March 2011 - Boost-users - lists.preview.boost.org

Re: [Boost-users] using boost.asio with wx widgets
by Marat Abrarov 21 Mar '11

21 Mar '11

Hi, Sean Farrow. I use Boost.Asio with Qt. I don't use the default MSVS C++ project structure with additional header, where MSVS adds some preprocessor directives by default. So I moved those directives (preprocessor defines) to project settings: WIN32 WIN32_LEAN_AND_MEAN WINVER=0x0500 _WIN32_WINNT=0x0500 _WIN32_WINDOWS=0x0410 _WIN32_IE=0x0600 May be would solve your problem? Regards, Marat Abrarov.

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Thread Interruption Best Practice
by Dom Driver 21 Mar '11

21 Mar '11

Hi List, I'm fairly new to boost, and have recently started to use the threading system from v1.46 in an app I'm writing targeting Linux. This was primarily to enable execution of threads to be blocked until a condition variable is set, at which point the thread is kicked awake and actions whatever is waiting to be done. All good, and all working as expected. However, I've got another thread which sits listening for data on a socket using a Linux select() call. This blocks until data is available for reading, at which point it is read from the socket as expected. This also works fine, except on termination of the application. Using native Linux implementations, a signal can be sent to the thread that is blocking on the select() call, at which point the call returns, and the EINTR error is set. I can therefore check for this condition and handle appropriately. Is there a way to send a Linux signal (or boost equivalent) to a specific boost thread to emulate this behaviour? Failing that, is there an alternative implementation of the classic Linux select()/read() functionality using boost classes? I had a look at the async I/O library and it seems a bit convoluted. TIA, Dom

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Re: [Boost-users] [boost::thread] interrupt a future get boost::unknown_exception
by 乔志强 21 Mar '11

21 Mar '11

It may be a bug of the thread or future. in boost_1_46_0/doc/html/thread/synchronization.html these Member functions: shared_future class template: Member function get() Member function wait() Member function timed_wait() and unique_future class template: Member function get() Member function wait() Member function timed_wait() Throws: ........ boost::thread_interrupted if the result associated with *this is not ready at the point of the call, and the [current] thread is interrupted. ............ the [current] thread is interrupted. Should be the [working] thread is interrupted ? > > [Windows XP, VC++ 10, boost 1.46] > > When interrupt a future, the future.get() throw boost::unknown_exception, > > Not boost::thread_interrupted. > > > > Class boost::thread_interrupted should have a base class for > > current_exception_impl() to catch it ? or use BOOST_THROW_EXCEPTION to throw ? ////////// namespace boost { class thread_interrupted {}; } These function use [ throw thread_interrupted(); ] : this_thread ::interruption_point() // pthread / win32 this_thread::interruptible_wait() // win32 interruption_checker:: check_for_interruption()// pthread ///////////// // [Windows XP, VC++ 10, boost 1.46] #include <boost/thread.hpp> #include <boost/date_time/posix_time/posix_time_types.hpp> #include <boost/thread/future.hpp> using namespace boost::posix_time; using namespace boost; int foo() { this_thread::sleep(seconds(1000)); return 0; } int main(int argc, char** argv) { boost::packaged_task<int> pt(&foo); boost::unique_future<int> fi = pt.get_future(); boost::thread task(std::move(pt)); // launch task on a thread task.interrupt(); try { int v = fi.get(); } catch (boost::exception& exc) { std::cerr << "ERROR: " << boost::diagnostic_information(exc) << std::endl; } } > > > > // unknown_exception////////////////// > > ERROR: Throw in function (unknown) > > Dynamic exception type: class boost::exception_detail::clone_impl<class > > boost::unknown_exception> > > std::exception::what: Unknown exception

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[function] Compiler error with Boost 1.46.1
by Boris Schaeling 20 Mar '11

20 Mar '11

The sample program at http://en.highscore.de/cpp/boost/src/3.4.3/main.cpp can't be compiled anymore with Boost 1.46.1 (using VC++ 2010). Is this a known problem? 1>------ Rebuild All started: Project: Test, Configuration: Debug Win32 ------ 1> main.cpp 1>c:\boost\include\boost-1_46_1\boost\function\function_template.hpp(539): error C2668: 'boost::mem_fn' : ambiguous call to overloaded function 1> c:\boost\include\boost-1_46_1\boost\bind\mem_fn_cc.hpp(25): could be 'boost::_mfi::mf1<R,T,A1> boost::mem_fn<void,world,std::ostream&>(R (__thiscall world::* )(A1))' 1> with 1> [ 1> R=void, 1> T=world, 1> A1=std::ostream & 1> ] 1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\xxmem_fn(32): or 'std::tr1::_Mem_fn2<_Rx,_Pmf,_Arg0,_Arg1> std::tr1::mem_fn<void,world,std::ostream&>(_Rx (__thiscall world::* )(_Arg1))' [found using argument-dependent lookup] 1> with 1> [ 1> _Rx=void, 1> _Pmf=void (__thiscall world::* )(std::ostream &), 1> _Arg0=world, 1> _Arg1=std::ostream & 1> ] 1> while trying to match the argument list '(void (__thiscall world::* )(std::ostream &))' 1> c:\boost\include\boost-1_46_1\boost\function\function_template.hpp(492) : see reference to function template instantiation 'bool boost::detail::function::basic_vtable2<R,T0,T1>::assign_to<F>(MemberPtr,boost::detail::function::function_buffer &,boost::detail::function::member_ptr_tag)' being compiled 1> with 1> [ 1> R=void, 1> T0=world *, 1> T1=std::basic_ostream<char,std::char_traits<char>> &, 1> F=void (__thiscall world::* )(std::ostream &), 1> MemberPtr=void (__thiscall world::* )(std::ostream &) 1> ] 1> c:\boost\include\boost-1_46_1\boost\function\function_template.hpp(915) : see reference to function template instantiation 'bool boost::detail::function::basic_vtable2<R,T0,T1>::assign_to<Functor>(F,boost::detail::function::function_buffer &)' being compiled 1> with 1> [ 1> R=void, 1> T0=world *, 1> T1=std::basic_ostream<char,std::char_traits<char>> &, 1> Functor=void (__thiscall world::* )(std::ostream &), 1> F=void (__thiscall world::* )(std::ostream &) 1> ] 1> c:\boost\include\boost-1_46_1\boost\function\function_template.hpp(722) : see reference to function template instantiation 'void boost::function2<R,T0,T1>::assign_to<Functor>(Functor)' being compiled 1> with 1> [ 1> R=void, 1> T0=world *, 1> T1=std::basic_ostream<char,std::char_traits<char>> &, 1> Functor=void (__thiscall world::* )(std::ostream &) 1> ] 1> c:\boost\include\boost-1_46_1\boost\function\function_template.hpp(1065) : see reference to function template instantiation 'boost::function2<R,T0,T1>::function2<void(__thiscall world::* )(std::ostream &)>(Functor,int)' being compiled 1> with 1> [ 1> R=void, 1> T0=world *, 1> T1=std::basic_ostream<char,std::char_traits<char>> &, 1> Functor=void (__thiscall world::* )(std::ostream &) 1> ] 1> c:\users\boris\documents\visual studio 2010\projects\test\main.cpp(14) : see reference to function template instantiation 'boost::function<Signature>::function<void(__thiscall world::* )(std::ostream &)>(Functor,int)' being compiled 1> with 1> [ 1> Signature=void (world *,std::ostream &), 1> Functor=void (__thiscall world::* )(std::ostream &) 1> ] 1>c:\boost\include\boost-1_46_1\boost\function\function_template.hpp(539): error C2780: 'bool boost::detail::function::basic_vtable2<R,T0,T1>::assign_to(const boost::reference_wrapper<FunctionObj> &,boost::detail::function::function_buffer &,boost::detail::function::function_obj_ref_tag)' : expects 3 arguments - 2 provided 1> with 1> [ 1> R=void, 1> T0=world *, 1> T1=std::basic_ostream<char,std::char_traits<char>> & 1> ] 1> c:\boost\include\boost-1_46_1\boost\function\function_template.hpp(625) : see declaration of 'boost::detail::function::basic_vtable2<R,T0,T1>::assign_to' 1> with 1> [ 1> R=void, 1> T0=world *, 1> T1=std::basic_ostream<char,std::char_traits<char>> & 1> ] 1>c:\boost\include\boost-1_46_1\boost\function\function_template.hpp(539): error C2780: 'bool boost::detail::function::basic_vtable2<R,T0,T1>::assign_to(FunctionObj,boost::detail::function::function_buffer &,boost::detail::function::function_obj_tag)' : expects 3 arguments - 2 provided 1> with 1> [ 1> R=void, 1> T0=world *, 1> T1=std::basic_ostream<char,std::char_traits<char>> & 1> ] 1> c:\boost\include\boost-1_46_1\boost\function\function_template.hpp(599) : see declaration of 'boost::detail::function::basic_vtable2<R,T0,T1>::assign_to' 1> with 1> [ 1> R=void, 1> T0=world *, 1> T1=std::basic_ostream<char,std::char_traits<char>> & 1> ] 1>c:\boost\include\boost-1_46_1\boost\function\function_template.hpp(539): error C2780: 'bool boost::detail::function::basic_vtable2<R,T0,T1>::assign_to(MemberPtr,boost::detail::function::function_buffer &,boost::detail::function::member_ptr_tag)' : expects 3 arguments - 2 provided 1> with 1> [ 1> R=void, 1> T0=world *, 1> T1=std::basic_ostream<char,std::char_traits<char>> & 1> ] 1> c:\boost\include\boost-1_46_1\boost\function\function_template.hpp(533) : see declaration of 'boost::detail::function::basic_vtable2<R,T0,T1>::assign_to' 1> with 1> [ 1> R=void, 1> T0=world *, 1> T1=std::basic_ostream<char,std::char_traits<char>> & 1> ] 1>c:\boost\include\boost-1_46_1\boost\function\function_template.hpp(539): error C2780: 'bool boost::detail::function::basic_vtable2<R,T0,T1>::assign_to(FunctionPtr,boost::detail::function::function_buffer &,boost::detail::function::function_ptr_tag)' : expects 3 arguments - 2 provided 1> with 1> [ 1> R=void, 1> T0=world *, 1> T1=std::basic_ostream<char,std::char_traits<char>> & 1> ] 1> c:\boost\include\boost-1_46_1\boost\function\function_template.hpp(511) : see declaration of 'boost::detail::function::basic_vtable2<R,T0,T1>::assign_to' 1> with 1> [ 1> R=void, 1> T0=world *, 1> T1=std::basic_ostream<char,std::char_traits<char>> & 1> ] ========== Rebuild All: 0 succeeded, 1 failed, 0 skipped ========== Boris

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plus<boost::gregorian::date> - how to?
by qplace 20 Mar '11

20 Mar '11

I need to be able to either add or substruct boost::gregorian::days from boost::gregorian::date. As far as I understand I have to define plus<boost::gregorian::date> and minius<boost::gregorian::date> and provide function operators for them. My question is: Function operator required in plus and minus template has a form of T operator()(const T& x, const T& y) , but I need to use not only gregorian::date, but gregorian::days as well. Any advise is greatly appreciated.

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storing a boost::asio::io_service in a boost.tuple
by Sean Farrow 20 Mar '11

20 Mar '11

Hi: I need to store a boost::asio::io_service in a boost::tuple. Each boost::tuple needs an individual io_service. Given that io_service is noncopyable, and I'm working in a constructor what is the best way of doing this? Cheers Sean.

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[spirit][karma][range] Range adaptors not handled by karma?
by Ravi 20 Mar '11

20 Mar '11

Hi, Does spirit karma handle boost.range adaptors correctly? The following code compiles but fails at run-time as the end of the range is not seen by karma: --8<----8<----8<----8<----8<----8<----8<----8<----8<----8<----8<----8<-- #include <boost/range/adaptors.hpp> #include <boost/assign.hpp> #include <iostream> #include <vector> #include <boost/spirit/include/karma.hpp> int main(int argc, const char* argv[]) { using namespace boost::adaptors; using namespace boost::assign; std::vector<int> input; input += 1,2,3,4,5,6,7,8,9,10; std::ostream_iterator<char> os( std::cout ); using boost::spirit::karma::int_; using boost::spirit::karma::generate_delimited; using boost::spirit::ascii::space; //generate_delimited( os, int_ % ',', space, // input | strided(2) ); // <- works generate_delimited( os, int_ % ',', space, input | copied(1,6) | strided(2) ); std::cout << std::endl; return 0; } --8<----8<----8<----8<----8<----8<----8<----8<----8<----8<----8<----8<-- The tests were done with boost 1.45. Regards, Ravi

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using boost.asio with wx widgets
by Sean Farrow 20 Mar '11

20 Mar '11

Hi: I'm trying to use wx widgets with boost.asio. I'm including wx.h in the main header file-which is not being included in the header I'm concerned with now. Wx.h includes windows.h and therefore winsock.h. I'm getting the error 1189 #error : winsock.h has already been included. I've defined win32_lean_and_mean before including boost/asio.hpp. I've also tried including wx.h before asio.hpp in the header I'm dealing with now, this makes no difference I still get the same error. Has anyone got any other ideas? Any help appreciated. Regards Sean.

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traversing archive file (tar, zip) directories the boost way?
by Ákos Maróy 20 Mar '11

20 Mar '11

Hi, I wonder if there is a boost-friendly API to manage directory structures in archive file formats, like tar, zip & the like? In boost iostreams, there are filters for popular compression formats, like gzip, bzip2 and zip. but these only provide stream compression / decompression - and rightfully so. In boost filesystem, one has a portable API for traversing file system directory structures, which is very nice. But I'm not aware of a boost-friendly API that would allow traversing in & managing directory structure & multiple files in archive formats, such as tar & zip. of course there are C libraries, such as libtar or zlib, or ziplib, but these are all C libraries. What I would be looking for is a way to list files & directories in an archive, extract specific files from an archive, and put files into an archive, in a nice, boost-like C++ way. Is there something like this available? Akos

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About includes in numeric/ublas ....matrix.hpp and vector.hpp
by Bhushan Inamdar 20 Mar '11

20 Mar '11

Dear all, I believe, I have set the environment right for the boost libraries. I had done a program a while ago using shared pointers. And after mentioning the includes in the additional includes directories, it compiled. However, no matter what I am trying to do here, the compiler does not find matrix.hpp and vector.hpp in the attached project. I am using Boost version 1.44.0. I have checked the paths and the files do exist there. But, I do not know why my compiler keeps complaining about them being not found. The errors I am getting are as under: Error 1 fatal error C1083: Cannot open include file: 'boost/numeric/ublas/matrix.hpp': No such file or directory c:\users\user\documents\visual studio 2008\projects\dbscanalgo\dbscanalgo\clusters.h 5 DBScanAlgo Error 2 fatal error C1083: Cannot open include file: 'boost/numeric/ublas/matrix.hpp': No such file or directory c:\users\user\documents\visual studio 2008\projects\dbscanalgo\dbscanalgo\dbscan.h 5 DBScanAlgo Error 3 fatal error C1083: Cannot open include file: 'boost/numeric/ublas/matrix.hpp': No such file or directory c:\users\user\documents\visual studio 2008\projects\dbscanalgo\dbscanalgo\dbscan.h 5 DBScanAlgo Now, I have configured my paths as under: $(BOOST_ROOT) is ,....C:\Program Files\boost\boost_1_44_0 Then in VS 2008 IDE on main menu, Tools | Options | Projects and Solutions | VC++ directories... I have added... For Include Files : $(BOOST_ROOT)Boost For library files : $(BOOST_ROOT)stage\lib; $(BOOST_ROOT)\libs; $(BOOST_ROOT)bin.V2 Also, after having done this, I go to the project properties, I go to C/C++ Node and on the RHS pane in the "Additional Include Directories" option add the path to "C:\Program Files\boost\boost_1_44_0\boost\numeric\ublas". Even then, I am not able to get it working. Just for your information, I am running VS 2008 professional edition on Windows 7 OS. Please let me know if there is anything wrong here. Thanks, Bhushan

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function<double(double)> - cmath
by er 19 Mar '11

19 Mar '11

Simply bringing this to the attention of the function maintainer, in case it hasn't been mentioned before, and it has any relevance (I can live with it). #include <cmath> #include <boost/function.hpp> typedef function<double(double)> f_; // error C2440 with MSVC 2010. No such problems with GCC 4.2 f_ f = log10; typedef double(*fp)(double); f_ f = fp( log10 ); // clumsy, but solves it

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[context review] Review starts next Monday, Mars 21st
by Vicente BOTET 19 Mar '11

19 Mar '11

Hi all, The review of Oliver Kowalke Context library starts next Monday Mars 21st 2011, and will end on Mars 30th. Boost.Context is a basic building block library that is used for more higher abstractions. It is used by Boost.Fiber, Boost.Tasklet and Boost.Task from the same author. I really hope to see your vote and your participation in the discussions on the Boost DEVELOPMENT mailing lists! Please use [context review] as prefix of your post to make easier the review follow up. You can already download a frozen version for the review from the Vault, TinyURL: http://tinyurl.com/5r77rel or --------------------------------------------------- About the library: Boost.Context provides a possibility to switch between different user-level context and is intended to be the basis for a higher abstraction like coroutine and fiber. A user-level context represents the current execution state, including all registers and CPU flags, the instruction pointer, the stack pointer. boost::context encapsulates such a user-level context and is able to store/restore its associated user-level context. This allows multiple execution paths running on a single thread using a sort of cooperative scheduling (in contrast a thread is preemptively scheduled) - the running boost::context decides explicitly when its yields to allow another boost::context to run (user-level context switching). A context can only run on a single thread at any point in time but may be migrated between thread. A context switch between threads costs usually thousands of CPU cycles on x86 compared to a user-level context switch with few hundreds of cycles. Boost.Context differes to setjmp()/longjmp() in the fact that the C99 standard does not require that longjmp() preserves the current stack frame, e. g. jumping into a function which was exited via a call to longjmp() is undefined. Boost.Context allows to select the mechanism provided by the operating system (ucontext on UNIX, Windows Fibers on Windows) or a faster implementation provided by this library (fcontext using assembler). --------------------------------------------------- Please always state in your review, whether you think the library should be accepted as a Boost library! Additionally please consider giving feedback on the following general topics: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? - Did you try to use the library? With what compiler? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? - Are you knowledgeable about the problem domain? Regards Vicente Review Manager

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[BGL] Separating twin vertices
by Shaun Jackman 19 Mar '11

19 Mar '11

Hi, I have a directed graph where every vertex has a twin vertex. It is known ahead of time which pairs of vertices are twins. I want to remove as few vertices as possible from the graph such that no vertex and its twin is in the same connected component. Could someone suggest an appropriate algorithm? I've just started delving into the BGL. So far I'm suitably impressed! Cheers, Shaun

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boost::exception_detail::error_info_base does not have virtual destructor
by Jens Auer 19 Mar '11

19 Mar '11

Hi, I am compiling a project with a more strict warning set and got the following reports: Error 29 error C4265: 'boost::exception_detail::error_info_base' : class has virtual functions, but destructor is not virtual c:\work\svn\sandbox\externals\boost\include\boost-1_45\boost\exception\detail\error_info_impl.hpp 36 Error 30 error C4265: 'boost::error_info<Tag,T>' : class has virtual functions, but destructor is not virtual c:\work\svn\sandbox\externals\boost\include\boost-1_45\boost\exception\detail\error_info_impl.hpp 69 IMHO these classes should have a virtual destructor as they are intended to be used as base classes. Best wishes, Jens

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[boost::thread] interrupt a future get boost::unknown_exception
by 乔志强 18 Mar '11

18 Mar '11

[Windows XP, VC++ 10, boost 1.46] When interrupt a future, the future.get() throw boost::unknown_exception, Not boost::thread_interrupted. Class boost::thread_interrupted should have a base class for current_exception_impl() to catch it ? or use BOOST_THROW_EXCEPTION in interruptible_wait) ? /////////////// namespace boost { class thread_interrupted {}; } exception_ptr current_exception_impl() { try { throw; } catch( exception_detail::clone_base & e ) { return exception_ptr(e.clone()); } ................ catch( std::exception & e ) { return exception_detail::current_exception_unknown_std_exception(e); } catch( boost::exception & e ) { return exception_detail::current_exception_unknown_boost_exception(e); } catch( ... ) { return exception_detail::current_exception_unknown_exception(); } // unknown_exception////////////////// ERROR: Throw in function (unknown) Dynamic exception type: class boost::exception_detail::clone_impl<class boost::unknown_exception> std::exception::what: Unknown exception //code ///////////////////// #include <boost/thread.hpp> #include <boost/date_time/posix_time/posix_time_types.hpp> #include <boost/thread/future.hpp> using namespace boost::posix_time; using namespace boost; int main(int argc, char** argv) { boost::packaged_task<int> pt( [=]()->int { this_thread::sleep(seconds(1000)); return 0; } ); boost::unique_future<int> fi = pt.get_future(); boost::thread task(std::move(pt)); // launch task on a thread task.interrupt(); try { int v = fi.get(); } catch (boost::exception& exc) { std::cerr << "ERROR: " << boost::diagnostic_information(exc) << std::endl; } }

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[Review] Boost.Type Traits Extension by Frederic Bron
by Joel Falcou 18 Mar '11

18 Mar '11

Dear All, This is the first day of the fast track review of Frédéric Bron's extensions to the Type Traits Library.This reviews will last until March 18th, 2011 under my management. All comments and reviews are very welcome. =========== What is it? =========== This extension adds 37 new traits corresponding to the following 37 operators: - binary: ==, !=,<,<=,>,>=, , +, -, *, /, %, +=, -=, *=, /=, %=, , &&, ||, ,&, |, ^,<<,>>,&=, |=, ^=,<<=,>>= - prefix: ++, --, +, -, !, ~, * - postfix: ++, -- Each trait can detect if the operator can be used with particular types and if needed, if the return type is convertible to some type. =================== Getting the library =================== The latest version can be downloaded by different ways: - from the vault with unix line ending: http://www.boostpro.com/vault/index.php?action=downloadfile&filename=type_t… - from the vault with dos line ending: http://www.boostpro.com/vault/index.php?action=downloadfile&filename=type_t… - from the sandbox:http://svn.boost.org/svn/boost/sandbox/type_traits/ The entry point of the documentation is type_traits/libs/type_traits/doc/html/boost_typetraits/category/value_traits/operators.html The library has been tested with: - MSVC 8, 9, 10 on Windows, - g++ 4.4.5 on Linux, - intel 10.0 and 11.1 on Linux. To test the library, the simplest is to untar the headers in your boost include directory. For this, you can download the header part of the extension: - from the vault with unix line ending: http://www.boostpro.com/vault/index.php?action=downloadfile&filename=type_t… - from the vault with dos line ending: http://www.boostpro.com/vault/index.php?action=downloadfile&filename=type_t…

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Specifying a NVP wrapper
by simone pilozzi 18 Mar '11

18 Mar '11

Hi All, I am working with the serialization library and I made an example class like this. class Contact{ public: Contact(){} Contact(string& name, int phonenumber,long contactdate):name_(name), pnumber_(phonenumber),contactdate_(contactdate){} const string getName() const{return name_;} const long getPhone() const{return pnumber_;} const long getDate() const{return contactdate_;} private: string name_; long pnumber_,contactdate_; friend class boost::serialization::access; template<typename Archive> void serialize(Archive& ar, const unsigned int version){ ar & boost::serialization::make_nvp("name", name_); ar & boost::serialization::make_nvp("phone", pnumber_); ar & boost::serialization::make_nvp("contactdate", contactdate_); } }; Now I would like to allocate the xml file created with the use of this class in a vector, and this is the function: void getFromFile(std::vector<Contact>& contacts,const char* file){ std::ifstream ifile(file); boost::archive::xml_iarchive ia(ifile); ia >> contacts; ifile.close(); } The compiler complains because it misses a NVP wrapper for the class. I could not find an example for that in boost. Could you help me ? Thanks in advance Simone

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Invitation à se connecter sur LinkedIn
by Germain Barret via LinkedIn 18 Mar '11

18 Mar '11

LinkedIn ------------Germain Barret requested to add you as a connection on LinkedIn: ------------------------------------------ Hermann, J'aimerais vous inviter à rejoindre mon réseau professionnel en ligne, sur le site LinkedIn. Germain Accept invitation from Germain Barret http://www.linkedin.com/e/9m2kgu-glf1cpsf-c/vyhGWmEqB2IKeRN9DMTel5y44rvJcs9… View invitation from Germain Barret http://www.linkedin.com/e/9m2kgu-glf1cpsf-c/vyhGWmEqB2IKeRN9DMTel5y44rvJcs9… ------------------------------------------ DID YOU KNOW you can conduct a more credible and powerful reference check using LinkedIn? Enter the company name and years of employment or the prospective employee to find their colleagues that are also in your network. This provides you with a more balanced set of feedback to evaluate that new hire. http://www.linkedin.com/e/9m2kgu-glf1cpsf-c/rsr/inv-27/ -- (c) 2011, LinkedIn Corporation

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[regexp] Replace a substring with a regexp
by Olivier Tournaire 18 Mar '11

18 Mar '11

Hi all, I am not really familiar with regexp, an I am facing a problem. I have some strings containing unicode sequences (like "\u****"), and I would like to replace them with html sequences (such that "\u****" becomes "&#x****;"). I think I can do that with boost regexp, but I really do not know how. The major problem is that I do not now in advance what are the characters for "****". I however know that they are always 4 and alphanumeric. So, I have to detect them and also append after a ";". Do you have any hint on how to do that? Best regards, Olivier

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Boost conflict with OpenCV, Eigen?
by Prva Ponta 18 Mar '11

18 Mar '11

Hi there, I have a program that uses Filesystem, which compiles and runs without problem, but only if used by itself. If I use Filesystem within a program that also needs OpenCV and Eigen libraries, there seems to be a conflict: ... In file included from C:\boost_1_45_0/boost/filesystem/v3/path_traits.hpp:22:0, from C:\boost_1_45_0/boost/filesystem/v3/path.hpp:25, from C:\boost_1_45_0/boost/filesystem.hpp:32, from ..\src\ComputeNatScaleFunction.cpp:18: C:\boost_1_45_0/boost/type_traits/decay.hpp: In instantiation of 'boost::decay<cv::<anonymous enum> >': C:\cmake_binaries\include/opencv2/core/operations.hpp:766:23: instantiated from here C:\boost_1_45_0/boost/type_traits/decay.hpp:28:66: error: 'cv::' is/uses anonymous type C:\boost_1_45_0/boost/type_traits/decay.hpp:28:66: error: trying to instantiate 'template struct boost::remove_reference' C:\boost_1_45_0/boost/type_traits/decay.hpp:38:17: error: 'cv::' is/uses anonymous type C:\boost_1_45_0/boost/type_traits/decay.hpp:38:17: error: trying to instantiate 'template struct boost::remove_reference' C:\boost_1_45_0/boost/type_traits/decay.hpp: In instantiation of 'boost::decay<cv::<anonymous enum> >': C:\cmake_binaries\include/opencv2/core/operations.hpp:917:21: instantiated from here C:\boost_1_45_0/boost/type_traits/decay.hpp:28:66: error: 'cv::' is/uses anonymous type C:\boost_1_45_0/boost/type_traits/decay.hpp:28:66: error: trying to instantiate 'template struct boost::remove_reference' C:\boost_1_45_0/boost/type_traits/decay.hpp:38:17: error: 'cv::' is/uses anonymous type C:\boost_1_45_0/boost/type_traits/decay.hpp:38:17: error: trying to instantiate 'template struct boost::remove_reference' C:\boost_1_45_0/boost/type_traits/decay.hpp: In instantiation of 'boost::decay<Eigen::<anonymous enum> >': C:\Eigen2/Eigen/src/Core/GenericPacketMath.h:116:18: instantiated from here C:\boost_1_45_0/boost/type_traits/decay.hpp:28:66: error: 'Eigen::' is/uses anonymous type C:\boost_1_45_0/boost/type_traits/decay.hpp:28:66: error: trying to instantiate 'template struct boost::remove_reference' C:\boost_1_45_0/boost/type_traits/decay.hpp:38:17: error: 'Eigen::' is/uses anonymous type C:\boost_1_45_0/boost/type_traits/decay.hpp:38:17: error: trying to instantiate 'template struct boost::remove_reference' etc. Are there known conflicts between Boost (1.45) and OpenCV 2.2/Eigen2/other libraries? I am using Eclipse CDT and MinGW toolchain. After going through problems described in http://boost.2283326.n4.nabble.com/How-to-built-boost-td3053130.html, my Filesystem library is of version 3, whereas other ones are of version 2. Cheers, PP

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[Graph] Switching from depth_first_search to depth_first_visit
by Marcus Riemer 17 Mar '11

17 Mar '11

Hello there! I just stumbled over a little bug that is simply due to the wrong visiting pattern used. From what I understand it should simply print a graph with children being indented. The visitor defined for the task itself is just fine. Problem is that currently a depth first *search* is used, which prints each vertex only once. So from my understanding the only thing I need to do is to replace that search with a visit. Sadly replacing the call to depth_first_visit with a call to depth_first_visit is not as easy as I thought ... For the record: The search call itself looks like this: boost::depth_first_search(mGraph, boost::visitor(printer).root_vertex(start)); Looking at the documentation [0] it seems that there is no version with named parameters for the depth first visit. So I need to pass the graph itself, the starting vertex, the visitor and a color map. And its the color map that troubles me ... I have tried around a little to construct such a thing, but so far without success. My try can be found at [1]. This results in a massive compilation error [2]. I am not really experienced with the extent templates are used in the BGL and have no idea what the compiler tries to tell me. Could anyone give me a hint what I am doing wrong? If more sourcecode is required thats not a problem at all. Simply tell me if anything is missing. Access to the source is also not a problem, compilation is quite easy using cmake. Thanks in advance Marcus Riemer [0] http://www.boost.org/doc/libs/1_44_0/libs/graph/doc/depth_first_visit.html [1] http://pastebin.com/ALvnTdj9 [2] http://pastebin.com/bh6d4NpH

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[BGL] clear_out_edges and MutableIncidenceGraph
by Shaun Jackman 17 Mar '11

17 Mar '11

Hi, adjacency_list implements clear_out_edges, but it's not required by any of the graph concepts: http://www.boost.org/doc/libs/1_46_1/libs/graph/doc/graph_concepts.html Could it be added to MutableIncidenceGraph? Actually, now that I check, I don't see MutableIncidenceGraph on that page either, although it is in graph_concepts.hpp. MutableIncidenceGraph requires remove_edge and remove_out_edge_if. clear_out_edges would fit nicely in here, and clear_in_edges in MutableBidirectionalGraph. Cheers, Shaun

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shared_lock( ) causes Segmentation Fault in CentOS 5.5 x64?
by DesertFish 17 Mar '11

17 Mar '11

Dear Pals, I wrote a server program, and there is a class called "apInfoMutex", which can store client's file descriptor info and what messages they sent; the class code is as below: --- class apInfoTable{ public: apInfoTable(); boost::shared_mutex rwMutex; void addFD(int apfd, char *srvceType, vector<string> *codeList); void delFD(int apfd); bool getFD(list<int> *des, char *srvceType, char *srvceCode); private: boost::unordered_map<int, boost::unordered_set<pair<string, string> > > tableFD; boost::unordered_map<pair<string, string>, boost::unordered_set<int> > tablePush; }; --- there is just one apInfoTable as global declaration in my program, but there would be two or more threads to calling these public method at the same time, and there is a method called "getFD()" in this class, the code is as below: --- bool apInfoTable::getFD(list<int> *des, char *type, char *code){ bool flag=false; boost::shared_lock<boost::shared_mutex> lock(rwMutex); for(boost::unordered_set<int>::iterator it=tablePush[pair<string, string> (type, code)].begin();it!=tablePush[pair<string, string>(type, code)].end ();it++){ flag=true; des->push_back(*it); } return flag; } --- I found if I calling getFD() method like this: char type[12]; char code[32]; list<int> fdList; memset(type, 0x00, sizeof(type)); memset(code, 0x00, sizeof(code)); memcpy(type, "My Type", sizeof("My Type")); memcpy(code, "My Code", sizeof("My Code")); fdList.clear(); bool rc=getFD(&fdList, type, code); I will got "Segmentation Fault" problem, but if I put different parameter like this: bool rc=getFD(&fdList, "My Type", "My Code"); or using boost::mutex instead of shared_lock() and shared_mutex in getFD(), there wouldn't be any problem when running program. is there any problem with my code? or did I use shared_lock() and shared_mutex incorrectly? P.S--I tried using unique_lock or scoped_lock instead of shared_lock(), but there is just no any problem when I using normal boost::mutex sincerely thanks to you Zap

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[Review] Type Traits Extension ending tomorrow
by Joel Falcou 17 Mar '11

17 Mar '11

Dear All, The fast track review of Frédéric Bron's extensions to the Type Traits Library is ending tomorrow. If you plan to submit a review, please do so as soon as possible. Thanks in advance to all participants of the review. =========== What is it? =========== This extension adds 37 new traits corresponding to the following 37 operators: - binary: ==, !=,<,<=,>,>=, , +, -, *, /, %, +=, -=, *=, /=, %=, , &&, ||, ,&, |, ^,<<,>>,&=, |=, ^=,<<=,>>= - prefix: ++, --, +, -, !, ~, * - postfix: ++, -- Each trait can detect if the operator can be used with particular types and if needed, if the return type is convertible to some type. =================== Getting the library =================== The latest version can be downloaded by different ways: - from the vault with unix line ending: http://www.boostpro.com/vault/index.php?action=downloadfile&filename=type_t… - from the vault with dos line ending: http://www.boostpro.com/vault/index.php?action=downloadfile&filename=type_t… - from the sandbox:http://svn.boost.org/svn/boost/sandbox/type_traits/ The entry point of the documentation is type_traits/libs/type_traits/doc/html/boost_typetraits/category/value_traits/operators.html The library has been tested with: - MSVC 8, 9, 10 on Windows, - g++ 4.4.5 on Linux, - intel 10.0 and 11.1 on Linux. To test the library, the simplest is to untar the headers in your boost include directory. For this, you can download the header part of the extension: - from the vault with unix line ending: http://www.boostpro.com/vault/index.php?action=downloadfile&filename=type_t… - from the vault with dos line ending: http://www.boostpro.com/vault/index.php?action=downloadfile&filename=type_t…

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Boost profile for ODB
by Boris Kolpackov 17 Mar '11

17 Mar '11

Hi, I would like to briefly mention that we have released the Boost profile for ODB, an open-source object-relational mapping (ORM) system for C++. The Boost profile provides glue code that seamlessly integrates various Boost components, such as smart pointers, containers, and value types, with ODB. This initial release of the profile covers the most commonly used types from the smart_ptr, unordered, and date_time Boost libraries. For example, now we can easily persist a class like this: #pragma db object class employee { ... boost::gregorian::date born_; boost::unordered_set<std::string> emails_; boost::shared_ptr<employer> employer_; }; For a more detailed discussion of the Boost profile, see the following blog post: http://www.codesynthesis.com/~boris/blog/2011/03/16/odb-1-2-0-released/ Or refer directly to Part III, "Profiles" in the ODB Manual: http://www.codesynthesis.com/products/odb/doc/manual.xhtml#III Boris

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