July 2008 - Boost-users - lists.preview.boost.org

[Conversion] imprecision with lexical_cast from double to std::string
by Andreas Ries 30 Jul '08

30 Jul '08

Hi, I'm using the borland toolset 5.8.2 under Win XP and have a problem doing the following: double val = 795.6352; string result = boost::lexical_cast <string> (val); the resulting string is: "795.63520000000005" with boost 1_35_0 the resulting string is: "795.6352000000001" with boost_1_34_0 Can anybody help?

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dll-interface problems
by Andrej van der Zee 30 Jul '08

30 Jul '08

Hi, I am not much of a Windows programmer, so I have a basic question. I want to make a library that (among other stuff) defines an exception like this: #include <boost/exception/exception.hpp> namespace speedo { typedef boost::error_info<struct tag_error, unsigned> error_info; class __declspec(dllexport) exception : public boost::exception { }; } When I try to compile this, I get the following warning: c:\cygwin\home\andrej\speedo\trunk\util\exception.h(14) : warning C4275: non dll-interface class 'boost::exception' used as base for dll-interface class 'speedo::exception' C:\cygwin\home\Andrej\speedo\trunk\boost/exception/exception.hpp(47) : see declaration of 'boost::exception' c:\cygwin\home\andrej\speedo\trunk\util\exception.h(13) : see declaration of 'speedo::exception' Is this a problem, and, how do I get rid of this without changing the boost-exception lib itself? Cheers, Andrej __________________________________________________________ Not happy with your email address?. Get the one you really want - millions of new email addresses available now at Yahoo! http://uk.docs.yahoo.com/ymail/new.html

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Reading a file with filesystem
by Simon Pickles 30 Jul '08

30 Jul '08

Hi Say I want to copy the contents of a file into memory, how do I do the actual copy. Eg boost::filesystem::path p = "file.txt" const unsigned int filesize = boost::filesystem::file_size( p ); unsigned char* buffer = new unsigned char[filesize]; // how do I copy file contents into buffer? Many thanks Simon

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boost::date_time
by Husain Das 30 Jul '08

30 Jul '08

I am using Visual C++ 9.0 2008 Express Edition with the pre-built boost libraries ver 1.35.0 for Windows . I am using the date_time functions from boost. Everything works fine till i decided to print the date objects through the to_simple_string(date) function . I receive the below linker errors . Can you guys advise me whats wrong ? public: char const * __clrcall boost::gregorian::greg_month::as_long_string(void)const " (?as_long_string@greg_month@gregorian@boost@@$$FQBMPBDXZ) referenced in function "public: static class std::basic_ostream<char,struct std::char_traits<char> > & __clrcall boost::date_time::month_formatter<class boost::gregorian::greg_month,class boost::date_time::iso_format<char>,char>::format_month(class boost::gregorian::greg_month const &,class std::basic_ostream<char,struct std::char_traits<char> > &)" (?format_month@?$month_formatter@Vgreg_month @gregorian@boost@@V?$iso_format@D@date_time@3@D@date_time@boost@ @$$FSMAAV?$basic_ostream@DU?$char_traits@D@std@@@std@ @ABVgreg_month@gregorian@3@AAV45@@Z) 1>ADONET_Example.obj : error LNK2028: unresolved token (0A00007D) "public: char const * __clrcall boost::gregorian::greg_month::as_short_string(void)const " (?as_short_string@greg_month@gregorian@boost@@$$FQBMPBDXZ) referenced in function "public: static class std::basic_ostream<char,struct std::char_traits<char> > & __clrcall boost::date_time::month_formatter<class boost::gregorian::greg_month,class boost::date_time::iso_format<char>,char>::format_month(class boost::gregorian::greg_month const &,class std::basic_ostream<char,struct std::char_traits<char> > &)" (?format_month@?$month_formatter@Vgreg_month @gregorian@boost@@V?$iso_format@D@date_time@3@D@date_time@boost@ @$$FSMAAV?$basic_ostream@DU?$char_traits@D@std@@@std@ @ABVgreg_month@gregorian@3@AAV45@@Z) 1>ADONET_Example.obj : error LNK2019: unresolved external symbol "public: char const * __clrcall boost::gregorian::greg_month::as_long_string(void)const " (?as_long_string@greg_month@gregorian@boost@@$$FQBMPBDXZ) referenced in function "public: static class std::basic_ostream<char,struct std::char_traits<char> > & __clrcall boost::date_time::month_formatter<class boost::gregorian::greg_month,class boost::date_time::iso_format<char>,char>::format_month(class boost::gregorian::greg_month const &,class std::basic_ostream<char,struct std::char_traits<char> > &)" (?format_month@?$month_formatter@Vgreg_month @gregorian@boost@@V?$iso_format@D@date_time@3@D@date_time@boost@ @$$FSMAAV?$basic_ostream@DU?$char_traits@D@std@@@std@ @ABVgreg_month@gregorian@3@AAV45@@Z) 1>ADONET_Example.obj : error LNK2019: unresolved external symbol "public: char const * __clrcall boost::gregorian::greg_month::as_short_string(void)const " (?as_short_string@greg_month@gregorian@boost@@$$FQBMPBDXZ) referenced in function "public: static class std::basic_ostream<char,struct std::char_traits<char> > & __clrcall boost::date_time::month_formatter<class boost::gregorian::greg_month,class boost::date_time::iso_format<char>,char>::format_month(class boost::gregorian::greg_month const &,class std::basic_ostream<char,struct std::char_traits<char> > &)" (?format_month@?$month_formatter@Vgreg_month @gregorian@boost@@V?$iso_format@D@date_time@3@D@date_time@boost@ @$$FSMAAV?$basic_ostream@DU?$char_traits@D@std@@@std@ @ABVgreg_month@gregorian@3@AAV45@@Z) 1>D:\Profiles\g18244\My Documents\Visual Studio 2008\Projects\DataSet\Debug\ADONET_Example.exe : fatal error LNK1120: 4 unresolved externals

2 1

Array to List
by noman javed 30 Jul '08

30 Jul '08

I have two questions How can we convert an array (arbitrary type, arbitrary size) to mpl::list. Is there any metafunction in mpl which can do this for us ? Second is there any way to send mpl::list (or any mpl sequence) to MPI_Alltoallv without converting it into an array ?

2 1

boost program options and notifier call
by Aljaz 30 Jul '08

30 Jul '08

Hello I have boost.program_options implemented inside a config class. I want to call function (my_function) that is a member of config class for specific option (with notifier call). class config_class { public: void read_config() { po::options_description desc("Allowed options"); desc.add_options() ("help", "produce help message") ("include-path,I", po::value< vector<string> >()->notifier(&config_class::my_function), "include path"); } void my_function(vector<std::string> str) { } }; This wont compile and will give error for ..>()->notifier(&config_class::my_function)... >> error C2064: term does not evaluate to a function taking 1 arguments What am I doing wrong? Many thanks in advance! Aljaz

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boost::serialization - PHP -> c++ (fastcgi)
by Alejandro Martinez 30 Jul '08

30 Jul '08

What i need to do is this: Have a php file in a webserver, doing a POST with binary payload to a fast-cgi written in c++, and the c++ should deserialize that payload into a known struct. something like: struct whatever { int a; int b; float c; std::vector<int> d; } (mainly structs consisting of basic types and collections of basic types) I've been playing around with boost::serialization, but i can't seem to comprehend the binary format it generates (So i could hardcode the php to make a valid payload to be deserialised from the fast-cgi). And not so important: i've noticed boost::serialization to binary archives always look like: serialization::archive ÃõH@ can't i get rid of the "serialization::archive" thing that is obviusly not part of the struct i just serialized? Thanks a lot for your help. I'd appreciate any other ideas to accomplish the same result :).

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boost.asio and ncurses.h problem
by Ruben Lara 30 Jul '08

30 Jul '08

Hi all... If i try to compile boost.asio and ncurses.h together i get next problem: bermejo@BERMEJO-MOBILE ~/Proyecto/boost $ g++ -lncurses -lboost_system -lboost_thread -o main *.cpp /usr/include/boost/asio/detail/socket_option.hpp:242: error: ‘stdscr’ is not a type /usr/include/boost/asio/detail/socket_option.hpp:252: error: ‘stdscr’ is not a type /usr/include/boost/asio/detail/socket_option.hpp:252: error: expected identifier before ‘)’ token bermejo@BERMEJO-MOBILE ~/Proyecto/boost $ Problem when: #include <boost/asio.hpp> #include <ncurses.h> Any ideas? Thank you in advance Rubén Lara _________________________________________________________________ La última hora de tu ciudad en MSN Noticias http://noticias.es.msn.com/

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Boost spirit: overlapping inner struct result
by Pascal Kesseli 30 Jul '08

30 Jul '08

Hi everyone When trying to compile the serialization library for my Montavista embedded computer, I am getting a strange error message concerning boost spirit/core/primitives/numerics.hpp stating that struct result in sign_parser has already been defined before. Back then, I couldn't deny that fact, as result is already defined in sign_parser's superclass parser, so I renamed the struct in the subclass to tresult and the library compiled fine. Currently, I am asking myself what influence such a change might have on the running program. I am having unexplainable SIGABRT signals appearing and killing my program, thus I suspect my change was not that mere after all. Is there a better workaround I could use to solve this problem? Thanks in advance for your replies and best regards Pascal Kesseli PS: g++ --version is for my compiler: g++ (GCC) 3.4.3 (MontaVista 3.4.3-25.0.30.0501131 2005-07-23) Copyright (C) 2004 Free Software Foundation, Inc. Dies ist freie Software; die Kopierbedingungen stehen in den Quellen. Es gibt KEINE Garantie; auch nicht für VERKAUFBARKEIT oder FÜR SPEZIELLE ZWECKE. PPS: The compiler error message (quite self-explanatory, even though having some german phrases in it): Building file: ../xml_grammar.cpp Invoking: GCC C++ Compiler g++ -O0 -Wall -c -fmessage-length=0 -MMD -MP -MF"xml_grammar.d" -MT"xml_grammar.d" -o"xml_grammar.o" "../xml_grammar.cpp" In file included from ../basic_xml_grammar.ipp:22, from ../xml_grammar.cpp:63: /usr/local/xscale_be/bin/../target/usr/include/boost/spirit/core/primitives/numerics.hpp:122: Fehler: Deklaration von »template<class ScannerT> struct boost::spirit::sign_parser::result« /usr/local/xscale_be/bin/../target/usr/include/boost/spirit/core/parser.hpp:123: Fehler: steht mit der vorherigen Deklaration »template<class ScannerT> struct boost::spirit::parser<boost::spirit::sign_parser>::result« in Konflikt make: *** [xml_grammar.o] Fehler 1

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[serialization] : NVP macros and template classes
by Mathieu Peyréga 30 Jul '08

30 Jul '08

Hello, I have a template class as a base class I wish to serialize... In that case, the BOOST_SERIALIZATION_BASE_OBJECT_NVP does not work as it introduce < > caracters wich i guess are forbidden in the xml tag... Is there a nice way to solve this issue ? For now, I am only facing the 1 parameter case and thus defined a macro : #define BOOST_SERIALIZATION_BASE_OBJECT_TEMPLATE_NVP(classname,templateparameter) \ boost::serialization::make_nvp( \ BOOST_PP_STRINGIZE(classname)BOOST_PP_STRINGIZE(templateparameter), \ boost::serialization::base_object<classname<templateparameter> >(*this) \ ) which gives me somme acceptable behaviour... if I have ClassA<ParameterClass> as a base class I write BOOST_SERIALIZATION_BASE_OBJECT_TEMPLATE_NVP(ClassA,ParameterClass) instead of "usual" BOOST_SERIALIZATION_BASE_OBJECT_NVP(BaseClassName) Regards, Mathieu -- http://www.incub.net

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