November 2005 - Boost-users

Boost.python serialization
by Drumheller, Michael 29 Nov '05

29 Nov '05

I'm just getting started with trying to serialize some Python and C++ objects that are glued together with Boost.Python. Would it be fair to say that this link <<http://mail.python.org/pipermail/c++-sig/2004-September/008044.html>> represents the "standard" approach to this? Thanks, MD

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date_time library throwing a lot of warnings
by A Johan 29 Nov '05

29 Nov '05

Good day everyone, i'm using the boost::date_time::posix_time libarary in my application. When ever i compile i get lots of warning. mostly its about not being able to generate copy constructors from the lexical_cast lbrary and a whole lot of "C4127 conditional experssion is constant. OS: windows 2000 server Compiler: MSVC 7.1 is this normal or am i missing something here? the boost lib was compiled with the msvc_71 toolset. D:\boost_1_33_0\boost\lexical_cast.hpp(191) : warning C4511: 'boost::detail::lexical_stream<Target,Source>' : copy constructor could not be generated with [ Target=short, Source=NewSource ] D:\boost_1_33_0\boost\lexical_cast.hpp(218) : see reference to class template instantiation 'boost::detail::lexical_stream<Target,Source>' being compiled with [ Target=short, Source=NewSource ] D:\boost_1_33_0\boost\date_time\time_parsing.hpp(201) : see reference to function template instantiation 'Target boost::lexical_cast<short,Type>(const Source &)' being compiled with [ Target=short, Type=std::string, Source=std::string ] D:\boost_1_33_0\boost\date_time\time_parsing.hpp(275) : see reference to function template instantiation 'time_duration boost::date_time::parse_undelimited_time_duration<time_duration>(const std::string &)' being compiled with [ time_duration=time_duration ] D:\boost_1_33_0\boost\date_time\posix_time\time_parsers.hpp(35) : see reference to function template instantiation 'time_type boost::date_time::parse_iso_time<boost::posix_time::ptime>(const std::string &,char)' being compiled with [ time_type=boost::posix_time::ptime ] D:\boost_1_33_0\boost\lexical_cast.hpp(191) : warning C4512: 'boost::detail::lexical_stream<Target,Source>' : assignment operator could not be generated with [ Target=short, Source=NewSource ] D:\boost_1_33_0\boost\lexical_cast.hpp(137) : warning C4127: conditional expression is constant D:\boost_1_33_0\boost\lexical_cast.hpp(133) : while compiling class-template member function 'boost::detail::lexical_stream<Target,Source>::lexical_stream(void)' with [ Target=short, Source=NewSource ] D:\boost_1_33_0\boost\lexical_cast.hpp(218) : see reference to class template instantiation 'boost::detail::lexical_stream<Target,Source>' being compiled with [ Target=short, Source=NewSource ] D:\boost_1_33_0\boost\date_time\time_parsing.hpp(201) : see reference to function template instantiation 'Target boost::lexical_cast<short,Type>(const Source &)' being compiled with [ Target=short, Type=std::string, Source=std::string ] D:\boost_1_33_0\boost\lexical_cast.hpp(139) : warning C4127: conditional expression is constant cheers.

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Re: [Boost-users] How to find type boost::variant is holding?
by Merrill Cornish 29 Nov '05

29 Nov '05

Bruno, Thanks, Merrill

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How to find type boost::variant is holding?
by Merrill Cornish 28 Nov '05

28 Nov '05

If I have a boost::variant variable holding either of two types, is there a simple test to determine which type it is currently holding? Yes, I know that the object-oriented way to to avoid testing for types at runtime, but a simple if-test would work very well in the code. I've seen the static_visitor example, and that would work, but it hides the type determination and type-specific actions inside another class (or at least other functions). Yes, that would work logically, but the code needing to make this determination would be much clearer is written simply as a if-the-else based on the current type of the variant variable. Merrill

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libferris problem with boost
by brussels 28 Nov '05

28 Nov '05

Please help me with the issue described below --- Forwarded message -- From: brussels <brussels(a)yandex.ru> To: <witme-ferris(a)lists.sourceforge.net> Date: 27.11.05 22:31 Subject: No subject I trying to build libferris-1.1.70 from source. The library is building and linking without errors, but when we going to build tests and apps i get errors like this make[2]: Entering directory `/usr/home/quark/build/libferris-1.1.70/tests/regression/relativePaths' /bin/sh ../../../libtool --tag=CXX --mode=link g++ -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -I/usr/local/include/stlport -I/usr/local/lib/sigc++-1.2/include -I/usr/local/include/sigc++-1.2 -DMAX_SMALL_OBJECT_SIZE=0 -DDEFAULT_CHUNK_SIZE=4096 -I/usr/local/include -I/usr/local/include/FerrisLoki -I/usr/local/include/stlport -g -O2 -I/usr/include/xfs -O3 -DNDEBUG -I/nothing -DG_DISABLE_ASSERT -ffast-math -DFERRIS_HAVE_EET -DFERRIS_HAVE_GDBM -I/usr/home/quark/build/libferris-1.1.70/Ferris -I/usr/local/include -I/usr/local/include -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -I/usr/local/include/STLdb4 -I/usr/local/include/stlport -I/usr/local/include -I/usr/local/include/FerrisLoki -I/usr/local/include/FerrisStreams -I/usr/local/lib/sigc++-1.2/include -I/usr/local/include/sigc++-1.2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -L/usr/local/lib -L/usr/local/lib -L/usr/local/lib -lxerces-c -lxerces-depdom -L/usr/local/lib -lxalan-c -o relativePaths -Wl,--export-dynamic -lgmodule-2.0 -ldl -lgobject-2.0 -lglib-2.0 relativePaths.o -lpopt /usr/home/quark/build/libferris-1.1.70/Ferris/libferris.la -L/usr/local/qt/lib -lqt -lXext -lX11 -lm -lSM -lICE -ldl -ljpeg g++ -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -I/usr/local/include/stlport -I/usr/local/lib/sigc++-1.2/include -I/usr/local/include/sigc++-1.2 -DMAX_SMALL_OBJECT_SIZE=0 -DDEFAULT_CHUNK_SIZE=4096 -I/usr/local/include -I/usr/local/include/FerrisLoki -I/usr/local/include/stlport -g -O2 -I/usr/include/xfs -O3 -DNDEBUG -I/nothing -DG_DISABLE_ASSERT -ffast-math -DFERRIS_HAVE_EET -DFERRIS_HAVE_GDBM -I/usr/home/quark/build/libferris-1.1.70/Ferris -I/usr/local/include -I/usr/local/include -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -I/usr/local/include/STLdb4 -I/usr/local/include/stlport -I/usr/local/include -I/usr/local/include/FerrisLoki -I/usr/local/include/FerrisStreams -I/usr/local/lib/sigc++-1.2/include -I/usr/local/include/sigc++-1.2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -o .libs/relativePaths -Wl,--export-dynamic relativePaths.o -L/usr/local/lib /usr/home/quark/build/libferris-1.1.70/Ferris/.libs/libferris.so -L/usr/local/qt/lib -L/usr/X11R6/lib -L/usr/i486-slackware-linux/bin -L/usr/i486-slackware-linux/lib -L/usr/lib/gcc-lib/i486-slackware-linux/../../../i486-slackware-linux/lib -L/usr/lib/gcc-lib/i486-slackware-linux/../.. /usr/lib/libfreetype.so /usr/lib/libexpat.so /usr/local/lib/libfampp.so /usr/local/lib/libfam.so -lxerces-c -lxerces-depdom -lxalan-c /usr/local/lib/libfile.so -lssl /usr/local/lib/libstldb4.so /usr/local/lib/libferrisstreams.so /usr/local/lib/libsigc-1.2.so /usr/local/lib/libferrisloki.so /usr/lib/libgmodule-2.0.so /usr/lib/libgobject-2.0.so /usr/lib/libglib-2.0.so -lstlport_gcc -luuid /usr/lib/librpm.so -L/usr/lib /usr/lib/librpmdb.so /usr/lib/librpmio.so -lrt -lpthread -lbz2 /usr/lib/libpopt.so /usr/local/lib/libgpgme.so /usr/local/lib/libgpg-error.so /usr/local/lib/librdf.so /usr/local/lib/librasqal.so /usr/local/lib/libraptor.so /usr/lib/libxslt.so /usr/lib/libxml2.so -lz /usr/lib/libdb-4.2.so -lcrypto -lboost_wserialization-gcc -lboost_serialization-gcc /usr/lib/./libstdc++.so /usr/local/qt-x11-free-3.3.5/lib/libqt. so -lXrender -lXrandr -lXcursor -lXinerama -lXft /usr/local/lib/libfreetype.so /usr/X11R6/lib/libfontconfig.so -lXext -lX11 -lm -lSM -lICE -ldl -ljpeg -Wl,--rpath -Wl,/usr/home/quark/build/libferris-1.1.70/Ferris/.libs -Wl,--rpath -Wl,/usr/lib/. -Wl,--rpath -Wl,/usr/local/qt-x11-free-3.3.5/lib -Wl,--rpath -Wl,/usr/lib/. -Wl,--rpath -Wl,/usr/local/qt-x11-free-3.3.5/lib /usr/home/quark/build/libferris-1.1.70/Ferris/.libs/libferris.so: undefined reference to `boost::archive::basic_binary_iprimitive<boost::archive::binary_iarchive, _STL::basic_istream<char, _STL::char_traits<char> > >::basic_binary_iprimitive[not-in-charge](_STL::basic_istream<char, _STL::char_traits<char> >&, bool)' /usr/local/lib/libferrisloki.so: undefined reference to `sigc::trackable::~trackable [not-in-charge]()' /usr/local/lib/libferrisloki.so: undefined reference to `sigc::slot_base::slot_base[in-charge](sigc::slot_base const&)' /usr/local/lib/libferrisloki.so: undefined reference to `sigc::internal::signal_impl::sweep()' /usr/home/quark/build/libferris-1.1.70/Ferris/.libs/libferris.so: undefined reference to `boost::archive::basic_binary_iprimitive<boost::archive::binary_iarchive, _STL::basic_istream<char, _STL::char_traits<char> > >::load(_STL::basic_string<char, _STL::char_traits<char>, _STL::allocator<char> >&)' /usr/home/quark/build/libferris-1.1.70/Ferris/.libs/libferris.so: undefined reference to `VTT for FerrisLoki::Handlable' /usr/home/quark/build/libferris-1.1.70/Ferris/.libs/libferris.so: undefined reference to `boost::archive::basic_binary_oprimitive<boost::archive::binary_oarchive, _STL::basic_ostream<char, _STL::char_traits<char> > >::~basic_binary_oprimitive [not-in-charge]()' /usr/local/lib/libferrisloki.so: undefined reference to `sigc::slot_base::slot_base[in-charge]()' /usr/local/lib/libferrisloki.so: undefined reference to `sigc::slot_base::~slot_base [in-charge]()' /usr/local/lib/libferrisloki.so: undefined reference to `sigc::trackable::trackable[not-in-charge]()' /usr/home/quark/build/libferris-1.1.70/Ferris/.libs/libferris.so: undefined reference to `boost::archive::basic_binary_oprimitive<boost::archive::binary_oarchive, _STL::basic_ostream<char, _STL::char_traits<char> > >::save(_STL::basic_string<char, _STL::char_traits<char>, _STL::allocator<char> > const&)' /usr/home/quark/build/libferris-1.1.70/Ferris/.libs/libferris.so: undefined reference to `boost::archive::basic_binary_oprimitive<boost::archive::binary_oarchive, _STL::basic_ostream<char, _STL::char_traits<char> > >::init()' /usr/local/lib/libferrisloki.so: undefined reference to `sigc::signal_base::signal_base[not-in-charge]()' /usr/home/quark/build/libferris-1.1.70/Ferris/.libs/libferris.so: undefined reference to `boost::archive::basic_binary_oprimitive<boost::archive::binary_oarchive, _STL::basic_ostream<char, _STL::char_traits<char> > >::basic_binary_oprimitive[not-in-charge](_STL::basic_ostream<char, _STL::char_traits<char> >&, bool)' /usr/home/quark/build/libferris-1.1.70/Ferris/.libs/libferris.so: undefined reference to `boost::archive::basic_binary_iprimitive<boost::archive::binary_iarchive, _STL::basic_istream<char, _STL::char_traits<char> > >::init()' /usr/home/quark/build/libferris-1.1.70/Ferris/.libs/libferris.so: undefined reference to `boost::archive::basic_binary_iprimitive<boost::archive::binary_iarchive, _STL::basic_istream<char, _STL::char_traits<char> > >::~basic_binary_iprimitive [not-in-charge]()' collect2: ld returned 1 exit status make[2]: *** [relativePaths] Error 1 make[2]: Leaving directory `/usr/home/quark/build/libferris-1.1.70/tests/regression/relativePaths' make[1]: *** [all-recursive] Error 1 make[1]: Leaving directory `/usr/home/quark/build/libferris-1.1.70/tests/regression' make: *** [all-recursive] Error 1 I use boost 1_33_1 and gcc 3.3.6 and linux 2.4.31 Any help appreciated.. Thank you --- End of forwarded message -- -- Яндекс.Почта: объем почтового ящика не ограничен! http://mail.yandex.ru/monitoring/

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[counting_iterator] restriction/bug in distance_to()
by Martin Weigel 28 Nov '05

28 Nov '05

Hi, counting_iterator.hpp defines the distance_to() member function as follows (from CVS HEAD), template <class OtherIncrementable> difference_type distance_to(counting_iterator<OtherIncrementable> const& y) const { ... Since the argument counting_iterator<OtherIncrementable> uses the default values for CategoryOrTraversal and Difference, this distance_to() template does not apply for counting_iterator's with other than the default values for CategoryOrTraversal and Difference. In particular, for a counting_iterator with non-default CategoryOrTraversal or Difference, the necessary function typedef counting_iterator<Incrementable, CategoryOrTraversal, Distance> it_type; it_type::distance_to(it_type const&) cannot be instantiated from the above template, resulting in a compile-time error. Best, Martin

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[serialization] pointer derived from an abstract templated class
by codeur＠altern.org 28 Nov '05

28 Nov '05

Hello, I know the question has already been asked (http://groups.google.com/group/boost-list/browse_thread/thread/9e1bcbd7c4f7…) but without answers. So I retry.. Is it possible to serialize an object that inherits from a templated abstract class ? For instance : template<typename T> class base { }; template<typename T> class Impl : public base<T> { }; int main(/* ... */) { base *b = new Impl(type); // how can we serialize b ? } Thanks for your help.

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scoped_ptr faq
by Bruno Martínez 28 Nov '05

28 Nov '05

Hi. I had the same question that is answered there, but the answer didn't fit my problem. I'm using scoped_ptr<node> inside node itself, so node is incomplete at the point of use. That forbids using auto_ptr, IIUC. I think it would be good to add to the answer: Q. Why doesn't scoped_ptr have a release() member? A. When reading source code, it is valuable to be able to draw conclusions about program behavior based on the types being used. If scoped_ptr had a release() member, it would become possible to transfer ownership of the held pointer, weakening its role as a way of limiting resource lifetime to a given context. Use std::auto_ptr where transfer of ownership is required, or shared_ptr if incomplete type support is needed. "or shared_ptr if incomplete type support is needed." is mine. How's that? Regards, Bruno

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How to compile boost in Borland c++ Builder 6
by pes nemarn 28 Nov '05

28 Nov '05

As subject says - I am in need of information about on how to compile boost in Borland c++ Builder 6 on operation system Windows XP. I have been searching everywhere, instructions are either too complicated or badly written - in any case I still havent found the answer. I hope you'll help me, I'm realy stuck and you guys are probably my last resort. Looking forward to answers or hints, cheers.

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serialization: handling variable length data
by __PPS__ 27 Nov '05

27 Nov '05

in simplest case std::string is serialized this way: length|string data. in this case it's possible to feed invalid data to deserialization function so that application stalls waiting for the os to reserve huge pile or ram, or fails with bad alloc. this invalid data could be intentionally manually edited or as well it could be the case where you serialize ints and then try to deserialize data as strings (or whatever else). isn't it possible to have archives such check somehow the size of available stream data. (eg, for stringstream), or archives that initialized with a data pointer and the size of the data pointed by that pointer or maybe something else here's a complete example that shows such problem in action ///////////////////////////// #include <iostream> #include <fstream> #include <string> #include <ctime> #include <boost/archive/text_oarchive.hpp> #include <boost/archive/binary_iarchive.hpp> #include <boost/serialization/serialization.hpp> using namespace std; using namespace boost::archive; int main()try{ string s1 = "Hello world!", s2; { ofstream file("data.txt", ios::binary | ios::trunc); text_oarchive a(file, no_header); a << s1; } time_t t(time(0)); { ifstream file("data.txt", ios::binary); binary_iarchive a(file, no_header); a >> s2; } cout << "time elapsed: " << (time(0)-t) << "s" << endl; cout << "s2.size() => " << s2.size() << "\n" "s2 => \"" << s2.substr(0,64) << "...\"" << endl; }catch(const exception &e){ cout << "error: " << e.what() << endl; } ///////////////////////////// and the output I got on win xp: time elapsed: 110s s2.size() => 1210069553 s2 => "ello world! ..."

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