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[proposal] are_same on type_traits
by skypjack 06 Aug '13

06 Aug '13

Hi all, I've developed, tested and documented a variadic extension of is_same (named are_same). It can be useful to verify more than two arguments using a single expression. I sent the proposal to the devel list. However I would like to know if it can be of interest for you. Thanks in advance for your reply. Best Regards, Michele --

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[Coroutine] Unresolved externals with VC2012
by Szymon Gatner 06 Aug '13

06 Aug '13

Hi, the following simplest test code does not compile with Visual C++ 2012: #include <boost/coroutine/all.hpp> typedef boost::coroutines::coroutine<int()> Coro; void coroFunc(Coro::caller_type& co) { } int main() { Coro c(coroFunc); } giving: 1>------ Build started: Project: coro_testbed, Configuration: Debug Win32 ------ 1>main.obj : error LNK2019: unresolved external symbol "public: static unsigned int __cdecl boost::coroutines::detail::standard_stack_allocator::default_stacksize(void)" (?default_stacksize@standard_stack_allocator@detail@coroutines@boost@@SAIXZ) referenced in function "public: __thiscall boost::coroutines::attributes::attributes(void)" (??0attributes@coroutines @boost@@QAE@XZ) 1>main.obj : error LNK2019: unresolved external symbol "public: void __thiscall boost::coroutines::detail::standard_stack_allocator::allocate(struct boost::coroutines::stack_context &,unsigned int)" (?allocate@standard_stack_allocator@detail@coroutines@boost@ @QAEXAAUstack_context@34@I@Z) referenced in function "public: __thiscall boost::coroutines::detail::stack_tuple<class boost::coroutines::detail::standard_stack_allocator>::stack_tuple<class boost::coroutines::detail::standard_stack_allocator>(class boost::coroutines::detail::standard_stack_allocator const &,unsigned int)" (??0?$stack_tuple@Vstandard_stack_allocator@detail@coroutines@boost@ @@detail@coroutines@boost@@QAE@ABVstandard_stack_allocator@123@I@Z) 1>main.obj : error LNK2019: unresolved external symbol "public: void __thiscall boost::coroutines::detail::standard_stack_allocator::deallocate(struct boost::coroutines::stack_context &)" (?deallocate@standard_stack_allocator @detail@coroutines@boost@@QAEXAAUstack_context@34@@Z) referenced in function "public: __thiscall boost::coroutines::detail::stack_tuple<class boost::coroutines::detail::standard_stack_allocator>::~stack_tuple<class boost::coroutines::detail::standard_stack_allocator>(void)" (??1?$stack_tuple@Vstandard_stack_allocator@detail@coroutines@boost@ @@detail@coroutines@boost@@QAE@XZ) 1>main.obj : error LNK2019: unresolved external symbol "public: __thiscall boost::coroutines::detail::coroutine_context::coroutine_context(void)" (??0coroutine_context@detail@coroutines@boost@@QAE@XZ) referenced in function "public: __thiscall boost::coroutines::detail::coroutine_base<int __cdecl(void)>::coroutine_base<int __cdecl(void)>(void (__cdecl*)(int),struct boost::coroutines::stack_context *,bool,bool)" (??0?$coroutine_base@$$A6AHXZ@detail@coroutines@boost@@QAE@P6AXH @ZPAUstack_context@23@_N2@Z) 1>main.obj : error LNK2019: unresolved external symbol "public: __thiscall boost::coroutines::detail::coroutine_context::coroutine_context(void (__cdecl*)(int),struct boost::coroutines::stack_context *)" (??0coroutine_context@detail@coroutines@boost@@QAE@P6AXH @ZPAUstack_context@23@@Z) referenced in function "public: __thiscall boost::coroutines::detail::coroutine_base<int __cdecl(void)>::coroutine_base<int __cdecl(void)>(void (__cdecl*)(int),struct boost::coroutines::stack_context *,bool,bool)" (??0?$coroutine_base@$$A6AHXZ@detail@coroutines@boost@@QAE@P6AXH @ZPAUstack_context@23@_N2@Z) 1>main.obj : error LNK2019: unresolved external symbol "public: __thiscall boost::coroutines::detail::coroutine_context::coroutine_context(class boost::coroutines::detail::coroutine_context const &)" (??0coroutine_context@detail@coroutines@boost@@QAE@ABV0123@@Z) referenced in function "public: __thiscall boost::coroutines::detail::coroutine_base<void __cdecl(int)>::coroutine_base<void __cdecl(int)>(class boost::coroutines::detail::coroutine_context const &,bool,bool)" (??0?$coroutine_base@$$A6AXH@Z@detail@coroutines@boost@ @QAE@ABVcoroutine_context@123@_N1@Z) 1>main.obj : error LNK2019: unresolved external symbol "public: class boost::coroutines::detail::coroutine_context & __thiscall boost::coroutines::detail::coroutine_context::operator=(class boost::coroutines::detail::coroutine_context const &)" (??4coroutine_context@detail@coroutines@boost@@QAEAAV0123@ABV0123@@Z) referenced in function "private: void __thiscall boost::coroutines::detail::coroutine_object<int __cdecl(void),void (__cdecl*)(class boost::coroutines::coroutine<void __cdecl(int),1> &),class boost::coroutines::detail::standard_stack_allocator,class std::allocator<class boost::coroutines::coroutine<int __cdecl(void),0> >,class boost::coroutines::coroutine<void __cdecl(int),1>,int,0>::enter_(void)" (?enter_@?$coroutine_object@ $$A6AHXZP6AXAAV?$coroutine@$$A6AXH@Z$00@coroutines@boost@ @@ZVstandard_stack_allocator@detail@23@V?$allocator@V?$coroutine@ $$A6AHXZ$0A@@coroutines@boost@@@std@@V123@H$0A@@detail@coroutines@boost@ @AAEXXZ) 1>main.obj : error LNK2019: unresolved external symbol "public: int __thiscall boost::coroutines::detail::coroutine_context::jump(class boost::coroutines::detail::coroutine_context &,int,bool)" (?jump@coroutine_context@detail@coroutines@boost@@QAEHAAV1234@H_N@Z) referenced in function "private: void __thiscall boost::coroutines::detail::coroutine_object<int __cdecl(void),void (__cdecl*)(class boost::coroutines::coroutine<void __cdecl(int),1> &),class boost::coroutines::detail::standard_stack_allocator,class std::allocator<class boost::coroutines::coroutine<int __cdecl(void),0> >,class boost::coroutines::coroutine<void __cdecl(int),1>,int,0>::enter_(void)" (?enter_@?$coroutine_object@ $$A6AHXZP6AXAAV?$coroutine@$$A6AXH@Z$00@coroutines@boost@ @@ZVstandard_stack_allocator@detail@23@V?$allocator@V?$coroutine@ $$A6AHXZ$0A@@coroutines@boost@@@std@@V123@H$0A@@detail@coroutines@boost@ @AAEXXZ) 1>c:\users\bravo\documents\visual studio 2012\Projects\coro_testbed\Debug\coro_testbed.exe : fatal error LNK1120: 8 unresolved externals ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ========== Regards, Szymon -- Szymon Gatner The Lordz Games Studio www.thelordzgamesstudio.com

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Re: [Boost-users] Derived class is not serialising/de-serialising...
by Marcus MacWilliam 06 Aug '13

06 Aug '13

Hello, My previous post contained a minimal example, which was incomplete, deliberately so as not to bloat the post with code. However Jeff Flynn has requested a minimal code example. I have attached several files for classes to this e-mail. * BaseClass - the base class, which has a serialize method * DerivedClass - a sub-class with its own serialize method * InstantiableClass - the class actually instantiated from DerivedClass * Main - code example of the client/server that serializes and de-serializes the InstantiableClass object. Our system automatically inserts some pre-compiled headers so to get the code to compile you may need to add your own #includes. The output from the main program is this: Serializing... BOOST: I am an Instantiable class object BOOST: I am in BaseClass::serialize De-serializing... BOOST: I am an Instantiable class object BOOST: I am in BaseClass::serialize Assertion failed: dynamic_cast<InstantiableClass&>(object).getCom() == 20, file Main.cc, line 8 This highlights the polymorphism problem in a nutshell. The overloaded what() method is telling me that in both the client and server code the objects is an InstantiableClass object. However the Derived::serialize is not being called on either side. Thus the data (m_com) from the DerivedClass is not being serialized and is lost. The compiler, and debugger, is telling me my object is an InstantiableClass, however when boost calls serialize on the object, the code in the BaseClass and not the Derived class is being called. Any help greatly appreciated. -- Marcus A.T MacWilliam, Senior Software Engineer. 1Spatial Ltd. Tel: +44 (0)1223 420414, ext 2289, Mob: +44 (0)7803 706597. E-Mail: marcus.macwilliam(a)1spatial.com Skype:marcus.macwilliam Tennyson House, 7 Cambridge Business Park, Cambridge, CB4 0WZ. Registered in England No. 4785688, VAT Reg. No. 135539408. Website: http://www.1spatial.com/ E-mail: info(a)1spatial.com

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Removing all support for Visual C++ 7.0, GCC 3.2 and other old compilers
by Daniel James 06 Aug '13

06 Aug '13

Hello all, There has been some discussion on the development list about dropping all support for old C++ compilers. This will allow us to remove a lot of workarounds and simplify the code but before doing so it's a good idea to find out if anyone is still using them. Using boost with these compilers will cause a compile error in the config library (you can work round that using a custom configuration, but it's unlikely you'll be able to get much to work). The currently proposed versions for removing support are: Digital Mars 8.40 and earlier Visual C++ 7.0 and earlier GCC 3.2 and earlier Intel C++ 5.0 and earlier Which is, I think, a very cautious list. There's also a good chance that we might want to remove support for Borland C++ 5.x. Is there anyone still using those compilers? Just to be clear, this doesn't mean we'll be fully supporting all compilers later than these. Old compilers such as Visual C++ 7.1 and gcc 3.4 won't have a config error and we won't deliberately remove support, but support will be patchy. Many libraries (especially new ones) don't support those compilers, and we also don't have any formal testing for them, so if a new change breaks something, it might not be noticed. If you are still using compilers which are a little more recent than the ones listed above, it might still be worth mentioning in case we consider removing support for them in the future. Thanks in advance for any response, Daniel James

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Using boost_foreach with c++ enumerations
by Tim Burgess 06 Aug '13

06 Aug '13

Hi, Is it possible to use boost_foreach to iterate over the members of a c++ enum? If so, can anybody point me to an example? Many thanks in advance. Best wishes. Tim Burgess Raised Bar Ltd. T: 01827 719822 M: 07989 486976 W: http://www.raisedbar.net

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[Spirit/Qi] Malformed JSON parser
by Szymon Gatner 05 Aug '13

05 Aug '13

Hi, I am trying to add a support for degenerate / corner cases for my JSON parser. First I needed support for malformed null values for object members like that: obj : { "bad_member: , "correct_member: null } I would like the parser to generate same result for both members in that case (null value). I eventually came up with custom semantic action that does the job: struct MakeMember { typedef void result_type; template <class Arg1, class Ctx> result_type operator()(Arg1& arg1, Ctx& ctx, bool& b) const { using namespace boost::fusion; auto m0 = boost::fusion::at_c<0>(arg1); auto m1 = boost::fusion::at_c<1>(arg1); ctx.attributes.car.first = m0; ctx.attributes.car.second = m1 ? *m1 : NullT(); } }; but I have a feeling that is not the best way to do it. I would rally appreciate an advice on that. Secondly I want to add support for empty array members: obj : { "empty_array" : [] } but this time I am totally lost. My array parser looks like this: array = '[' >> value % ',' >> ']'; which is only god for 1 or more element list. I tried array = '[' >> -(value % ',') >> ']'; and altho it compiled it still didn't reckognize "[]' as Array object. Full source code of parser / grammar attched. Regards, Szymon

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Trying out Build on Windows, have questions
by Daryle Walker 05 Aug '13

05 Aug '13

After using a bunch of IDEs to compile my trial Boost code on Windows, I'm trying out Boost's included build system. I've been using the directions at http://www.boost.org/doc/libs/1_54_0/more/getting_started/index.html. I'm using a 32-bit Windows 8 Pro laptop. I have the MinGW-Builds version of GCC 4.8.1 installed. I downloaded a copy of Clang 3.3, built with the aforementioned GCC. I also have Visual Studio Express 2012 (v11.0) installed, the Desktop version along with the Metro and Web versions. The copy of Clang is installed into the same directories as GCC, and the "bin" sub-directory is in my PATH. I'm using a Subversion copy of the Boost libraries. Per the Getting Started instructions, I changed to the Boost Subversion directory and ran "bootstrap." I'm using a "user-config.jam" file of: //===== using gcc : 4.8 : : <cxxflags>-std=c++11 ; using msvc : 11.0 : "C:\Program Files\Microsoft Visual Studio 11.0\VC\bin\cl" ; using clang : 3.3 : : <cxxflags>-std=c++11 ; //===== Then I ran ".\b2", and the GCC version of the Boost libraries were built. Then I ran ".\b2 toolset=msvc" for the Visual Studio version. When I tried ".\b2 toolset=clang", it failed miserably since it couldn't find any of the standard headers. Now I've heard that Clang can build for Windows, but actually using it is broken (no matter how it's built). Is there a way to adjust the clang entry in my "user-config.jam" so it gets all the stuff it needs from the GCC installation? I got the sample regex program to build with GCC: //===== C:\Users\Daryle\Documents\Projects>g++ -I ..\Repositories\boost-trunk example2.c pp -o example2 -L ..\Repositories\boost-trunk\stage\lib -lboost_regex-mgw48-mt-1 _55 //===== but not with MSVC: //===== C:\Users\Daryle\Documents\Projects>cl /EHsc /I ..\Repositories\boost-trunk examp le2.cpp /link /LIBPATH:C:\Users\Daryle\Documents\Repositories\boost-trunk\stage \lib Microsoft (R) C/C++ Optimizing Compiler Version 17.00.51106.1 for x86 Copyright (C) Microsoft Corporation. All rights reserved. example2.cpp Microsoft (R) Incremental Linker Version 11.00.51106.1 Copyright (C) Microsoft Corporation. All rights reserved. /out:example2.exe /LIBPATH:C:\Users\Daryle\Documents\Repositories\boost-trunk\stage\lib example2.obj LINK : fatal error LNK1104: cannot open file 'libboost_regex-vc110-mt-s-1_55.lib ' //===== When I looked at the library-storage directory, there were no variants with "-s-". Should I run "b2," which is now in my PATH, again to add the required variants? What options do I need to add to the command line? Daryle W.

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boost logging to file
by Jarrett Chisholm 04 Aug '13

04 Aug '13

Thanks to everyone who's replied to my previous boost logging question - still having some issues I'm afraid :S I've been struggling with boost log for a while now - I got their simple example writing to a log file (http://boost-log.sourceforge.net/libs/log/example/doc/tutorial_file.cpp) However, when I try to copy that code into my own 'Logger' class, I can't get it to write to the log file. I can see the file `default.log` get created, but there is nothing in it. I'm on debian 7 64bit. Everything compiles fine - compile line is: g++ -o build/Logger.o -c -std=c++11 -Wall -g -O0 -DBOOST_LOG_DYN_LINK -DDEBUG src/Logger.cpp g++ -o build/logtest build/Logger.o -lboost_log -lboost_log_setup -lboost_date_time -lboost_thread -lboost_wave -lboost_regex -lboost_program_options Here's my code: `Logger.cpp` #include "Logger.h" namespace logging = boost::log; namespace sinks = boost::log::sinks; namespace src = boost::log::sources; namespace expr = boost::log::expressions; namespace attrs = boost::log::attributes; namespace keywords = boost::log::keywords; namespace dhlogging { Logger::Logger(std::string fileName) { initialize(fileName); } Logger::Logger(Logger const&) { } Logger::~Logger() { } Logger* Logger::logger_ = nullptr; Logger* Logger::getInstance(std::string logFile) { if ( Logger::logger_ == nullptr ) { logging::add_file_log( logFile ); logging::core::get()->set_filter ( logging::trivial::severity >= logging::trivial::info ); logging::add_common_attributes(); Logger::logger_ = new Logger(logFile); } return Logger::logger_; } void Logger::initialize(std::string fileName) { BOOST_LOG(log_) << "Hello, World!"; BOOST_LOG_SEV(log_, info) << "Hello, World2!"; } void Logger::logInfo(std::string message) { BOOST_LOG_SEV(log_, info) << message; } void Logger::logDebug(std::string message) { BOOST_LOG_SEV(log_, debug) << message; } void Logger::logWarn(std::string message) { BOOST_LOG_SEV(log_, warning) << message; } void Logger::logError(std::string message) { BOOST_LOG_SEV(log_, error) << message; } void Logger::logFatal(std::string message) { BOOST_LOG_SEV(log_, fatal) << message; } } int main(int, char*[]) { logging::add_common_attributes(); using namespace logging::trivial; dhlogging::Logger::getInstance()->logInfo("himom"); return 0; } `Logger.h` #ifndef LOGGER_H_ #define LOGGER_H_ #include <boost/log/core.hpp> #include <boost/log/trivial.hpp> #include <boost/log/expressions.hpp> #include <boost/log/sinks/text_file_backend.hpp> #include <boost/log/utility/setup/file.hpp> #include <boost/log/utility/setup/common_attributes.hpp> #include <boost/log/sources/severity_logger.hpp> #include <boost/log/sources/record_ostream.hpp> namespace logging = boost::log; namespace sinks = boost::log::sinks; namespace src = boost::log::sources; namespace expr = boost::log::expressions; namespace attrs = boost::log::attributes; namespace keywords = boost::log::keywords; using namespace logging::trivial; namespace dhlogging { class Logger { public: static Logger* getInstance(std::string logFile = "default.log"); void logInfo(std::string message); void logDebug(std::string message); void logWarn(std::string message); void logError(std::string message); void logFatal(std::string message); private: Logger(std::string fileName); Logger(Logger const&); Logger& operator=(Logger const&); virtual ~Logger(); void initialize(std::string fileName); src::severity_logger< severity_level > log_; static Logger* logger_; // singleton instance }; } #endif /* LOGGER_H_ */ Anyone have any ideas? Jarrett

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Boost Iterator: Limiting an existing iterator
by אנטולי קרס נר 03 Aug '13

03 Aug '13

Hello, I'm writing a C++ class which has an STL container as a data member, and I'd like to write an iterator class which allows to iterate through the container. Which container is used, is implementation detail. I want the iterator to be a ForwardIterator, even if a random-access container is used, e.g. std::vector. What's the quick and simple way to define an iterator adapter class which uses the "base" iterator's functions, but only the ones supported by a forward iterator? The reason I need it is error detection. If the user gets a random-access iterator and treats it as such, the compiler won't complain, but in future versions of my code the user's code may break because random access shouldn't really be supported, e.g. if I change from vector to list. Thanks in advance, fr33domlover Hmmm... I guess using boost::iterator_adapter should help

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[asio] using libgamin
by Alexander Nagel 03 Aug '13

03 Aug '13

Hello, one can use "signal_set" to connect to a SIGHUP signal and then reload a configuration file. I am thinking about a different approach. What about using libgamin to get notified if the config file changes and then reload automatically, if the config file is correct and valid. Is it possible to implement that behavior with asio? I read through the reference but I couldn't find something. I am not yet familiar with all aspects of asio. Perhaps I have overread it. Does anybody have a hint or an idea, please? regards, Alexander -- I would prefer to have encrypted communication. If you also prefer to encrypt emails, please do. Alexander Nagel Email: alexander(a)acwn.de Homepage: http://www.acwn.de/

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