so in order to submit your proposal. All submissions will go through a peer review process. Authors are invited (but are not required) to submit PDF versions of full papers of up to 10 pages in ACM conference proceedings format (see http://www.acm.org/sigs/publications/proceedings-templates) The full papers are not required unless you want them published in the proceedings. All accepted proposals will be made available in the Association for Computing Machinery (ACM) Digital Library (approval pending). Best papers, after further reviews, will be considered to be book chapters or journal articles in a renowned journal. The session materials go on the C++ Now website and will be available to attendees. For general information on the C++ Now 2014 paper submission or the scope of technical papers solicited; please refer to the conference website at www.cppnow.org. For any other questions about the submission process or paper format, please contact the Program Committee at cppnow2014(a)easychair.com. If you have any technical problems with EasyChair, please contact EasyChair for help. Note: Presenters must agree to grant a non-exclusive perpetual license to publish submitted materials, either electronically or in print, in any media related to C++ Now. Hartmut Kaiser, email: hartmut.kaiser(a)gmail.com (Program Committee Chair) Joel Falcou, email: joel.falcou(a)lri.fr (Program Committee Co-Chair) Jon Kalb, , email: jon(a)kalbweb.com (Conference Chair) Dave Abrahams, dave(a)boostpro.com (Conference Chair) On behalf of the conference organizers

1 0

Thread synchronization
by Gonzalo Garramuno 08 Dec '13

08 Dec '13

I have an application (a video player), that uses three threads to play videos (one thread handles decoding, another video display, and another audio). These threads have a thread barrier to wait until all 3 threads finish. This works fine. Now, my video player supports playing back two movies at the same time (to have one as a background and one as a foreground). Currently this is done with the same code for both. My problem is that there's no sync between the two movies and I am puzzled on how to achieve synchronism. I am unsure whether a thread barrier can be waited twice by two threads or whether I should have a single barrier that waits on the 6 threads ( 2 decode, 2 video, 2 audio ). If someone has any insight, it would be appreciated.

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boost::iostreams::copy - sink - ENOSPC (No space left on device) error handling
by Dino Korah 07 Dec '13

07 Dec '13

Platform: GCC on Linux; boost 1.55. In the code fragment below, is there a way to handle ENOSPC? #include <fstream> #include <iostream> #include <boost/iostreams/filtering_streambuf.hpp> #include <boost/iostreams/copy.hpp> #include <boost/iostreams/filter/bzip2.hpp> // open input file stream of the bzip2 file std::ifstream ifs("file.bz2"); // open output stream to the "full" device // full device is a "utility-device" to check how applications handle ENOSPC // more details in "man full" std::ofstream ofs("/dev/full"); // Setup the iostreams filter boost::iostreams::filtering_streambuf<boost::iostreams::output> filters; filters.push(boost::iostreams::bzip2_decompressor()); filters.push(ofs); // "run" the filter boost::iostreams::copy(ifs, filters); If I do strace of the compiled binary, the code seem to infinitely call writev() with the same data and returns ENOSPC error. writev(4, [{NULL, 0}, {"DATA DATA "..., 4096}], 2) = -1 ENOSPC (No space left on device) How can this error be handled or made thrown as an error from boost::iostreams::copy() Is it possible to set appropriate exceptions() on the ofstream object? I tried ofs.exceptions(std::ios::badbit | std::ios::failbit) but it didn't make any difference.

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