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serialization std::map
by Adam Szeliga 17 Jul '09

17 Jul '09

Why I can not input from archive std::map ? line: inputArchive >> inputContainer causes compile error: Thanks Adam #include <string> #include <iostream> #include <fstream> #include <sstream> #include <map> #include <boost/serialization/map.hpp> #include <boost/serialization/serialization.hpp> #include <boost/serialization/string.hpp> #include <boost/serialization/level.hpp> #include <boost/serialization/tracking.hpp> #include <boost/serialization/split_free.hpp> #include <boost/serialization/base_object.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_wiarchive.hpp> #include <boost/archive/text_woarchive.hpp> class A { public: A() {}; A(std::string const & s): s(s) { } virtual ~A() {}; private: std::string s; friend std::ostream & operator<<(std::ostream & os, A const & a); friend class boost::serialization::access; template<class Archive> void serialize(Archive & archive, unsigned int const version) { archive & s; } }; std::ostream & operator<<(std::ostream & os, A const & a) { return os << a.s; } typedef std::map<unsigned int const, A * const> Container; BOOST_CLASS_TRACKING(Container, boost::serialization::track_never); std::ostream & operator<<(std::ostream & os, Container const & container) { Container::const_iterator end = container.end(); for (Container::const_iterator i = container.begin(); i != end; ++i) { os << "(" << i->first << "," << *i->second << ")" << std::endl; } return os; } int _tmain(int argc, _TCHAR* argv[]) { std::cout << "serialization map test starts" << std::endl; Container outputContainer; outputContainer.insert(std::make_pair(1, new A("one"))); outputContainer.insert(std::make_pair(4, new A("four"))); outputContainer.insert(std::make_pair(2, new A("two"))); std::cout << outputContainer << std::endl; { std::wofstream outputFile("data.txt"); boost::archive::text_woarchive outputArchive(outputFile); outputArchive << outputContainer; } std::cout << "---------------------------" << std::endl; Container inputContainer; { std::wifstream inputFile("data.txt"); boost::archive::text_wiarchive inputArchive(inputFile); inputArchive >> inputContainer; // this line causes compile error } std::cout << inputContainer << std::endl; std::cout << "serialization map test ends" << std::endl; return 0; }

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Re: [Boost-users] [Regex] regex_search
by Etienne Philip Pretorius 16 Jul '09

16 Jul '09

Never mind, I worked around the problem. Thank you, Etienne

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[Regex] regex_search
by Etienne Philip Pretorius 16 Jul '09

16 Jul '09

Hello List, I am having an issue compiling the my code - I get the following error: xml.hpp:43: error: no matching function for call to ‘regex_search(boost::asio::buffers_iterator<boost::asio::const_buffers_1, char>&, boost::asio::buffers_iterator<boost::asio::const_buffers_1, char>&, boost::match_results<boost::asio::buffers_iterator<boost::asio::const_buffers_1, char>, std::allocator<boost::sub_match<boost::asio::buffers_iterator<boost::asio::const_buffers_1, char> > > >&, boost::_bi::bind_t<boost::regex&, boost::_mfi::mf0<boost::regex&, xmpp::xml::parser>, boost::_bi::list1<boost::_bi::value<const xmpp::xml::parser*> > >, boost::regex_constants::match_flags)’ Here is the related code snippet: template <typename iterator> std::pair<iterator, bool> operator()( iterator begin, iterator end ) const { if(begin == end) { return std::make_pair(end,false); } boost::match_results<iterator> match_results; //Compiler Error Start if(boost::regex_search( begin, end, match_results, boost::bind( &parser::regex, this ), boost::match_default | boost::match_partial)) { //Compiler Error End if(match_results[0].matched) { //test return std::make_pair(match_results[0].second,true); }else{ //test return std::make_pair(match_results[0].first,false); } } return std::make_pair(end,false); }; private: boost::regex regex( ){ return XMLDecl_; }; static boost::regex S_, Eq_, EncName_, VersionInfo_, EncodingDecl_, SDDecl_, XMLDecl_, UTF8_, Char_, NameStartChar_, NameChar_, Name_, Names_, Comment_, PITarget_, PI_, Misc_, prolog_; Could someone please shed some light on this problem for me. I want to be able to change the regular expression based on a state variable so that operator() can advance to the next xml type that it should/could encounter. Thank you. Etienne

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(newbie) boost thread compile problems on Fedora 8
by Kishalay Kundu 16 Jul '09

16 Jul '09

Hi, I am having trouble compiling a correct version of the boost thread library on a x86_64 Fedora Core 8 and was wondering if anyone can help me out. I've tried both version 1.37 and 1.39. I describe below what I do and what happens after that. I am on an AMD64 Fedora Core 8 platform (with gcc 4.1.2 and glibc 2.7) that already had boost 1.34 on it at /usr/lib level. I erased that version by deleting all the libraries and moving 'boost' directory in /usr/include to 'boost_1-34' directory. I download the .gz tarball, bootstrap it, make it (with make for 1.37 and bjam for 1.39) and install it to /usr/local/lib. The compilation goes without a hitch (except for some warnings for boost serialization and others, but not for thread). I have both .a and .so files generated and residing in /usr/local/lib and boost include files in /usr/local/include. I add the links libboost_thread-mt.a and libboost_thread-mt.so to point to libboost_thread-gcc41-mt_1.3x.* libs. Now, I write a small test program (given below). It gives me linker errors with undefined references to pretty much every pthread symbol. If anyone wants I can paste all the errors in the next message. When I add the -lpthread flag to the compile, it gives me an undefined reference error with regards to __vdso_clock_gettime from /lib64/libpthread.a. I'm not sure where exactly the problem lies and would greatly appreciate if someone could point me in the right direction. Thank you. regards, Kishalay My test program: compiled with: gcc -o testk test.cpp -lboost_thread-mt #include <cstdio> #include <cstdlib> #include <boost/thread.hpp> using namespace std; using namespace boost; static void somefunc( ) { printf( "thread calling this\n" ); } int main( int argc, char** argv ) { boost::thread* t = new thread( somefunc ); delete t; }

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boost 1.39 hp-ux support dropped ?
by Avi Bahra 16 Jul '09

16 Jul '09

It appears that boost 1.37, 1.38 all support HP-UX as a primary compiler. However 1.39 release notes, make no mention of HP-UX at all? is this deliberate or an oversight? Best regards, Ta, Avi

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[serialization][python] (ab)using serialization to read/write object attribute values from python
by Václav Šmilauer 16 Jul '09

16 Jul '09

Hello boosters, I am working on http://yade.wikia.com project and we plan to switch to boost::serialization. boost::python is already used (many thanks for that fantastic piece of code). Let me explain the current state first. We use custom serialization interface: each class registers various attributes of objects; at serialization, archive of pointers to the attributes associated with attribute names is created and serialized to XML (and vice versa for deserialization). Boost.python is used to wrap c++ objects in python. Each wrapper class defined __getattr__ and __setattr__; if called, the wrapper: 1. Checks that the underlying c++ object has an associated archive of attributes created. 2. Gets/sets the value of the attribute based on its registered name (because of current limitations, the value is passed to the archive as string) The advantage is that there is no need to wrap every single class in python, just a few top-level classes; and access to all other attributes of the derived types is automatically provided by the serialization framework. My questions are: 1. Do boost::serialization archives keep pointers to attributes, in such way that it is possible to keep one archive instance per object and use it to write an attribute continuously, with the change being immediately propagated to the c++ objects, and ask the archive for attribute value based on its name? 2. Is it possible (or has it even been done) to define python_iarchive and python_oarchive that would (de)serialize between python and c++ types (such as std::map to dicitonary, [] to vector etc.)? I am sorry if those questions are trivial or nonsensical... I am trying to foresee problems that we could have with boost::serialization. If you have some proposition how to solve this xml+python attribute access in a better unified way, don't hesitate to post, please. (Switching the wrapper to py++ doesn't seem very practical at the moment, as it works quite nicely the current way; (frequent) adding of a class or adding/removing attributes doesn't require the wrapper to be regenerated/recompiled at all) Regards, Václav Šmilauer

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Building boost faster: /MP
by Robert Dailey 16 Jul '09

16 Jul '09

Hello, I'm sure most of you are aware of the /MP flag introduced in MSVC9. I know this flag works fine when set through Visual Studio 9, however, I'm not sure if it works when calling cl.exe directly. Since it's just a compiler flag I imagine it does. It would be great to see support for this flag in CMake and/or bjam to help build boost faster when using this particular compiler. Any thoughts on this? Sincerely, Robert Dailey

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A question on C++ DLL making in Dev-C++.Can anyone with kindness help me?
by fmingu 16 Jul '09

16 Jul '09

I am using Dev-C++ 4.9.8.0. I tried to make DLLs in Dev-C++. Can anyone with kindness tell me where can I get the help materials on making classes in a DLL and use the member functions in my executables? I found many materials spoke on the functions in DLL but few of them spoke on the member functions and classes in DLL. Although the platform gives the skeleton of a C++ DLL,i.e. dllmain.cpp, dll.h,I can not understand it. The help files in Dev-C++ did not explain it explicitly. Maybe a step_by_step turial is useful. I know that is not quite appropriate to ask such question in this area. But after several days of asking problems, I found there are lots of experts here. And I am just a new comer in programing. Does someone know the format of DLL made from Dev-C++ ? Coff or omf ? Can the DLL be applied by Borland C++ builder 2009? If not, how can I handle it? Can the DLL be compatible with Visual C++? Thanks a lot.

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Re: [Boost-users] Unable to catch exception using boost::asio
by Alex Black 15 Jul '09

15 Jul '09

> > Message: 3 > Date: Wed, 15 Jul 2009 10:56:22 -0500 > From: Zachary Turner <divisortheory(a)gmail.com> > Subject: Re: [Boost-users] Unable to catch exception using boost::asio > To: boost-users(a)lists.boost.org > Message-ID: > <478231340907150856x12c9fd92w3b06630d349eef36(a)mail.gmail.com> > Content-Type: text/plain; charset=ISO-8859-1 > > > I wrapped my call to run() in a try-catch, no luck, no exception > > appears to be being thrown by io_service.run(). > > > > void CBaseWebServer::RunIoService() > > { > > ? ? ? ?try > > ? ? ? ?{ > > ? ? ? ? ? ? ? ?m_IoService.run(); > > ? ? ? ?} > > ? ? ? ?catch ( ... ) > > ? ? ? ?{ > > ? ? ? ? ? ? ? ?cout << "Unhandled exception in > RunIoService"; ? ? ? ?} > > } _______________________________________________ > > Boost-users mailing list > > Boost-users(a)lists.boost.org > > http://lists.boost.org/mailman/listinfo.cgi/boost-users > > > > > That probably won't help. Notice that > CBaseWebServer::RunIoService() is not in the call stack at > the point you're seeing the exception. > After looking at your callstack again, I believe you're > throwing from a destructor. In particular, notice in your > callstack that you have > this: > > 26 ~ProtoBufStreamAdaptor() /home/noirs/workspace/myfile2.cpp:10 > 0x000000000042c6e5 > 25 CWebServer::HandleGetNeighbors() > /home/noirs/workspace/myfile3.cpp:215 0x000000000041d2d8 > > > These appear to both be in your own code. My suspicion is > that an exception occurs in CWebServer::HandleGetNeighbors(), > which causes it to unwind the stack and execute destructors. > In particular a destructor for an object of type > ProtoBufStreamAdaptor() is called, and this destructor then > throws another exception. At this point your program will > definitely terminate immediately. > > First check the destructor of ProtoBufStreamAdaptor() to see > why it's throwing (destructors should _never_ throw under any > circumstances), and then check the code of > CWebServer::HandleGetNeighbors() to find the original error. Thanks for continuing to help with this. I had the same thoughts as you, and I've looked into that with no luck. For example, here is the code for ~ProtoBufStreamAdaptor(): ProtoBufStreamAdaptor::~ProtoBufStreamAdaptor(void) {} The original error is related to the client (on the other end of the socket) being interrupted. Presumably some socket operation is throwing an exception, e.g. I'm writing to the socket after the client has disconnected. You mentioned never throwing exceptions in destructors - sounds like good advice, thx. Two points though: 1. If an exception is thrown in a destructor can it not be caught with a try catch( ... )? 2. I'll look over the code more closely and see if there are any destructors throwing.

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Serialization on boost::dynamic bitset
by Gokulakannan Somasundaram 15 Jul '09

15 Jul '09

Hi, I have to write code for serialization of dynamic bitset. I could well write the code by iterating through the bitset, but i was just wondering, why it is not provided as part of the library. Thanks, Gokul.

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using bjam to build multi thread library for visual studio 2003
by mike_wilson 15 Jul '09

15 Jul '09

Hi, I am trying to build the multi thread library for visual studio 2003. I built the bjam exe and run the following. bjam toolset=msvc-7.1 variant=debug threading=multi link=shared but I am returned C:\boost>bjam toolset=msvc-7.1 variant=debug threading=multi link=shared C:/boost/tools/build/v2/tools\msvc.jam:734: in configure-really *** argument error * rule path.make ( native ) * called with: ( ) * missing argument native C:/boost/tools/build/v2/util\path.jam:44:see definition of rule 'make' being called C:/boost/tools/build/v2/tools\msvc.jam:184: in configure C:/boost/tools/build/v2/tools\msvc.jam:137: in msvc.init C:/boost/tools/build/v2/build\toolset.jam:38: in toolset.using C:/boost/tools/build/v2/build\project.jam:862: in using C:\boost\tools/build/v2\user-config.jam:59: in modules.load C:/boost/tools/build/v2\build-system.jam:241: in load-config C:/boost/tools/build/v2\build-system.jam:383: in load-configuration-files C:/boost/tools/build/v2\build-system.jam:520: in load C:\boost\tools\build\v2/kernel\modules.jam:283: in import C:\boost\tools\build\v2\kernel\bootstrap.jam:138: in boost-build C:\boost\boost-build.jam:18: in module scope My bjam version is C:\boost>bjam --version Boost.Build V2 (Milestone 12) Boost.Jam 03.1.17 and my boost library version is 1.38. My boost library is in c:\boost so no spaces present in directory paths. Thanks for any advice. -- View this message in context: http://www.nabble.com/using-bjam-to-build-multi-thread-library-for-visual-s… Sent from the Boost - Users mailing list archive at Nabble.com.

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boost mutex locks
by mike_wilson 15 Jul '09

15 Jul '09

Hi, I am a newbie to C++ multi threading (did a bit in java) and would like for information on the following... consider:- class MyClass { void SetMyObject(SomeClass const& value) { boost::mutex::scoped_lock lock(objectMutex); myObject = value; } SomeClass SetMyObject() const { boost::mutex::scoped_lock lock(objectMutex); return myObject; } private: SomeClass myObject; boost::mutex objectMutex; }; Say one thread accesses the SetMyObject() , given that there is a lock in the function, it will also lock the GetMyObject() blocking any other thread from calling? This kind of implies that wherever in the object there is a lock, any function owned by the object will be locked to any other thread trying to access. Is this correct? Thanks again for your help. -- View this message in context: http://www.nabble.com/boost-mutex-locks-tp24406812p24406812.html Sent from the Boost - Users mailing list archive at Nabble.com.

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Re: [Boost-users] Unable to catch exception using boost::asio
by Alex Black 15 Jul '09

15 Jul '09

(Response below) > > Alex Black wrote: > > (Response is below) > > > > > >> On Tue, Jul 14, 2009 at 7:49 PM, Alex > Black<alex(a)alexblack.ca> wrote: > >>>>> I'm using boost::asio for sockets, writing a response out to a > >>> client. > >>>>> If the client stops part way through getting the > >> response, then my > >>>>> server process dies: > >>>>> > >>>>> terminate called after throwing an instance of > >>>>> > >> > 'boost::exception_detail::clone_impl<boost::exception_detail::error_in > >>>>> fo_injector<boost::system::system_error> > >>>>>> ' > >>>>> ? what():? Broken pipe > >>>>> > >>>>> The code though is surrounded by try catch like this: > >>>>> > >>>>> try > >>>>> { > >>>>> ??? ... > >>>>> } > >>>>> catch ( std::exception& e ) > >>>>> { > >>>>> ??? cout << e.what() << endl; > >>>>> } > >>>>> catch ( ... ) > >>>>> { > >>>>> ???? cout << "unexpected exception" << endl; } > >>>>> > >>>>> How do I prevent my process from aborting/terminating like this? > >>> v > >>> > >>>> Have you verified that the code inside the try block > executes on the > >>> same thread that the exception is occuring in? > >>> > >>> Not explicitly, how would I do that? > >>> > >>> thx > >>> > >> First put a breakpoint inside the try block. When it gets > >> hit use whatever mechanism your debugger provides to see what > >> thread you're in. In windows using MSVC, for example, you'd > >> just add a watch for a variable called $TID which a special > >> pseudo-variable that shows you the thread id. For other > >> debuggers you'd have to consult the manual. > >> Next register an unhandled exception handler. > >> > >> #include <exception> > >> > >> void unhandled_exception_handler() > >> { > >> std::cout << "Got an unhandled exception!" << std::endl; } > >> > >> int main(int argc, char** argv) > >> { > >> std::set_terminate(unhandled_exception_handler); > >> > >> //rest of your program. > >> } > >> > >> Then put a breakpoint inside unhandled_exception_handler and > >> when it gets hit walk up the callstack in the debugger to see > >> where the exception is occuring. In addition you can > >> determine the thread id again using the same method you used > >> in the first step. My guess is that they're not in the same > >> thread. I'm not sure if it applies to your scenario, but > >> remember that the operation's completion handler is invoked > >> on is not necessarily the same thread that the request is > >> issued on depending on how you're using the io_service > >> object. So while you have a try {} catch(...) {} in the > >> completion handler, if the exception is on the other thread > >> that does you no good. > >> > > > > Thanks for the tip, I didn't know about set_terminate, I made that > > change. > > > > I put a breakpoint in my terminate handler, and the callstack looks > > like: > > > > 32 unhandled_exception_handler() /home/noirs/workspace/myfile.cpp:35 > > 0x0000000000438764 > > 31 <symbol is not available> 0x00007f9ceb0d04b6 > > 30 <symbol is not available> 0x00007f9ceb0cf6ab > > 29 __gxx_personality_v0() 0x00007f9ceb0d0278 > > 28 <symbol is not available> 0x00007f9ceab7cff3 > > 27 _Unwind_Resume() 0x00007f9ceab7d0b8 > > 26 ~ProtoBufStreamAdaptor() /home/noirs/workspace/myfile2.cpp:10 > > 0x000000000042c6e5 > > 25 CWebServer::HandleGetNeighbors() > > /home/noirs/workspace/myfile3.cpp:215 0x000000000041d2d8 > > 24 CWebServer::OnHttpRequest() /home/noirs/workspace/myfile3.cpp:89 > > 0x000000000041e790 > > 23 CBaseWebServer::HandleHTTPRequest() > > /home/noirs/workspace/myfile4.cpp:92 0x00000000004092ef > > 22 CBaseWebServer::HandleAccept() > /home/noirs/workspace/myfile4.cpp:61 > > 0x0000000000409a9e > > > > HandleAccept looks like: > > > > void CBaseWebServer::HandleAccept(shared_ptr<tcp::socket> > pSocket, const > > boost::system::error_code& error) > > { if ( !error ) > > { > > try > > { > > HandleHTTPRequest(pSocket); > > > > StartAccept(); > > } > > catch ( ... ) > > { > > cout << "Unhandled exception in HandleAccept"; > > } > > } > > else > > { > > cout << "HandleAccept received error: " << > > error.message().c_str() << endl; > > } > > } > > _______________________________________________ > > Boost-users mailing list > > Boost-users(a)lists.boost.org > > http://lists.boost.org/mailman/listinfo.cgi/boost-users > > Um, broken pipe = closed file desciptor. > > Check if the socket is actually valid in the shard_ptr... > > BTW, are you using Async operations.... if so then the exception will > not originate from your code but from io_service.run(). I wrapped my call to run() in a try-catch, no luck, no exception appears to be being thrown by io_service.run(). void CBaseWebServer::RunIoService() { try { m_IoService.run(); } catch ( ... ) { cout << "Unhandled exception in RunIoService"; } }

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[statechart] Substates in dll
by Bill Clark 15 Jul '09

15 Jul '09

Is there any way to partition a state machine using boost::statechart such that the main state machine is in one dll, and its substates (and possibly their substates) are in separate dll's? It would seem that this would create a cyclic dependency. Suppose you have e.g. a simple statechart called MyStatechart containing an initial state State1 which transitions to State2 in response to some event. Is it possible to implement MyStatechart and State1 in MyStatechart.dll, and State2 in State2.dll? Since the code for State1 will need to reference State2 (in order to transition to it), MyStatechart.dll will have a dependency on State2.dll. But since State2 is contained in MyStatechart, its type will have to look something like struct State2: sc::state<State2, MyStatechart> { //... }; which means that State2.dll will have a dependency on MyStatechart.dll. Is it possible to avoid this cycle? Thanks for any help, Bill

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Re: [Boost-users] Unable to catch exception using boost::asio
by Alex Black 15 Jul '09

15 Jul '09

(Response is below) > On Tue, Jul 14, 2009 at 7:49 PM, Alex Black<alex(a)alexblack.ca> wrote: > >>> I'm using boost::asio for sockets, writing a response out to a > > client. > >>> > >>> If the client stops part way through getting the > response, then my > >>> server process dies: > >>> > >>> terminate called after throwing an instance of > >>> > > > 'boost::exception_detail::clone_impl<boost::exception_detail::error_in > >>> fo_injector<boost::system::system_error> > >>>>' > >>> ? what():? Broken pipe > >>> > >>> The code though is surrounded by try catch like this: > >>> > >>> try > >>> { > >>> ??? ... > >>> } > >>> catch ( std::exception& e ) > >>> { > >>> ??? cout << e.what() << endl; > >>> } > >>> catch ( ... ) > >>> { > >>> ???? cout << "unexpected exception" << endl; } > >>> > >>> How do I prevent my process from aborting/terminating like this? > > v > > > >>Have you verified that the code inside the try block executes on the > > same thread that the exception is occuring in? > > > > Not explicitly, how would I do that? > > > > thx > > > > First put a breakpoint inside the try block. When it gets > hit use whatever mechanism your debugger provides to see what > thread you're in. In windows using MSVC, for example, you'd > just add a watch for a variable called $TID which a special > pseudo-variable that shows you the thread id. For other > debuggers you'd have to consult the manual. > Next register an unhandled exception handler. > > #include <exception> > > void unhandled_exception_handler() > { > std::cout << "Got an unhandled exception!" << std::endl; } > > int main(int argc, char** argv) > { > std::set_terminate(unhandled_exception_handler); > > //rest of your program. > } > > Then put a breakpoint inside unhandled_exception_handler and > when it gets hit walk up the callstack in the debugger to see > where the exception is occuring. In addition you can > determine the thread id again using the same method you used > in the first step. My guess is that they're not in the same > thread. I'm not sure if it applies to your scenario, but > remember that the operation's completion handler is invoked > on is not necessarily the same thread that the request is > issued on depending on how you're using the io_service > object. So while you have a try {} catch(...) {} in the > completion handler, if the exception is on the other thread > that does you no good. > Thanks for the tip, I didn't know about set_terminate, I made that change. I put a breakpoint in my terminate handler, and the callstack looks like: 32 unhandled_exception_handler() /home/noirs/workspace/myfile.cpp:35 0x0000000000438764 31 <symbol is not available> 0x00007f9ceb0d04b6 30 <symbol is not available> 0x00007f9ceb0cf6ab 29 __gxx_personality_v0() 0x00007f9ceb0d0278 28 <symbol is not available> 0x00007f9ceab7cff3 27 _Unwind_Resume() 0x00007f9ceab7d0b8 26 ~ProtoBufStreamAdaptor() /home/noirs/workspace/myfile2.cpp:10 0x000000000042c6e5 25 CWebServer::HandleGetNeighbors() /home/noirs/workspace/myfile3.cpp:215 0x000000000041d2d8 24 CWebServer::OnHttpRequest() /home/noirs/workspace/myfile3.cpp:89 0x000000000041e790 23 CBaseWebServer::HandleHTTPRequest() /home/noirs/workspace/myfile4.cpp:92 0x00000000004092ef 22 CBaseWebServer::HandleAccept() /home/noirs/workspace/myfile4.cpp:61 0x0000000000409a9e HandleAccept looks like: void CBaseWebServer::HandleAccept(shared_ptr<tcp::socket> pSocket, const boost::system::error_code& error) { if ( !error ) { try { HandleHTTPRequest(pSocket); StartAccept(); } catch ( ... ) { cout << "Unhandled exception in HandleAccept"; } } else { cout << "HandleAccept received error: " << error.message().c_str() << endl; } }

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[Bind] Does not compile with local classes
by Rudi Dittrich 15 Jul '09

15 Jul '09

Hello, I tried to use a local class as a callback function registering with a boost signal. The example below shall illustrate this scenario. There are two classes: class Foo which triggers a signal when its member function set_k( k ) is called. Each object which wants to receive this signal has to subscribe with it, calling on_k_changed(...). The second class is Bar which has one member function change_k(...). There is a local class KChanged inside this member function. KChanged has one function k_changed(...) which shall be called whenever the signal in Foo is triggered. Thus, it shall act as a callback function. Therefore, I used boost bind with k_changed(...) and tried to register with Foo's signal. After compiling I get the following compilation error: g++ -Wall -o local_class local_class.cpp -lboost_signals In member function ‘void Bar::change_k(uint32_t)’: nested_function.cpp:56: error: no matching function for call to ‘bind(void (Bar::change_k(uint32_t)::KChanged::*)(uint32_t), Bar::change_k(uint32_t)::KChanged*, boost::arg<1>&)’ I do not really understand why this doesn't work. If I make k_changed(...) static then it works and I do not get any compilation errors. So my questions are: 1.) Is this a compiler problem? I use g++ (GCC) 4.1.2 20080704 (Red Hat 4.1.2-44) 2.) Or is such a construct not supported by the C++ language in general? 3.) Or is boost bind not able to handle local classes. 4.) And if it is possible to use bind with local functions how, do I have to implement it? I would really appreciate if somebody could help me. Best regards, Rudolf Dittrich. #include <iostream> #include <boost/bind.hpp> #include <boost/signals.hpp> typedef boost::signals::connection connection_t; class Foo { public: private: typedef boost::signal<void (uint32_t)> sig_k_t; sig_k_t _sigK; public: Foo() {} ~Foo() {} connection_t on_k_changed( const sig_k_t::slot_function_type& subscriber ) { return _sigK.connect( subscriber ); } void disconnect( connection_t subscriber ) { subscriber.disconnect(); } void set_k( uint32_t k ) { _sigK( k ); } }; class Bar { private: Foo& _foo; public: Bar( Foo& foo ) : _foo( foo ) {} void change_k( uint32_t k ) { static uint32_t k_new; struct KChanged { void k_changed( uint32_t k ) { k_new = k; } } k_changed; connection_t conn; conn = _foo.on_k_changed( boost::bind( &KChanged::k_changed, &k_changed, _1 ) ); _foo.set_k( k ); _foo.disconnect( conn ); } }; int main( int argc, char *argv[] ) { Foo foo; Bar bar( foo ); bar.change_k( 100 ); return 0; } -- Jetzt kostenlos herunterladen: Internet Explorer 8 und Mozilla Firefox 3 - sicherer, schneller und einfacher! http://portal.gmx.net/de/go/chbrowser

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[boost][graph] update adjacency_list from boost 1.33 to 1.39
by Andrey Torba 15 Jul '09

15 Jul '09

I update boost in a project from 1.33 to 1.39. In elier boost.graph adjacency_list had last template parameter 'Allocator'. Now this parameter is abcent. The question is how was it used? In my example there is a Graph type: typedef boost::adjacency_list<list_pooledS, list_pooledS, boost::directedS, NodeInfo, EdgeInfo, boost::no_property, list_pooledS, * boost::get_mat_fast_pool_alloc<char>::allocator*> Graph; as i can see allocator is defined in `list_pooledS`. Will it be enough to define such type (without last parameter)? typedef boost::adjacency_list<list_pooledS, list_pooledS, boost::directedS, NodeInfo, EdgeInfo, boost::no_property, list_pooledS> Graph; -- Regards, Andrey

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[boost][thread] Breaking Changes
by Andrey Torba 15 Jul '09

15 Jul '09

Hi all! One of breaking changes of boost.thread since 1.34 are changes in the scoped_lock interface: was: boost::mutex::scoped_lock some_lock(some_mutex,false); now: boost::mutex::scoped_lock some_lock(some_mutex,boost::defer_lock); I update boost. So i have many methods in a project which accepts a boolean variable initial_lock. void c::fff(bool initial_lock) { scoped_lock lk(m_mutex, initial_lock); // do fff .... } Now it's impossible because of different types: const defer_lock_t defer_lock={}; const try_to_lock_t try_to_lock={}; const adopt_lock_t adopt_lock={}; For example if with boost 1.33 method looked like: void c::fff(bool initial_lock) { scoped_lock lk(m_mutex, initial_lock); // do fff .... } what kind of refactoring should i do? to pass locking strategy as a template parameter? template<class Lock> void c::fff(Lock initial_lock) { scoped_lock lk(m_mutex, initial_lock); invoke_fff(); } What was the reason to have a different locking types and not enum{defer_lock, try_to_lock, adopt_lock}. Does aproach lead to any errors? -- Regards, Andrey

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Boost Unordered Map
by Wong Peter 15 Jul '09

15 Jul '09

Hello to all, does boost unordered map have a member function called find and after the key, i would manipulate the value in the hash table. Thanks. -- Linux

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[Pool] questions
by Pearl Rothman 15 Jul '09

15 Jul '09

I am using Fedora 9, gcc 4.3.0, and boost 1.38.0. I am inheriting from object_pool so I have access to some of object_pool's hidden members. Is there a way for me to find out how many memory blocks or allocated chunks there are in the free list vs how many chunks are currently being used? Is the object_pool thread safe? Does set_next_size have a permanent effect or will the double algorithm start being used after the next allocation? If it's a permanent effect, is there something I can call to start using the double algorithm again? Thanks

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Portable Approach to get System Time
by Wong Peter 15 Jul '09

15 Jul '09

Hello to all, What is the portable approach to get the current system time ? Thanks. -- Linux

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Boost Function
by Wong Peter 15 Jul '09

15 Jul '09

What is Boost::function ? I read the documentation but cann;t find any clear explanation. -- Linux

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boost bind example does not compile with member template function on gcc 4.0
by James Pritts 15 Jul '09

15 Jul '09

Unfortunately I cannot grok boost::bind error, but this code seems really simple. If I change the code so that an int is passed to async_discovery, the program compiles. The problem seems to be centered around passing a boost::bind as a template argument. Any help would be appreciated. Here is the code... #include <boost/bind.hpp> class antix_discovery_service { public: template <typename Handler> void start_async_discovery(Handler handler) { } /// Asynchronously resolve a query to a list of entries. template <typename Handler> void async_discovery(Handler handler) { boost::bind(&antix_discovery_service::template start_async_discovery<Handler>, this, handler)(); } private: int ttt; }; class test { public: void do_it() { } }; int main() { antix_discovery_service ads; test t; ads.async_discovery(boost::bind<void>(&test::do_it, t)); return 0; } and here is the error... main.cpp: In function 'int main()': main.cpp:33: warning: unused variable 'jjj' ../vendor/boost/boost/bind/bind.hpp: In member function 'void boost::_bi::list2<A1, A2>::operator()(boost::_bi::type<void>, F&, A&, int) [with F = boost::_mfi::mf1<void, antix_discovery_service, boost::_bi::bind_t<void, boost::_mfi::mf0<void, test>, boost::_bi::list1<boost::_bi::value<test> > > >, A = boost::_bi::list0, A1 = boost::_bi::value<antix_discovery_service*>, A2 = boost::_bi::bind_t<void, boost::_mfi::mf0<void, test>, boost::_bi::list1<boost::_bi::value<test> > >]': ../vendor/boost/boost/bind/bind_template.hpp:20: instantiated from 'typename boost::_bi::result_traits<R, F>::type boost::_bi::bind_t<R, F, L>::operator()() [with R = void, F = boost::_mfi::mf1<void, antix_discovery_service, boost::_bi::bind_t<void, boost::_mfi::mf0<void, test>, boost::_bi::list1<boost::_bi::value<test> > > >, L = boost::_bi::list2<boost::_bi::value<antix_discovery_service*>, boost::_bi::bind_t<void, boost::_mfi::mf0<void, test>, boost::_bi::list1<boost::_bi::value<test> > > >]' main.cpp:14: instantiated from 'void antix_discovery_service::async_discovery(Handler) [with Handler = boost::_bi::bind_t<void, boost::_mfi::mf0<void, test>, boost::_bi::list1<boost::_bi::value<test> > >]' main.cpp:35: instantiated from here ../vendor/boost/boost/bind/bind.hpp:306: error: invalid use of void expression ...failed gcc.compile.c++ ..\.bin\test_bind\gcc-4.0\debug\main.o... ...skipped <p..\.bin\test_bind\gcc-4.0\debug>test_bind.avc for lack of <p..\.bin\test_bind\gcc-4.0\debug>main.o... ...skipped <p..\.bin\test_bind\gcc-4.0\debug>test_bind.ix86-win32.elf for lack of <p..\.bin\test_bind\gcc-4.0\debug>test_bind.avc... ...skipped <pinstall>test_bind.ix86-win32.elf for lack of <p..\.bin\test_bind\gcc-4.0\debug>test_bind.ix86-win32.elf... ...failed updating 1 target... ...skipped 3 targets... Compilation exited abnormally with code 1 at Tue Jul 14 14:27:58 -Jimmy.

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Re: [Boost-users] [statechart] friend state can't call overloaded member functions in machine class
by David Matz 15 Jul '09

15 Jul '09

Hello Andreas, [snip] Replace with the following lines and everything should work: > > sc::in_state_reaction< EvBack, CoreApp, (void (CoreApp::*)(const EvBack &)) > &CoreApp::doInStateReaction >, > sc::in_state_reaction< EvNext, CoreApp, (void (CoreApp::*)(const EvNext &)) > &CoreApp::doInStateReaction > Yes, thats what I'm looking for. Now it compiles. Thanks a lot :-) David

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[program options] vectro from config file
by Diederick C. Niehorster 15 Jul '09

15 Jul '09

Hi All, I can't find an answer to this before, so I'll ask here. I would like to read a vector from a config file using program_options. example definition of option: ("Expt.ControlOrd", po::value<vector<int>>(&_pcData->SetExptOrders()), "Expt.ControlOrd") In the config file, the following works: ControlOrd = 1 ControlOrd = 2 But i would much prefer to use: ControlOrd = 1 2 or ControlOrd = (1 2) or something like that. I have made this work by editing the sourcecode, diff: ---- Index: config_file.cpp =================================================================== --- config_file.cpp (revision 54915) +++ config_file.cpp (working copy) @@ -12,6 +12,8 @@ #include <boost/program_options/detail/convert.hpp> #include <boost/throw_exception.hpp> +#include <boost/algorithm/string.hpp> + #include <iostream> #include <fstream> #include <cassert> @@ -112,8 +114,17 @@ found = true; this->value().string_key = name; this->value().value.clear(); - this->value().value.push_back(value); this->value().unregistered = !registered; + + if (*value.begin() == '(' && *value.rbegin() == ')') + { + value = value.substr(1, value.size()-2); + vector<string> SplitVec; + split( SplitVec, value, is_any_of(" ") ); + this->value().value.swap(SplitVec); + } + else + this->value().value.push_back(value); break; } else { ---- Of course, this is not a great solution as it doesn't allow you to read strings starting with ( and ending with ). Well, it is missing one thing. If we could somehow check that the datatype requested for this options is a vector, we could add that check to the if. I think that leaves only one problem, that of reading a vector of strings. Please tell me if it is possible to check for the requested type at this point in the code and how to do it. Any other comments also very welcome! I'll suggest it to the author once it works well. Thank you, Diederick

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