September 2008 - Boost-users

[statechart] handling unexpected events
by Robert Mecklenburg 05 Oct '08

05 Oct '08

I'm attempting to use StateChart to model a simple socket protocol and I'm having difficulty understanding how to handle protocol errors. I've read the sections on Error handling and two phase exit without gaining much insight. Those sections seem to be concerned with user-written code that cannot complete and thus must throw an exception. The type of error I'm currently concerned with is an unexpected event. For example, in this simple protocol we must first receive a hello before being ready to handle requests. A request returns data and must be followed by a commit, which completes the transaction and returns us to the ready state. (start state) (hello event) -> (ready state) (ready state) (get event) -> (data delivered) (data delivered) (commit event) -> (ready state) My problem is this: how do I detect and recover when I'm in the (data delivered) state and the next event is not a (commit event)? The only thing I can see is that the unconsumed_event() function is called with the unexpected event object. What I'd like to do in this function is: 1. Abort my transaction and force the state machine back to the Ready state. I'm not sure how to do this. 2. Reprocess the unexpected event if it is a hello or get, discard it otherwise. I'm not sure how to do this, either. At a more abstract level, it seems that unconsumed_event() is the only way to deal with an unexpected event and to try to reset the state machine. Is this true? Thanks, -- Robert

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[Boost-user] bjam and env var
by Jérémie Fouché 03 Oct '08

03 Oct '08

Hi everybody I'm creating python modules with boost, and I'm using bjam to compile them (because, as written in the doc, it is the easiest way to compile python module created with boost.python). Actually, my jam script is specific to my directory structure. If I want to change my directory structure, or shared my project with someone who haven't the same directory structure (which is always the case), my jam files need to be changed. My jam files are at the end of this post. I tried to use environment variables without success. If I create a BOOST_ROOT env var, I can't use it in my JamRoot file, because $(BOOST_DIR) is always empty. I also tried to create a var in my user-config.jam, but the var isn't visible in my JamRoot file. So, here are my questions : 1 - Is there a good way to do this ? 2 - I didn't find exactly what is boost-build.jam for, have you an explanation ? Thanks boost-build.jam : boost-build /_Perso/projets/lib/boost_1_36_0/tools/build/v2 ; JamRoot : wx = /_Perso/projets/lib/wxWidgets2.8 ; # Specify the path to the Boost project. If you move this project, # adjust this path to refer to the Boost root directory. use-project boost : ../../../../lib/boost_1_36_0 ; # Set up the project-wide requirements that everything uses the # boost_python library from the project whose global ID is /boost/python. project : requirements <library>/boost/python//boost_python ; # Declare the extension module. python-extension gui : gui.cpp : <include>$(wx)/include <include>$(wx)/lib/gcc_dll/mswu <define>__GNUWIN32__ <define>__WXMSW__ <define>WXUSINGDLL <define>wxUSE_UNICODE <library-file>$(wx)/lib/gcc_dll/libwxmsw28u.a ; -- Jérémie

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[MPL][FUSION] generate fusion::map from mpl::vector
by Manuel Jung 01 Oct '08

01 Oct '08

Hi, I get as template parameter a mpl::vector with various types. Now want to generate one object of each type. To do so, i like to generate a fusion::map, which has as key the type itself (from the mpl::vector) and as object e.g. boost::promise_stream< type >. Well this is what i've got so far: template< typename OutSignatures > class filter_impl{ typedef typename mpl::transform< OutSignatures, boost::promise_stream<mpl::_1> >::type OutStreams; typedef typename mpl::transform< OutSignatures, OutStreams, fusion::make_pair< mpl::_1, mpl::_2 > >::type OutPairs; typedef typename fusion::result_of::as_map< fusion::vector< OutPairs > >::type Out_type; } This compiles fine. But i'm not able to generate some fusion::map from the Out_type. I get compiling errors than. Well I'm new to the whole MPL and fusion stuff. Am i doing the right things? Or maybe my goal could be achived easier? Thanks for any hints, Kind Regards Manuel

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[program_options] linker error LNK2005 (symbol already defined in object)
by Olaf Peter 01 Oct '08

01 Oct '08

Hi, I've got the linker error LNK2005 (http://msdn.microsoft.com/en-us/library/72zdcz6f(VS.80).aspx) using MSVC80 (Studio 2005): libboost_program_options-vc80-mt-1_35.lib(value_semantic.obj) : error LNK2005: "public: __thiscall boost::program_options::invalid_option_value::invalid_option_value(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (??0invalid_option_value@program_options@boost@@QAE@ABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z) ist bereits in boost_program_options-vc80-mt-1_35.lib(boost_program_options-vc80-mt-1_35.dll) definiert. libboost_program_options-vc80-mt-1_35.lib(value_semantic.obj) : error LNK2005: "public: virtual char const * __thiscall boost::program_options::validation_error::what(void)const " (?what@validation_error@program_options@boost@@UBEPBDXZ) ist bereits in boost_program_options-vc80-mt-1_35.lib(boost_program_options-vc80-mt-1_35.dll) definiert. libboost_program_options-vc80-mt-1_35.lib(value_semantic.obj) : error LNK2005: "void __cdecl boost::program_options::validate(class boost::any &,class std::vector<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,class std::allocator<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > > > const &,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > *,int)" (?validate@program_options@boost@@YAXAAVany@2@ABV?$vector@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V?$allocator@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@2@@std@@PAV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@5@H@Z) ist bereits in boost_program_options-vc80-mt-1_35.lib(boost_program_options-vc80-mt-1_35.dll) definiert. libboost_program_options-vc80-mt-1_35.lib(value_semantic.obj) : error LNK2005: "private: virtual void __thiscall boost::program_options::value_semantic_codecvt_helper<char>::parse(class boost::any &,class std::vector<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,class std::allocator<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > > > const &,bool)const " (?parse@?$value_semantic_codecvt_helper@D@program_options@boost@@EBEXAAVany@3@ABV?$vector@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V?$allocator@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@2@@std@@_N@Z) ist bereits in boost_program_options-vc80-mt-1_35.lib(boost_program_options-vc80-mt-1_35.dll) definiert. libboost_program_options-vc80-mt-1_35.lib(options_description.obj) : error LNK2005: "public: class boost::program_options::options_description_easy_init __thiscall boost::program_options::options_description::add_options(void)" (?add_options@options_description@program_options@boost@@QAE?AVoptions_description_easy_init@23@XZ) ist bereits in boost_program_options-vc80-mt-1_35.lib(boost_program_options-vc80-mt-1_35.dll) definiert. libboost_program_options-vc80-mt-1_35.lib(options_description.obj) : error LNK2005: "class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl boost::program_options::operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,class boost::program_options::options_description const &)" (??6program_options@boost@@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@std@@AAV23@ABVoptions_description@01@@Z) ist bereits in boost_program_options-vc80-mt-1_35.lib(boost_program_options-vc80-mt-1_35.dll) definiert. libboost_program_options-vc80-mt-1_35.lib(options_description.obj) : error LNK2005: "public: __thiscall boost::program_options::options_description::options_description(unsigned int)" (??0options_description@program_options@boost@@QAE@I@Z) ist bereits in boost_program_options-vc80-mt-1_35.lib(boost_program_options-vc80-mt-1_35.dll) definiert. libboost_program_options-vc80-mt-1_35.lib(options_description.obj) : error LNK2005: "public: __thiscall boost::program_options::options_description::options_description(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &,unsigned int)" (??0options_description@program_options@boost@@QAE@ABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@I@Z) ist bereits in boost_program_options-vc80-mt-1_35.lib(boost_program_options-vc80-mt-1_35.dll) definiert. libboost_program_options-vc80-mt-1_35.lib(options_description.obj) : error LNK2005: "public: class boost::program_options::options_description_easy_init & __thiscall boost::program_options::options_description_easy_init::operator()(char const *,char const *)" (??Roptions_description_easy_init@program_options@boost@@QAEAAV012@PBD0@Z) ist bereits in boost_program_options-vc80-mt-1_35.lib(boost_program_options-vc80-mt-1_35.dll) definiert. libboost_program_options-vc80-mt-1_35.lib(options_description.obj) : error LNK2005: "public: class boost::program_options::options_description_easy_init & __thiscall boost::program_options::options_description_easy_init::operator()(char const *,class boost::program_options::value_semantic const *,char const *)" (??Roptions_description_easy_init@program_options@boost@@QAEAAV012@PBDPBVvalue_semantic@12@0@Z) ist bereits in boost_program_options-vc80-mt-1_35.lib(boost_program_options-vc80-mt-1_35.dll) definiert. libboost_program_options-vc80-mt-1_35.lib(options_description.obj) : error LNK2005: "public: class boost::program_options::options_description & __thiscall boost::program_options::options_description::add(class boost::program_options::options_description const &)" (?add@options_description@program_options@boost@@QAEAAV123@ABV123@@Z) ist bereits in boost_program_options-vc80-mt-1_35.lib(boost_program_options-vc80-mt-1_35.dll) definiert. libboost_program_options-vc80-mt-1_35.lib(convert.obj) : error LNK2005: "class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > __cdecl boost::program_options::to_internal(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (?to_internal@program_options@boost@@YA?AV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@ABV34@@Z) ist bereits in boost_program_options-vc80-mt-1_35.lib(boost_program_options-vc80-mt-1_35.dll) definiert. using the linker options: /O2 /Ob2 /I "C:\Cpp\boost_1_35_0" /I ... /D "WIN32" /D "_WINDOWS" /D "NDEBUG" /D "BOOST_ENABLE_ASSERT_HANDLER=1" /D "QT_DLL" /D "QT_GUI_LIB" /D "QT_CORE_LIB" /D "QT_NO_DEBUG" /D "CMAKE_INTDIR=\"Release\"" /D "_MBCS" /FD /EHsc /MD /Fo"eda.dir\Release\\" /Fd"D:/work/build/Release/eda.pdb" /W3 /nologo /c /TP /errorReport:prompt Any ideas what happened here? Thanks, Olaf

5 7

Simple telnet client demonstration with boost asio asynchronous I/O
by Jeff Gray 01 Oct '08

01 Oct '08

I've been teaching myself how to use the asynchronous I/O capabilities in Boost asio. I took the chat client example code that came with Boost and modified it to act as a more general telnet client. Hopefully, this may be of use to others trying to get to grips with the basics of this way of working. More experienced developers can feel free to suggest better ways of doing things here. This is just a demonstration - it does not do all the niceties of a full application, but hopefully covers the basics. I wrote this for a Linux system, but the only system specific thing is the code that enables single keypress input for cin.get(). I'm sure you can easily find alternatives for your system to achieve the same result. Enjoy, Jeff

3 5

Re: [Boost-users] [Statechart] Passing Arguments in the Events Concept
by Babi Seal 30 Sep '08

30 Sep '08

Thanks for your prompt response. Yes it works really well. ----- Original Message ---- From: Andreas Huber <ahd6974-spamboostorgtrap(a)yahoo.com> To: boost-users(a)lists.boost.org Sent: Tuesday, September 30, 2008 1:08:24 PM Subject: Re: [Boost-users] [Statechart] Passing Arguments in the Events Concept Hi > I have been researching the Boost archives, Tutorials, > examples and I do find references to the fact that it is > possible to provide arguments along with Events that a > custom_reaction (in self-transition) can selectively > "react" on based on the value of the argument but > I am unable to articulate it using the Boost Statechart > library. I just realized that there is not a single example on how to pass arguments with events. It's very easy to do, though: struct EvWhatever : sc::event< EvWhatever > { int Arg1; double Arg2; // More arguments here }; You might want to add a constructor that accepts corresponding arguments and sets the data members Arg1 & Arg2 accordingly. You can access Arg1 & Arg2 in the react member function, in a transition action or the function called by an in_state_reaction. Hope this helps. if not, please let me know. Regards, -- Andreas Huber

1 0

asio async_accept
by Etienne Philip Pretorius 30 Sep '08

30 Sep '08

Just a quick question about the async_accept() in acceptor. Must the accept_handler be declared as a static member function within my class? The online examples do not seem to do this at all, and if I try it without the static keyword on my private member function then the compiler complains about it not matching the signature. Etienne Pretorius

5 10

[Proto] Evaluating non-trivial expression
by Joel Falcou 30 Sep '08

30 Sep '08

Let's say I have grammar etc.. for writing algebra code like : a = b+c, u = x + y, z = 3*e; and have each sub expression containing a = call to be evaluated on a different processor. Where can I put the evaluation call using the context ? In the destructor of my associated expression ?

2 4

[Phoenix] review reminder
by Hartmut Kaiser 30 Sep '08

30 Sep '08

All, this is just a gentle reminder for all of you willing and planning to write a review for Joel de Guzman's and Dan Marsden's library Phoenix V2. The review ends tomorrow, September 30th. If you are for some reason not able to write the review before tomorrow night, please get in contact with me directly, so we can work something out. Regards Hartmut Review Manager

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Re: [Boost-users] [Statechart] Passing Arguments in the Events Concept
by Andreas Huber 30 Sep '08

30 Sep '08

Hi > I have been researching the Boost archives, Tutorials, > examples and I do find references to the fact that it is > possible to provide arguments along with Events that a > custom_reaction (in self-transition) can selectively > "react" on based on the value of the argument but > I am unable to articulate it using the Boost Statechart > library. I just realized that there is not a single example on how to pass arguments with events. It's very easy to do, though: struct EvWhatever : sc::event< EvWhatever > { int Arg1; double Arg2; // More arguments here }; You might want to add a constructor that accepts corresponding arguments and sets the data members Arg1 & Arg2 accordingly. You can access Arg1 & Arg2 in the react member function, in a transition action or the function called by an in_state_reaction. Hope this helps. if not, please let me know. Regards, -- Andreas Huber When replying by private email, please remove the words spam and trap from the address shown in the header.

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