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

[preporcessor]Can we use BOOST_PP_SEQ_FOLD_LEFT on sequences with one element?
by vicente.botet 10 Jul '08

10 Jul '08

Hello, I'm a beginer with the preprocessor library. My goal is to generate from a sequence (a)(b)(c) => a::b::c and from (a) => a I have tried with the following code #include <boost/preprocessor/seq/fold_left.hpp> #include <boost/preprocessor/seq/head.hpp> #include <boost/preprocessor/seq/tail.hpp> #define NAME(s, state, x) state::x BOOST_PP_SEQ_FOLD_LEFT(NAME, BOOST_PP_SEQ_HEAD((a)(b)), BOOST_PP_SEQ_TAIL((a)(b))) BOOST_PP_SEQ_FOLD_LEFT(NAME, BOOST_PP_SEQ_HEAD((a)), BOOST_PP_SEQ_TAIL((a))) It works well with sequences with more than 1 element but with a sequence with only an element it fails, having the following preprocessor output (error?) a::b test.cpp:8:1: macro "BOOST_PP_SEQ_ELEM_III" requires 2 arguments, but only 1 given a::BOOST_PP_SEQ_ELEM_III What I'm missing? Thanks in advance, Vicente

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Re: [Boost-users] Boost.Threads for Fedora/Wine
by Michael Ost 10 Jul '08

10 Jul '08

On Wed, 09 Jul 2008 08:27:39 +0100, Anthony Williams <anthony.ajw(a)gmail.com> wrote: > First off, put threadapi=win32 on your bjam command line. This will > ensure the libraries are named differently to the pthread ones, and > won't define the macros that force pthreads. > > Next, ensure that _WIN32 is defined (e.g. add -D_WIN32 to <compileflags> > for > your compiler in user-config.jam) > > I wouldn't recommend trying to use some pthreads and some win32 builds > of boost libs in the same app: if they use any boost.thread facilities > then the definitions are different between the two APIs > (e.g. structure of boost::mutex). Good point. And building boost with winegcc adds a whole secondary translation layer which bypasses any optimizations the boost developers have done. >From queries to the wine-devel list, the problem is that Wine needs to know about threads being created. So I might be able to work with that. Thanks for the help... mo

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Performance and linking (boost_regex)
by SD 10 Jul '08

10 Jul '08

Hi, i've encountered a significant performance difference with boost_regex between linking first to it and linking last to it. I guess it is not a issue specific to boost_regex, but maybe someone can clarify that. I have created the following test files and tested with gcc-4.1 and gcc-4.3 on 64-bit linux and gcc-4.1.2 on 32-bit linux. The results for 64bit are further down, but the results for 32-bit are very similar. **** # set your boost_extension (i.e. -mt) # export BOOST_EXT=-mt cat > test.hpp <<EOF // test.hpp #ifndef TEST #define TEST #include <string> int check(const std::string & test); #endif // TEST EOF cat > test.cpp <<EOF // test.cpp #include "test.hpp" #include <boost/regex.hpp> int check(const std::string & test) { int result = 0; static boost::regex match("a*b*c*d*e*f*g*h*i*j*k*a*b*c*d*e*f*g*h*i*a*b*c*d*e*f*g*h*i*j*"); for (int i = 0; i < 1000; ++i) { result += boost::regex_match(test, match); } return result; } EOF cat > main.cpp <<EOF // main.cpp #include "test.hpp" #include <iostream> int main() { std::cout << check("abcdaaaaaaaaaabcdefgaaaaaaaaaaabbbbbbbbbddeef") << std::endl; } EOF # Create libtest.so g++ -shared -fPIC test.cpp -o libtest.so # link boost_regex before libtest.so g++ main.cpp -lboost_regex${BOOST_EXT} -ltest -L${PWD} -o main_fast # link boost_regex after libtest.so g++ main.cpp -ltest -lboost_regex${BOOST_EXT} -L${PWD} -o main_slow time env LD_LIBRARY_PATH=${PWD} ./main_slow # real 0m0.753s, user 0m0.746s, sys 0m0.004s time env LD_LIBRARY_PATH=${PWD} ./main_fast # real 0m0.104s, user 0m0.103s, sys 0m0.002s As the results show the order which libs are being linked to the program has significant performance impacts on execution time: main_fast is about 7 times faster than main_slow. **** Interestingly main_slow becomes much faster, if you compile libtest.so with optimization. With -O the execution time of main_slow becomes: g++ -O -shared -fPIC test.cpp -o libtest.so time env LD_LIBRARY_PATH=${PWD} ./main_slow # real 0m0.118s, user 0m0.115s, sys 0m0.003s But it is still about 15% slower than main_fast. **** If you compile test.cpp statically into the executable you also get slow results g++ main.cpp test.cpp -o main_test -l boost_regex time ./main_test # real 0m0.645s, user 0m0.641s, sys 0m0.001s **** If you compile an optimized version of main_test on my 64-bit linux you also get about 10% worse runtime than the unoptimized version of main_fast. With 32-bit however main_test runs faster than main_fast. g++ -O2 main.cpp test.cpp -o main_test -l boost_regex time ./main_test # real 0m0.113s, user 0m0.111s, sys 0m0.001s **** I would appreciate if someone could explain these surprising results. Regards Stefan

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Unresolved symbols to ~archive_pointer_oserializer using serialization
by Christoph Mayer 10 Jul '08

10 Jul '08

Hi, I am in the progress of upgrading a project from boost 1.34.0 to 1.35.0. As far as I can see no changes have been made to the Serialization library. But I am having trouble with it. -I build boost using ./configure and using the with-libraries option to built the serialization library, besides others as a shared library -I am using g++ 4.2.3 on Ubuntu 8.04 Using BOOST_CLASS_EXPORT_GUID I am making my classes known to the serialization library. For serialization I am using boost::archive::polymorphic_binary_oarchive. This all worked with 1.34.0. Now I am getting strange linker errors. I do have -lboost_serialization on the linker command. When I uncomment all BOOST_CLASS_EXPORT_GUID commands my compilation works. Following are the linker errors: RemoteMessagingSystem.o: In function `~pointer_iserializer': /home/mayer/SpoVNet/development/spovnet/lib/boost_1_35_0/build/include/boost-1_35/boost/archive/detail/iserializer.hpp:171: undefined reference to `boost::archive::detail::archive_pointer_iserializer<boost::archive::polymorphic_binary_iarchive>::~archive_pointer_iserializer()' RemoteMessagingSystem.o: In function `~pointer_oserializer': /home/mayer/SpoVNet/development/spovnet/lib/boost_1_35_0/build/include/boost-1_35/boost/archive/detail/oserializer.hpp:162: undefined reference to `boost::archive::detail::archive_pointer_oserializer<boost::archive::detail::polymorphic_oarchive_dispatch<boost::archive::binary_oarchive_impl<boost::archive::binary_oarchive, char, std::char_traits<char> > > >::~archive_pointer_oserializer()' RemoteMessagingSystem.o: In function `~pointer_iserializer': /home/mayer/SpoVNet/development/spovnet/lib/boost_1_35_0/build/include/boost-1_35/boost/archive/detail/iserializer.hpp:171: undefined reference to `boost::archive::detail::archive_pointer_iserializer<boost::archive::polymorphic_binary_iarchive>::~archive_pointer_iserializer()' /home/mayer/SpoVNet/development/spovnet/lib/boost_1_35_0/build/include/boost-1_35/boost/archive/detail/iserializer.hpp:171: undefined reference to `boost::archive::detail::archive_pointer_iserializer<boost::archive::polymorphic_binary_iarchive>::~archive_pointer_iserializer()' RemoteMessagingSystem.o: In function `~pointer_oserializer': /home/mayer/SpoVNet/development/spovnet/lib/boost_1_35_0/build/include/boost-1_35/boost/archive/detail/oserializer.hpp:162: undefined reference to `boost::archive::detail::archive_pointer_oserializer<boost::archive::detail::polymorphic_oarchive_dispatch<boost::archive::binary_oarchive_impl<boost::archive::binary_oarchive, char, std::char_traits<char> > > >::~archive_pointer_oserializer()' /home/mayer/SpoVNet/development/spovnet/lib/boost_1_35_0/build/include/boost-1_35/boost/archive/detail/oserializer.hpp:162: undefined reference to `boost::archive::detail::archive_pointer_oserializer<boost::archive::detail::polymorphic_oarchive_dispatch<boost::archive::binary_oarchive_impl<boost::archive::binary_oarchive, char, std::char_traits<char> > > >::~archive_pointer_oserializer()' RemoteMessagingSystem.o: In function `pointer_oserializer': /home/mayer/SpoVNet/development/spovnet/lib/boost_1_35_0/build/include/boost-1_35/boost/archive/detail/oserializer.hpp:214: undefined reference to `boost::archive::detail::archive_pointer_oserializer<boost::archive::detail::polymorphic_oarchive_dispatch<boost::archive::binary_oarchive_impl<boost::archive::binary_oarchive, char, std::char_traits<char> > > >::archive_pointer_oserializer(boost::serialization::extended_type_info const&)' /home/mayer/SpoVNet/development/spovnet/lib/boost_1_35_0/build/include/boost-1_35/boost/archive/detail/oserializer.hpp:224: undefined reference to `boost::archive::detail::archive_pointer_oserializer<boost::archive::detail::polymorphic_oarchive_dispatch<boost::archive::binary_oarchive_impl<boost::archive::binary_oarchive, char, std::char_traits<char> > > >::~archive_pointer_oserializer()' /home/mayer/SpoVNet/development/spovnet/lib/boost_1_35_0/build/include/boost-1_35/boost/archive/detail/oserializer.hpp:214: undefined reference to `boost::archive::detail::archive_pointer_oserializer<boost::archive::detail::polymorphic_oarchive_dispatch<boost::archive::binary_oarchive_impl<boost::archive::binary_oarchive, char, std::char_traits<char> > > >::archive_pointer_oserializer(boost::serialization::extended_type_info const&)' /home/mayer/SpoVNet/development/spovnet/lib/boost_1_35_0/build/include/boost-1_35/boost/archive/detail/oserializer.hpp:224: undefined reference to `boost::archive::detail::archive_pointer_oserializer<boost::archive::detail::polymorphic_oarchive_dispatch<boost::archive::binary_oarchive_impl<boost::archive::binary_oarchive, char, std::char_traits<char> > > >::~archive_pointer_oserializer()' RemoteMessagingSystem.o: In function `pointer_iserializer': /home/mayer/SpoVNet/development/spovnet/lib/boost_1_35_0/build/include/boost-1_35/boost/archive/detail/iserializer.hpp:314: undefined reference to `boost::archive::detail::archive_pointer_iserializer<boost::archive::polymorphic_binary_iarchive>::archive_pointer_iserializer(boost::serialization::extended_type_info const&)' /home/mayer/SpoVNet/development/spovnet/lib/boost_1_35_0/build/include/boost-1_35/boost/archive/detail/iserializer.hpp:323: undefined reference to `boost::archive::detail::archive_pointer_iserializer<boost::archive::polymorphic_binary_iarchive>::~archive_pointer_iserializer()' /home/mayer/SpoVNet/development/spovnet/lib/boost_1_35_0/build/include/boost-1_35/boost/archive/detail/iserializer.hpp:314: undefined reference to `boost::archive::detail::archive_pointer_iserializer<boost::archive::polymorphic_binary_iarchive>::archive_pointer_iserializer(boost::serialization::extended_type_info const&)' /home/mayer/SpoVNet/development/spovnet/lib/boost_1_35_0/build/include/boost-1_35/boost/archive/detail/iserializer.hpp:323: undefined reference to `boost::archive::detail::archive_pointer_iserializer<boost::archive::polymorphic_binary_iarchive>::~archive_pointer_iserializer()' collect2: ld returned 1 exit status Any help is appreciated as I am slightly going nuts :) Best regards, Chris

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Is there an elegant way to initialize an instance of boost::any with a C-style string constant?
by Ferdinand Prantl 10 Jul '08

10 Jul '08

Hello, I would like to ask you about the best solution to initialize a boost::any instance with a C-string constant. Both the most legible (IMHO) possibilities fail: boost::any foo("foo"); boost::any bar; bar = "bar"; Compiler (MSVC 2008 in my case) complains about them: ...\boost\any.hpp(117) : error C2536: 'boost::any::holder<ValueType>::boost::any::holder<ValueType>::held' : cannot specify explicit initializer for arrays with [ ValueType=const char [4] ] ...\boost\any.hpp(134) : see declaration of 'boost::any::holder<ValueType>::held' with [ ValueType=const char [4] ] ...\boost\any.hpp(115) : while compiling class template member function 'boost::any::holder<ValueType>::holder(ValueType (&))' with [ ValueType=const char [4] ] ...\boost\any.hpp(41) : see reference to class template instantiation 'boost::any::holder<ValueType>' being compiled with [ ValueType=const char [4] ] ...\test.cpp(10) : see reference to function template instantiation 'boost::any::any<const char[4]>(ValueType (&))' being compiled with [ ValueType=const char [4] ] Obviously the string constant is considered of the type chat[4] which lacks CopyConstructible and Assignable requirements. Wrapping the constant in some expression which satisfies the requiremenst spoils the beauty of a simple code or brings unnecessary (for the constant handling) object: boost::any foo(static_cast<const char *>("foo")); boost::any foo(std::string("foo")); Such solutions were suggested in the thread http://lists.boost.org/Archives/boost/2003/01/43460.php but I was hoping there could be something better. I suppose there is no way to persuade the compiler to consider the constant to be const char *... Why has not been the following constructor added to boost::any? The array would make it there passing just one conversion: template<typename ValueType> any(const ValueType * value) : content(new holder<const ValueType *>(value)) {} Someone could say that that it is more error prone because it enables storing a pointer which can be invalid as soon as the boost::any instance leaves the scope but the error can be made anyway: boost::any foo(std::string("foo").c_str()); Another possibility would be to match the array type exactly but it has probably no benefit: template<typename ValueType> any(const ValueType value []) : content(new holder<const ValueType *>(value)) {} Do you see any problems with such constructors? How do you use string constants with boost::any? Thank you, Ferda Prantl

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[Boost.Serialization] Derived class de-serialization problem due to MSVC linker
by Markus.Himmerich＠oppenheim.de 10 Jul '08

10 Jul '08

Hi, I am trying to serialize a large set of objects in our library. I am using the Serialization library from version 1.33 with MSVC 2003. When I had all serialization code in the header files of the classes, linking took too much time and memory. Therefore I am now using explicit template instantiation of the serialize function (see below) in conjunction with precompiled headers for the Boost.Serialization. The problem is this: When I de-serialize a DerivedObject to a BaseObject-pointer (so that only the header of the BaseObject class is included) the linker seems to throw away the information from the explicit template instantiation of the DerivedObject in some cases. When I combine the explicit template instantiation and definition of serialize into one object for BaseObject and all DerivedObject, the linker keeps the registration information of the derived class (because MSVC uses object-level linking). Due to the coding standards in our institution this method was disapproved. Is there a way to make the linker keep the registration information of DerivedObject? Best regards, Markus Himmerich .h-File: ---------------------------------------- namespace boost{ namespace serialization { class access; } } class BaseObject { public: ... private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int /*version*/); } .cpp-File: ---------------------------------- #include <boost/archive/xml_iarchive.hpp> #include <boost/archive/xml_oarchive.hpp> #include <boost/serialization/export.hpp> #include <boost/serialization/utility.hpp> #include <boost/serialization/shared_ptr.hpp> #include <boost/serialization/vector.hpp> #include <boost/serialization/map.hpp> #include <boost/serialization/set.hpp> #include <boost/serialization/string.hpp> //Use precompiled headers for these headers template<class Archive> void BaseObject::serialize(Archive & ar, const unsigned int /*version*/) { ar & BOOST_SERIALIZATION_NVP(id_); ar & BOOST_SERIALIZATION_NVP(data1_); } template void a::serialize<>(boost::archive::xml_iarchive & ar, const unsigned int /*version*/); template void a::serialize<>(boost::archive::xml_oarchive & ar, const unsigned int /*version*/); BOOST_CLASS_EXPORT(a) BOOST_SERIALIZATION_SHARED_PTR(a) Analogous files for DerivedObject. </PRE> <meta content="text/html; charset=ISO-8859-1" Diese E-Mail und eventuell beigefügte Anhänge enthalten vertrauliche Informationen, die rechtlich besonders geschützt sein können, zum Beispiel durch das Bankgeheimnis. Diese Informationen sind ausschließlich für die als Adressaten genannten Personen bestimmt. Wenn Sie nicht der angeschriebene Empfänger sind oder diese E-Mail durch einen Übertragungsfehler erhalten haben, informieren Sie uns bitte sofort per E-Mail, Telefon oder Telefax und löschen danach die vorliegende E-Mail. Das unbefugte Kopieren dieser E-Mail, ihrer eventuell beigefügten Anhänge sowie die unbefugte Weitergabe der enthaltenen Informationen an Dritte sind nicht gestattet. Wir danken für Ihre Hilfe. This e-mail message together with its attachments, if any, is confidential and may contain information subject to legal privilege, e.g. banking secrecy. The information contained in this e-mail or its attachments is intended solely for the persons named as addressees. If you are not the intended recipient or have received this e-mail in error, please advise us immediately by e-mail, telephone or fax and delete this message. Any unauthorised copying of this message or unauthorised distribution of the information contained herein is prohibited. Thank you for your co-operation. <PRE>

2 1

Building boost with a non-default compiler?
by Dan Katz 10 Jul '08

10 Jul '08

Hi - I'm trying to build boost-1.35 on a Linux 2.4 machine where both gcc-2.95 (the default) and gcc-3.3 (the one I'd like to use) are installed, and I'm having a lot of problems. Perhaps you can help me figure out how to go forward? Attempt #1 -- use the configure script ======================================================================== To begin, I started by following the online instructions at http://www.boost.org/doc/libs/1_35_0/more/getting_started/unix-variants.html where it says (section 5.1) "Select your configuration options and invoke ./configure again...", so I selected the --with-toolset and --prefix options as follows: ------------------------------------ boost_1_35_0$ ./configure --with-toolset=gcc-3.3 --prefix=./BUILT Building Boost.Jam with toolset gcc-3.3... ./configure: ./bootstrap/jam0: No such file or directory tools/jam/src//bjam Detecting Python version... 2.2 Detecting Python root... /usr Unicode/ICU support for Boost.Regex?... not found. Generating Boost.Build configuration in user-config.jam... Generating Makefile... boost_1_35_0$ ------------------------------------ where I got the idea that the argument to --with-toolset should be gcc-3.3 from the description of toolsets in section 5.2.2 of the documentation which describes how to name toolsets for Boost.Build and states that If you have multiple versions of a particular compiler installed, you can append the version number to the toolset name, preceded by a hyphen, e.g. intel-9.0 or borland-5.4.3. Of course, trying to run the generated makefile fails miserably: ------------------------------------ boost_1_35_0$ make install ./tools/jam/src//bjam --user-config=user-config.jam --prefix=./BUILT --exec-prefix=./BUILT --libdir=./BUILT/lib --includedir=./BUILT/include install /bin/sh: ./tools/jam/src//bjam: No such file or directory Not all Boost libraries built properly. boost_1_35_0$ ------------------------------------ At this point I noticed that the documentation for section 5.2 states that "If you're using a compiler other than your system's default, you'll need to use Boost.Build to create binaries." Aha! Although it does leave me wondering what the --with-toolset option of the configure script is for... Attempt #2 -- Build Custom Binaries ======================================================================== For this attempt, I decided that I'd build everything from scratch. So I untarred a fresh source tree and began by building bjam, following the directions at http://www.boost.org/doc/libs/1_35_0/doc/html/jam/building.html ------------------------------------ $ cd tools/jam/src $ sh ./build.sh ------------------------------------ which build bjam cleanly using the gcc-2.95 default compiler. I then moved back to the root directory as described in section 5.2.4 of the documentation and invoked bjam as follows: ------------------------------------ $ export PATH=$BOOST_ROOT/tools/jam/src/bin.linuxx86:$PATH $ bjam --toolset=gcc-3.3 stage [...tons of stuff about compilation and failure messages...] ...failed updating 57 targets... ...skipped 52 targets... ...updated 188 targets... $ ------------------------------------ and while some of the libraries appear to have bee built, not all of them have been: ------------------------------------ $ find . -name libboost* ./stage/lib/libboost_signals-gcc33-mt-1_35.so ./stage/lib/libboost_regex-gcc33-mt.so ./stage/lib/libboost_regex-gcc33-mt-1_35.so ./stage/lib/libboost_prg_exec_monitor-gcc33-mt-1_35.so.1.35.0 ./stage/lib/libboost_prg_exec_monitor-gcc33-mt-1_35.so ./stage/lib/libboost_signals-gcc33-mt-1_35.so.1.35.0 ./stage/lib/libboost_signals-gcc33-mt.so ./stage/lib/libboost_prg_exec_monitor-gcc33-mt.so ./stage/lib/libboost_regex-gcc33-mt-1_35.so.1.35.0 ./bin.v2/libs/test/build/gcc-3.3/release/threading-multi/libboost_prg_exec_monitor-gcc33-mt-1_35.so.1.35.0 ./bin.v2/libs/regex/build/gcc-3.3/release/threading-multi/libboost_regex-gcc33-mt-1_35.so.1.35.0 ./bin.v2/libs/signals/build/gcc-3.3/release/threading-multi/libboost_signals-gcc33-mt-1_35.so.1.35.0 -------------------------------- which clearly shows that a wide variety of the libraries (such as boost_thread and boost_test) are missing. So the question is: do you have any suggestions about how I should proceed? I'm willing to capture all of the build output and look for failure messages to post here, but I thought I should show you what I did and see if there was anything glaringly wrong before I did that. Thanks! Dan

4 6

Boost logging in a dll
by Jon Shuler 10 Jul '08

10 Jul '08

I'm trying to use the boost logging in dll and I could not find any scenarios in the docs on what should be defined/declared in the dll and the exe. Has anyone tried this? Thanks, Jon

1 0

Asio sockets - non-blocking read
by Jean-Sebastien Stoezel 10 Jul '08

10 Jul '08

Hi, Is there a way to read from a synchronous TCP socket without blocking the calling thread? Like using a time out, or checking how many bytes are present on the socket before reading? Thanks, Jean

2 2

[date_time] Linking problem
by Dmitry Bufistov 10 Jul '08

10 Jul '08

Hi, I've attached a simple program with two .cpp files I failed to build on Debian 2.6 with boost 1.34.1/1.35.0 and g++ (GCC) 3.4.6 (Debian 3.4.6-5) with the following command line: dmitry@phoenix:$ echo $BOOST_INCLUDE /usr/usuaris/doctorat/dmitry/include/boost_1_35_0 dmitry@phoenix:$ g++ -I$BOOST_INCLUDE s1.cpp s2.cpp -O1 `.gnu.linkonce.t._ZN5boost9gregorian4dateC1ENS_9date_time14special_valuesE' referido en la secciСn `.rodata' de /tmp/ccgodEgX.o: se definiС en la secciСn descartada `.gnu.linkonce.t._ZN5boost9gregorian4dateC1ENS_9date_time14special_valuesE' de /tmp/ccgodEgX.o `.gnu.linkonce.t._ZN5boost9date_time19counted_time_systemINS0_16counted_time_repINS_10posix_time33millisec_posix_time_system_configEEEE14subtract_timesERKS5_S8_' referido en la secciСn `.rodata' de /tmp/ccgodEgX.o: se definiС en la secciСn descartada `.gnu.linkonce.t._ZN5boost9date_time19counted_time_systemINS0_16counted_time_repINS_10posix_time33millisec_posix_time_system_configEEEE14subtract_timesERKS5_S8_' de /tmp/ccgodEgX.o collect2: ld devolviС el estado de salida 1 dmitry@phoenix:$ Finally I've found that everything works fine with -O2 optimization, but just in case. What is wrong here? Regards, Dmitry

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