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[numeric_cast] unwished warnings
by Ovanes Markarian 22 Apr '07

22 Apr '07

Hello! Using numeric_cast I face a warning in MSVC 8.0 Express Edition e:\libraries\boost\include\boost-1_35\boost\numeric\conversion\cast.hpp(41) : warning C4267: 'return' : conversion from 'size_t' to 'Uint32', possible loss of data e:\projects\fundamental_type_factory.cpp(62) : see reference to function template instantiation 'Target boost::numeric_cast<T,msgcat::fundamental_type::numeric_result>(Source)' being compiled with [ Target=Uint32, T=Uint32, Source=fundamental_type::numeric_result ] e:\projects\fundamental_type_factory.cpp(61) : while compiling class template member function 'fundamental_type &`anonymous-namespace'::fundamental_type_impl<T>::operator =(const fundamental_type::numeric_result &)' .... Trying to compile without warnings I am wondering about this warning, since I use the cast to raise an exception at runtime if data are lost. Is it logical? With Kind Regards, Ovanes

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[filesystem] About use on Windows
by Kirit Sælensminde 22 Apr '07

22 Apr '07

Hi everyone, We've been using Boost since around '98 and have had a great deal of mileage out of the smart pointer libraries (thanks!) and are now starting to try out some of the other libraries. We ran into two problems with the filesystem library, the first we're starting with. 1) The initial problem was that we had always been compiling with the __fastcall convention, but the Boost libraries are built using __cdecl. In the end we switched to __cdecl, but should there not be a #define with the build declaration in the headers? 2) The path class only uses narrow strings. For use with the standard C++ libraries this seems fine, but I think once the new standard goes through there should be wide character variants for the file library. In any case we often use bits of the Win32 API which do take wide characters. I'm just wondering if we should just copy the path class to make a wpath class path and if we do so should we give that copy back to integrate with the normal Boost library? This second is probably of more relevance to us now that we've changed our build options. Kirit

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[Boost.DateTime] Error in documentation?
by johneddy101＠comcast.net 21 Apr '07

21 Apr '07

The description of the time_duration::ticks_per_second method reads: "Return the number of ticks in a second. For example, if the duration supports nanoseconds then the returned result will be 1000000." Shouldn't it be 1000000000 or change nano to micro? Found at: http://www.boost.org/doc/html/date_time/posix_time.html#date_time.posix_tim… and in cvs at: http://boost.cvs.sourceforge.net/boost/boost/libs/date_time/xmldoc/time_dur… Thanks

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Re: [Boost-users] Boost Regex in a DLL
by Metasebia Moges 21 Apr '07

21 Apr '07

>That sounds like a possible runtime-library problem. Can you switch both >your application and the dll to use the dynamic C++ runtime? Yes, thanks. The problem is fixed! Best regards, mmoges _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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boost::iostreams de/compress data from memory question.
by CPPer 21 Apr '07

21 Apr '07

Hi! Is there anyone know how to use boost::iostreams to de/compress data from memory ? >From file the code bellow works well: #include <fstream> #include <iostream> #include <boost/iostreams/filtering_streambuf.hpp> #include <boost/iostreams/copy.hpp> #include <boost/iostreams/filter/gzip.hpp> namespace io = boost::iostreams; int main() { using namespace std; ifstream file("hello.gz", ios_base::in | ios_base::binary); io::filtering_streambuf<io::input> in; in.push(io::gzip_decompressor()); in.push(file); io::copy(in, cout); } But if I changed ifstream into istringstream like this: #include <fstream> #include <sstream> #include <boost/iostreams/filtering_stream.hpp> //#include <boost/iostreams/copy.hpp> #include <boost/iostreams/filter/gzip.hpp> namespace io = boost::iostreams; int main() { using namespace std; ifstream file("hello.gz", ios_base::in | ios_base::binary); io::filtering_istream in; in.push(io::gzip_decompressor()); in.push(file); //std::ostringstream ostr; //io::copy (in, ostr); //std::string stir = ostr.str (); std::string stir; in >> stir; //ofstream ofs("output.gz", ios_base::out | ios_base::binary); ostringstream ostr; io::filtering_ostream out; out.push (io::gzip_compressor()); out.push (ostr); out << stir; stir= out.str(); } the std::string stir always NULL when I want to get the data after compress. Sorry for my bad English.. I am a Chinese.

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Re: [Boost-users] Boost Regex in a DLL
by Metasebia Moges 21 Apr '07

21 Apr '07

Dear Bronek Kozicki, >because it really is bad idea. I will explain why: C++ runtime needs >access to the heap in order to be able to create objects (like strings). >On Windows each process owns multiple heaps and the runtime holds handle >to one. If you use static runtime, this handle is linked into executable >(it's a static variable). On Windows you have two kinds of executables: >DLL and EXE. Each copy of static C++ runtime that is statically linked >into an executable will have own heap handle, thus heaps (of EXE and all >DLLs linked with static runtime, running inside the process) will be >separate. Now imagine what happens if function inside a DLL creates a >string (be it 'std::string("foo bar")' or simply 'new char[20]') and >returns it to EXE that called it - string would be created in the >context of C++ runtime statically linked with the DLL (one heap) and >then passed (and some time later destroyed) in the context of another >C++ runtime, the one statically linked into the EXE (other heap). The >trouble is that you cannot allocate memory on one heap and then free it >on another, because they know nothing of one another - the attempt will >likely simply corrupt the heap of the other runtime (thus crashing your >process some time later). This is why whenever you want to use DLL and >EXE and pass C++ objects of or pointers between them, it is crucial that >they all (DLLs and EXE) use one copy of the C++ runtime - that is >dynamically linked one (option /MD for release build and /MDd for debug). What a nice lecture! Thank you very much. That helped me fix the problem. One additional thing worth mentioning is that I had to copy the boost_regex_vc71_mt_gd_1_33_1.dll into my the directory where I placed all my executables (dlls and exe). I wonder if that was mentioned somewhere in the documentation! Moreover, eventhough the boost.regex code is only in one of the dlls (isolated), I had to include the macro BOOST_REGEX_DYN_LINK (but, Dr. Maddock once informed me that this is not necessary). Just wondering. Thank you again! Best regards, mmoges _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Re: [Boost-users] Boost Regex in a DLL
by Metasebia Moges 21 Apr '07

21 Apr '07

Dear Dr. John Maddock, >You can use Boost.Regex in a dll by defining BOOST_REGEX_DYN_LINK when >building your dll, but as long as the regex code is isolated to your dll and >doesn't spill over into it's public interface then this shouldn't be >necessary. Like I said in an earlier e-mail, the code is isolated. However, to make things sure I added it as: #define BOOST_REGEX_DYN_LINK in the source code and there is no change. Then I defined it in Properties->Preprocessor Definitions. Then it complains as: "Mixing a Boost dll with a static runtime is a really bad idea ...". I don't know why? >Other than that it's hard to say what the issue might be without >seeing your code. The surprising thing is that a single line of BOOST code (just an expression) disturbs the program. For example, I added: boost::regex sre("!NULL|sil|SIL"); only and didn't do anything with it. Then when I run the program with the perfectly working code (non-boost), it misbehaves. So I don't think it is a problem with my regex code as all. I don't think this problem is asscociated with the main program using my dll too. Otherwise, I must have missed something essential. I want to use Boost but I really need help at this point. Thank you in advance! mmoges _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Problems with serializing
by Hansi Hansi 21 Apr '07

21 Apr '07

I don't know if this is the right forum for that... In the following example I get the compile error (VS2005) Error 1 error C2027: use of undefined type 'boost::STATIC_ASSERTION_FAILURE<x>' c:\boost_1_33_1\boost\archive\detail\oserializer.hpp 567 Can anyone say me why? If I define const gps_position it works, otherwhise it fails class gps_position { private: friend class boost::serialization::access; // When the class Archive corresponds to an output archive, the // & operator is defined similar to <<. Likewise, when the class Archive // is a type of input archive the & operator is defined similar to >>. template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & degrees; ar & minutes; ar & seconds; } int degrees; int minutes; float seconds; public: gps_position(){}; gps_position(int d, int m, float s) : degrees(d), minutes(m), seconds(s) {} }; int _tmain(int argc, _TCHAR* argv[]) { gps_position newVector; const gps_position* poldVector = new gps_position(); { std::ofstream ofs("test.dat"); boost::archive::text_oarchive oa(ofs); oa << poldVector; } { std::ifstream ifs("test.dat", std::ios_base::binary); boost::archive::text_iarchive ia(ifs); ia >> newVector; // read data } return 0; } _______________________________________________________________ SMS schreiben mit WEB.DE FreeMail - einfach, schnell und kostenguenstig. Jetzt gleich testen! http://f.web.de/?mc=021192

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Timer suspended during disk operations?
by Przemyslaw Tumidajewicz 20 Apr '07

20 Apr '07

Hello everyone, I've been trying to use the boost/timer class to provide some information on the time taken by subtasks in my program. I have noticed that times seem to be reported fine as long as subtasks are doing CPU processing, but disk operations seem to suspend the timer. For instance buffering a bigger file to memory is reported to take eg. half a second, while it can clearly be seen that the program is running for 15 seconds. Any ideas on what can cause this behaviour and if there is any way to make it work properly? I am using g++ 3.4.4 with boost 1.33.1 under Win XP Pro SP2. Thanks in advance! --Przem

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[Serialization/Archive] Handle comments in xml-files
by Gerrit Brehmer 20 Apr '07

20 Apr '07

Hi, can anyone tell me where in the code I can find the place, where I can disable comment-processing as normal name-value-pairs? Because If I have xml-comments () in the xml-file, the deserialization will fail with a boost::archive::archive_exception. Thanks in advance for your help! Gerrit

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