October 2007 - Boost-users - lists.preview.boost.org

Question about versioning of serialization
by Fred Lupien 24 Oct '07

24 Oct '07

Hello, we are currently implementing serialization versioning using boost and I am curious to know if their is a way to support a changing class hierarchy. Let's say C derives from A for a while and then a change requires C to derive from B instead, which derives from A. Is it possible to support such a change provided we know what default values are needed for the new class? I tried and even if don't serialize anything in class C I get stream errors because I believe boost saves some base info for each class. When it tries to reload those value from a old stream, obviously it desynchronizes it because the values are not in the stream. So is their a way around this? Also is it possible to support the removal of a class. If, for exemple C derives from B which in turn derives from A and suddenly B is removed. Is their a way to deal with this without invalidating all previously saved data? Thank you for your help! -- Frédérick Martel-Lupien Étudiant en Génie Informatique Université de Sherbrooke fred.lupien(a)gmail.com

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dereferencing type-punned pointer in function_base under gcc-4.3
by Benoit Hudson 24 Oct '07

24 Oct '07

I'm trying to make sure my code compiles under gcc-4.3 before that compiler comes out. I'm currently stuck on an error it reports in boost, version 1.34.1 (which I downloaded seconds ago; error was also present in 1.34.0): In file included from ../boost/function/detail/prologue.hpp:16, from ../boost/function.hpp:22, from ../boost/iterator/transform_iterator.hpp:10, from [my code]: ../boost/function/function_base.hpp: In member function 'const std::type_info& boost::function_base::target_type() const': ../boost/function/function_base.hpp:485: error: dereferencing type-punned pointer will break strict-aliasing rules I don't understand how there's any type-punning going on at line 485, although to my untrained eye it looks a lot like it's returning a ref to a temporary. A couple lines later looks only very slightly fishier, but still shouldn't be breaking any aliasing rules. So I leave it to the experts to figure out what's going on here. -- Benoît

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installation on Borland Developer Studio 2006 (C++Builder)
by Harald Wolf - G. Ulmer Automation GbmH 24 Oct '07

24 Oct '07

Hi, how do i install boost with the BSD2006? The installer package seems not to work: ------my first try was------------------------------------------------------ #include "boost/date_time/gregorian/gregorian.hpp" //include all types plus i/o ... ... ---------------------------------------------------------------------------- - i get: [Linker Fataler Fehler] Fatal: Datei 'LIBBOOST_DATE_TIME-BCB-MT-D-1_34_1.LIB' kann nicht geöffnet werden since the C:\Programme\Borland\BDS\4.0\include\boost\boost_1_34_1\lib directory only has *vc* files. So i downloaded the: boost_1_34_1.zip BUT here i have to build the LIBs and i'm a C++ Newbiew! How do i build the Libs? PLEASE HELP!

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[program_options] Translating messages to another language
by Pavel Syomin 24 Oct '07

24 Oct '07

Hi to all! I am writing some application that uses program_options. This application interacts with user using non-english language. Is there any way to translate "what" messages from exceptions to another language? At now I found only one way (rather hack :) ): static void store(const basic_parsed_options<char> &options, variables_map &variables) { try { program_options::store(options, variables); } catch(unknown_option &error) { const char *what = error.what(); static const char prefix[] = "unknown option "; if(!strncmp(what, prefix, sizeof(prefix) - 1)) throw logic_error("Неизвестная опция: " + string(what + sizeof(prefix) - 1)); throw logic_error("Неверный формат командной строки"); } } Another way is to redefine function invalid_command_line_syntax::error_message(), but in such case we can translate only some messages.

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error2632:__int64 problem
by mmoges 24 Oct '07

24 Oct '07

Hi All, I am not sure if this issue has been dealt with already in this forum. But I couldn't find satisfactory answer on the Net. I am using Boost in an application that is working perfectly fine. I had to modify the application in a number of ways and I copied it to a different folder, and when I try to build it, it complains with errors and warnings that have never occured with the orignal application. Please find the error report below: c:\Boost\include\boost-1_33_1\boost\cstdint.hpp(304) : error C2632: '__int64' followed by '__int64' is illegal c:\Boost\include\boost-1_33_1\boost\cstdint.hpp(304) : warning C4091: 'typedef ' : ignored on left of '__int64' when no variable is declared c:\Boost\include\boost-1_33_1\boost\cstdint.hpp(307) : warning C4114: same type qualifier used more than once c:\Boost\include\boost-1_33_1\boost\cstdint.hpp(307) : error C2632: '__int64' followed by '__int64' is illegal c:\Boost\include\boost-1_33_1\boost\cstdint.hpp(307) : warning C4091: 'typedef ' : ignored on left of 'unsigned __int64' when no variable is declared c:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\include\xlocmon(231) : fatal error C1903: unable to recover from previous error(s); stopping compilation I am a bit puzzled by this problem. I really appreciate any help. Thank you in advance. Best regards, Metty __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Problem using Boost Graph Library - Python Bindings
by Camilo La Rota 24 Oct '07

24 Oct '07

Hello all, I have just installed the Boost Graph Library - Python Bindings. Everything seemed to be ok, I can read a graph from the example "mst.dot" file and from my own ".dot" files, I can write them back to a file. However, when I try the example script (at the end of the following page: http://www.osl.iu.edu/~dgregor/bgl-python/) -------------------------------------------------------------------- import boost.graph as bgl # Load a graph from the GraphViz file 'mst.dot' graph = bgl.Graph.read_graphviz('mst.dot') # Convert the weight into floating-point values weight = graph.convert_property_map(graph.edge_properties['weight'], 'float') ... etc ------------------------------------------------------------------- it stops at the third line with the following error: ---------------------------------------------------------------------------- Traceback (most recent call last): File "<pyshell#17>", line 1, in <module> weight = graph.convert_property_map(graph.edge_properties['weight'],'float') KeyError: 'weight' ------------------------------------------------------------------------ I receive the same error message if I write only: graph.edge_properties['weight'] The content of the example mst.dot file is: -------------------------------------------------- graph G { A -- C [weight="1.0"] B -- D [weight="1.0"] B -- E [weight="2.0"] C -- B [weight="7.0"] C -- D [weight="3.0"] D -- E [weight="1.0"] E -- A [weight="1.0"] E -- B [weight="1.0"] } -------------------------------------------------- Does any one have any idea about the source of this error. Thanks a lot in advance, Camilo

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seeding a boost::random number generator...?
by Graham Reitz 24 Oct '07

24 Oct '07

I am little confused on how to see a random generator. What am I missing? // Grab the seed HighResTimer::Time time_secs = high_res_timer.getTime(); // Go ahead and truncate, it's just a seed boost::int32_t time = static_cast<boost::int32_t>(time_secs * 100000); // produces randomness out of thin air // see pseudo-random number generators boost::mt19937 rng; rng.seed(); // How do you seed this with the time? // distribution that maps to 0..1 // see random number distributions boost::uniform_real<> zero_to_one(0,1); // glues randomness with mapping boost::variate_generator<boost::mt19937&, boost::uniform_real<> > be_random zero_to_one);

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Re: [Boost-users] Thread Library Problem
by Andres Herrera 23 Oct '07

23 Oct '07

Thanks Raul, that worked like a charm. I feel really dumb now, I tried including pthread in the code not the make file. Thanks again, Andres Herrera -----Original Message----- From: boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of raulh39(a)ya.com Sent: Tuesday, October 23, 2007 1:17 PM To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] Thread Library Problem On Tue, 23 Oct 2007 09:55:05 -0700 "Andres Herrera" <aherrera(a)MarchNetworks.com> wrote: > Hi, > ... > g++ TestBoost.cpp -o listener -I > /home/andresh/DVRTranslators/Boost/include/boost-1_34_1/ > /home/andresh/DVRTranslators/Boost/lib/libboost_thread-gcc41-mt-d.a > Try to add -pthread: g++ -pthread TestBoost.cpp -o listener \ -I/home/andresh/DVRTranslators/Boost/include/boost-1_34_1 \ /home/andresh/DVRTranslators/Boost/lib/libboost_thread-gcc41-mt-d.a HTH, Raul. _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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Thread Library Problem
by Andres Herrera 23 Oct '07

23 Oct '07

Hi, I'm new to Boost, I've been trying to use the Thread library that boost offers. I'm on a Kubuntu 7.1 box using G++ 4.1 Compiler with Boost 1.34. I've only been successful compiling my project when including libboost_thread-gcc41-mt-d.so library file. I would much rather use the .a file however, If I try to use the libboost_thread-gcc41-mt-d.a library file, i get the following errors: /home/andresh/DVRTranslators/Boost/lib/libboost_thread-gcc41-mt-d.a(thre ad.o): In function `boost::thread::join()': /home/andresh/DVRTranslators/Boost/boost_1_34_1/libs/thread/src/thread.c pp:226: undefined reference to `pthread_join' /home/andresh/DVRTranslators/Boost/lib/libboost_thread-gcc41-mt-d.a(thre ad.o): In function `~thread': /home/andresh/DVRTranslators/Boost/boost_1_34_1/libs/thread/src/thread.c pp:191: undefined reference to `pthread_detach' /home/andresh/DVRTranslators/Boost/boost_1_34_1/libs/thread/src/thread.c pp:191: undefined reference to `pthread_detach' /home/andresh/DVRTranslators/Boost/lib/libboost_thread-gcc41-mt-d.a(thre ad.o): In function `thread': /home/andresh/DVRTranslators/Boost/boost_1_34_1/libs/thread/src/thread.c pp:156: undefined reference to `pthread_create' /home/andresh/DVRTranslators/Boost/boost_1_34_1/libs/thread/src/thread.c pp:156: undefined reference to `pthread_create' /home/andresh/DVRTranslators/Boost/lib/libboost_thread-gcc41-mt-d.a(mute x.o): In function `boost::try_mutex::do_trylock()': /home/andresh/DVRTranslators/Boost/boost_1_34_1/libs/thread/src/mutex.cp p:260: undefined reference to `pthread_mutex_trylock' collect2: ld returned 1 exit status make: *** [listener] Error 1 I've used the Regex and Filesystem .a library files without a problem, but the Thread .a library file won't work. Here is my code: #include <boost/thread/thread.hpp> #include <iostream> void helloworld() { std::cout << "Hello World!" << std::endl; } int main() { std::cout << "STARTING "; boost::thread thrd(&helloworld); thrd.join(); helloworld(); return 0; } Here is my MakeFile: all: listener listener: TestBoost.cpp g++ TestBoost.cpp -o listener -I /home/andresh/DVRTranslators/Boost/include/boost-1_34_1/ /home/andresh/DVRTranslators/Boost/lib/libboost_thread-gcc41-mt-d.a Any help is greatly appreciated. If you need any more information please ask, I want to try and get this problem resolved soon. Thanks, Andres

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Re: [Boost-users] boost::serialization Is there any way to get rid ofcompiler warnings(C4103, ...) on VC++ 2005?
by "JOAQUIN LOPEZ MU?Z" 23 Oct '07

23 Oct '07

----- Mensaje original ----- De: Oleg Udovenko <oleg(a)enginia.com> Fecha: Martes, Octubre 23, 2007 8:31 pm Asunto: [Boost-users] boost::serialization Is there any way to get rid ofcompiler warnings(C4103, ...) on VC++ 2005? Para: boost-users(a)lists.boost.org > Hi, > > I'm compiling the examples from the boost::serialization library with > VC++ 2005, and getting a lot of warnings, they are quite annoying. > > How can I get rid of them? [...] > 1>C:\WORK\STL\boost\boost_1_34_1 \boost/serialization/collections_save_im > p.hpp(38) : warning C4267: 'initializing' : conversion from > 'size_t' to 'unsigned int', possible loss of data [...] This looks like the same issue as described at http://lists.boost.org/boost-users/2006/03/18075.php with respect to warnings C4312/C4311, basically an oversmart warning triggered by the /Wp64 mode? Is this guess compatible with your environment? If so, the warning can be suppressed without external side effects as shown in http://tinyurl.com/2jpk4b . HTH, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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