January 2009 - Boost-users - lists.boost.org

[BGL] Segfaults when switching from digraph to undirected graph
by Grzegorz Slodkowicz 28 Jan '09

28 Jan '09

Hi, I ran into trouble after changing my directed adjacency_list into an undirected graph. The following code causes a segfault: for (set<Node>::iterator n = nodes.begin(); n != nodes.end(); ++n) { graph_traits<Graph>::out_edge_iterator edges_begin, edges_end; tie(edges_begin, edges_end) = out_edges(*n, g); for (graph_traits<Graph>::out_edge_iterator ne = edges_begin; ne != edges_end; ++ne) { Node nn1 = target(*ne, g); // ... K_o = out_degree(nn1, g); graph_traits<Graph>::out_edge_iterator nn1edges_begin, nn1edges_end; tie(nn1edges_begin, nn1edges_end) = out_edges(nn1, g); int k; graph_traits<Graph>::out_edge_iterator nn1e; for (nn1e = nn1edges_begin; nn1e != nn1edges_end; ++nn1e) { k = 0; if (nodes.count(target(*nn1e, g))) // !!! k++; } } } I cut out most of the stuff not directly related to accessing the graph. It segfaults in the line marked by !!!, so it would seem that out_edges returns an invalid range (I did some debugging and the this line executes quite a few times before the iterator becomes invalid. I can't seem to force gdb to recognise nn1e as a symbol so I can't tell which edge/node is causing the problem. All this is ran after the graph is initialised (it's quite large, ab. 22k nodes and 900k edges). Best regards, Greg

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multi_index: changing elements?
by Olaf Leidinger 28 Jan '09

28 Jan '09

Hello! I'm quiet new to boost and especially multi_index. I want to get a non-constant reference to elements I inserted into this container, but when dereferencing the iterator all I get is a const reference. What am I doing wrong? Please have a look at the attached example. Thanks a lot, Ciao, Olaf Leidinger

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Howto check Matrix Byte Size in Boost's Ublas Object
by Gundala Viswanath 28 Jan '09

28 Jan '09

Dear All, I have the following matrix implementation using Ublas. One is plain old matrix ('m') and the other is sparse matrix ('sm') My question is how can I check the byte size of 'sm' and 'm'? If my implementation is correct 'sm' byte size should give much smaller byte size than 'm'. Since both 'm' and 'sm' print the same output here. //____ BEGIN__ matrix<double> m(matDim[0], matDim[1], 0); coordinate_matrix<double> sm(matDim[0],matDim[1], 0); for (size_t i = 0; i < realValue.size(); ++i){ m(rowIndex[i]-1,colIndex[i]-1) = realValue[i]; sm(rowIndex[i]-1,colIndex[i]-1) = realValue[i]; } // End The full and compilable code can be found here: http://cpp.codepad.org/MbPm3OuK - Gundala Viswanath Jakarta - Indonesia

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[asio] still weird crashes with asio using libpion on windows
by Stephan Menzel 28 Jan '09

28 Jan '09

Hi all, I have been experiencing problems with weird crashes on Windows using libpion (http://www.pion.org/projects/pion-network-library) and the problem is still there with pion 1.0.10 but it changed a little and might shed some new light on the Let me just outline the situation. I have a simple project with an app and two libs, both using boost 1.36 at this time. The app links against those two libs, and one of the libs links against pion. So does the app of course. I've built pion as debug dll with boost 1.36. This runs on Windows and Linux. Now on Linux everything is fine, no problem at all, no dangerous valgrind output, nothing. On Windows however, the application crashes as soon as I do something with pion, and the callstack leads me to believe it's got something to do with boost asio. Usually it happens within asio win_mutex and looks a lot like this: http://trac.atomiclabs.com/ticket/32 To me this looks like an uninitialized mutex is being used. Not entirely however. I get this: First-chance exception at 0x7c91100b in myapp.exe: 0xC0000005: Access violation reading location 0x00000028. it's in win_mutex.hpp int do_lock() { #if defined(__MINGW32__) // Not sure if MinGW supports structured exception handling, so for now // we'll just call the Windows API and hope. ::EnterCriticalSection(&crit_section_); return 0; #else __try { -> ::EnterCriticalSection(&crit_section_); // CRASH } __except(GetExceptionCode() == STATUS_INVALID_HANDLE || GetExceptionCode() == STATUS_NO_MEMORY ? EXCEPTION_EXECUTE_HANDLER : EXCEPTION_CONTINUE_SEARCH) { if (GetExceptionCode() == STATUS_NO_MEMORY) return ERROR_OUTOFMEMORY; return ERROR_INVALID_HANDLE; } return 0; #endif } This exception repeats many times until eventually the app crashes because 'this' is invalid, pointing somewhere it shouldn't. The Bug occurs several seconds after the application has started, but I don't have to actually access pion's http socket for that. I think it might not be pion's fault at all. The whole thing only happens on Windows and renders both pion useless on that system. I know, it's only Windows but I've been debugging around that for some months now and I'd really like that solved at some point. Any ideas? Thanks a lot... Stephan PS: I can't go to boost 1.37 because of: https://svn.boost.org/trac/boost/ticket/2541 With Chris apparently not responding or posting about ASIO any more is there any chance of this being fixed in the next release? Is ASIO maintained at all? Cause nobody seems to care about that bug. Again, I know it's only Windows but as long as Windows is officially a supported system an imporant lib like ASIO should work on it.

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Regex & Multiple Iterations in single string?
by John D 28 Jan '09

28 Jan '09

Hi I am building something that does multiple random search and replaces across a single text file read line by line. This is just underway and already a snag. I need to know if there is a lightweight to identify and as important handle multiple regex matches in a single string. >From what I am aware BOOST_REGEX_MATCH_EXTRA exists but adds overhead and is maybe overkill. Anyone know how I can run a regex of "e" on "ececece" and deal with the 4 occurences on an individual basis. Much thanks to you all keep up the hard work, John

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Re: [Boost-users] Boost and K-Cuts
by Gianni Loiacono 27 Jan '09

27 Jan '09

Thanks Mr. Zeljko Vrba for the help and for the link :) :) Now I'm reading some docs to understand if the k-way is the best solution for my project ;) Thanks another time. Bye.

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Example program that fails to compile (boost::bind and boost::function called for collection)
by Archie14 27 Jan '09

27 Jan '09

Below is a a test program with the purpose of calling member function for each element of the collection. Argument of this member function is a boost::function. I put compilation error after the source code. Any help will be greatly appreciated. #include <boost/bind.hpp> #include <boost/function.hpp> #include <boost/ptr_container/ptr_vector.hpp> typedef boost::function<void (int, int, const char*) > delegate; class A : public boost::noncopyable { public: commandhandler(delegate& f) {} }; template <typename C> class Acoll { typedef boost::ptr_vector<C> ptr_container; ptr_container m_data; public: typedef C CLIENT; ptr_container& operator() (){return m_data;} }; template <typename CLIENTS> class Test { CLIENTS& m_clients; public: delegate dosomething; Test(CLIENTS& val) : m_clients(val) {} void run() { std::for_each(m_clients().begin(), m_clients().end(), boost::bind(&CLIENTS::CLIENT::commandhandler, boost::ref(dosomething), _1 )); } }; int _tmain(int argc, _TCHAR* argv[]) { Acoll<A> coll; Test<Acoll<A> > test(coll); test.run(); return 0; } Error: 1>e:\libraries\boost\boost_1_37_0\boost\bind.hpp(292) : error C2664: 'R boost::_mfi::mf1<R,T,A1>::operator ()<boost::function<Signature>>(const U &,A1) const' : cannot convert parameter 2 from 'A' to 'boost::function<Signature> ' 1> with 1> [ 1> R=void, 1> T=A, 1> A1=delegate &, 1> Signature=void (int,int,const char *), 1> U=delegate 1> ] 1> and 1> [ 1> Signature=void (int,int,const char *) 1> ] 1> e:\libraries\boost\boost_1_37_0\boost\bind\bind_template.hpp(32) : see reference to function template instantiation 'void boost::_bi::list2<A1,A2>::operator ()<F,boost::_bi::list1<A &>>(boost::_bi::type<T>,F &,A &,int)' being compiled 1> with 1> [ 1> A1=boost::reference_wrapper<delegate>, 1> A2=boost::arg<1>, 1> F=boost::_mfi::mf1<void,A,delegate &>, 1> T=void, 1> A=boost::_bi::list1<A &> 1> ] 1> e:\program files\microsoft visual studio 9.0\vc\include\algorithm(29) : see reference to function template instantiation 'void boost::_bi::bind_t<R,F,L>::operator ()<T>(A1 &)' being compiled 1> with 1> [ 1> R=void, 1> F=boost::_mfi::mf1<void,A,delegate &>, 1> L=boost::_bi::list2<boost::reference_wrapper<delegate>,boost::arg<1>>, 1> T=A, 1> A1=A 1> ] 1> c:\test\t458\t458\t458.cpp(39) : see reference to function template instantiation '_Fn1 std::for_each<boost::void_ptr_iterator<VoidIter,T>,boost::_bi::bind_t<R,F,L>>(_ InIt,_InIt,_Fn1)' being compiled 1> with 1> [ 1> _Fn1=boost::_bi::bind_t<void,boost::_mfi::mf1<void,A,delegate &>,boost::_bi::list2<boost::reference_wrapper<delegate>,boost::arg<1>>>, 1> VoidIter=std::_Vector_iterator<void *,std::allocator<void *>>, 1> T=A, 1> R=void, 1> F=boost::_mfi::mf1<void,A,delegate &>, 1> L=boost::_bi::list2<boost::reference_wrapper<delegate>,boost::arg<1>>, 1> _InIt=boost::void_ptr_iterator<std::_Vector_iterator<void *,std::allocator<void *>>,A> 1> ] 1> c:\test\t458\t458\t458.cpp(37) : while compiling class template member function 'void Test<CLIENTS>::run(void)' 1> with 1> [ 1> CLIENTS=Acoll<A> 1> ] 1> c:\test\t458\t458\t458.cpp(47) : see reference to class template instantiation 'Test<CLIENTS>' being compiled 1> with 1> [ 1> CLIENTS=Acoll<A> 1> ]

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Boost MPI and threads
by Clément Rezvoy 27 Jan '09

27 Jan '09

Hi all, I have a question regarding boost MPI and thread support. boost::mpi::environment uses MPI::Init to initialize MPI. I would like to be able to assess the supported thread level using MPI::Init_thread. Is it possible to first initialize MPI via MPI::Init_thread and then create a boost::mpi::environment ? the documentation reads: If the MPI environment has not already been initialized, initializes MPI with a call to MPI_Init does that also work if the initialisation is not carried out via boost::mpi::environment? Assuming the underlying MPI implementation supports it, is it safe to mix boost threads with boost MPI, at least at a FUNNELED level, carrying out all the MPI communications in the main thread? thanks for your help, Clément Rezvoy.

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Build Boost 1.37 under Solaris 10 - what is the best way
by Georg Sauthoff 27 Jan '09

27 Jan '09

Hi, I built boost under Solaris with the Sun C++ compiler 12. To summarize the experience: informations are very much scattered around in the boost documentation/web pages and you have to learn bjam Finally I did it like this: $ ./configure --prefix=/my/prefix \ --with-libraries=test,program_options --with-toolset=sun $ cat > user-config.jam using sun : 5.9 : CC : <cxxflags>"-library=stlport4 -features=tmplife -features=tmplrefstatic -O" <linkflags>-library=stlport4 ; ^D $ ./tools/jam/src/bin.solaris/bjam -sICU_PATH=/usr \ --user-config=user-config.jam --with-test --with-program_options \ address-model=64 -d3 $ ./tools/jam/src/bin.solaris/bjam -sICU_PATH=/usr \ --user-config=user-config.jam --with-test --with-program_options \ address-model=64 \ -d3 --prefix=/my/prefix install My software works so far with this compiled version of boost under Solaris 10. Well, is this the right/best/official/boost/bjam-way to build boost on Solaris 10? The default sun toolset-settings does not seem to include even '-library=stlport4' option, although the Sun CC is infamous for its nonconforming STL implementation which is selected by default. Is it possible to improve the sun bjam toolset in such a way, that it selects -features=tmplife by default, if it detects that CC is of version 5.9? And is it possible to select the addresss-model=64 property via the ./configure command line? Is there is a './configure --help' aequivalent for bjam to display the options of the current toolset without reading the bjam toolset source? Best regards Georg Sauthoff

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boost::signals - can't generate assignment op.
by Noah Roberts 27 Jan '09

27 Jan '09

I know that signals can't be assigned or copied, and as far as I can tell I have made sure that never happens. However, I'm still getting the warning. We have no warning policy here. Code followed by compiler output, what do I need to do?: ------------------------------------------- #include <boost/signal.hpp> #include <boost/function.hpp> struct rect {}; struct document { document() : changed_sig() {} virtual rect extents() const = 0; virtual ~document() {} boost::signals::connection attach(boost::function<void (document&)> const& slot) { return changed_sig.connect(slot); } private: boost::signal<void (document&)> changed_sig; document(document const&) {} document& operator=(document const&) { return *this;} protected: void changed(document & d) { changed_sig(d); } }; int main() { } ------------------------------------------------ 1>e:\boostvs2\include\boost\signals\trackable.hpp(163) : warning C4512: 'boost::signals::detail::bound_objects_visitor' : assignment operator could not be generated 1> e:\boostvs2\include\boost\signals\trackable.hpp(66) : see declaration of 'boost::signals::detail::bound_objects_visitor' 1>e:\boostvs2\include\boost\signals\signal_template.hpp(71) : warning C4512: 'boost::signals::detail::args1<T1>' : assignment operator could not be generated 1> with 1> [ 1> T1=document & 1> ] 1> e:\boostvs2\include\boost\signals\signal_template.hpp(344) : see reference to class template instantiation 'boost::signals::detail::args1<T1>' being compiled 1> with 1> [ 1> T1=document & 1> ] 1> e:\boostvs2\include\boost\signals\signal_template.hpp(335) : while compiling class template member function 'void boost::signal1<R,T1,Combiner,Group,GroupCompare,SlotFunction>::operator ()(T1)' 1> with 1> [ 1> R=void, 1> T1=document &, 1> Combiner=boost::last_value<void>, 1> Group=int, 1> GroupCompare=std::less<int>, 1> SlotFunction=boost::function<void (document &)> 1> ] 1> e:\boostvs2\include\boost\signal.hpp(335) : see reference to class template instantiation 'boost::signal1<R,T1,Combiner,Group,GroupCompare,SlotFunction>' being compiled 1> with 1> [ 1> R=void, 1> T1=document &, 1> Combiner=boost::last_value<void>, 1> Group=int, 1> GroupCompare=std::less<int>, 1> SlotFunction=boost::function<void (document &)> 1> ] 1> e:\dev_workspace\experimental\scratch\scratch\main.cpp(19) : see reference to class template instantiation 'boost::signal<Signature>' being compiled 1> with 1> [ 1> Signature=void (document &) 1> ] 1>Linking...

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