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Importing namespaced templates
by Esben Mose Hansen 16 Feb '09

16 Feb '09

Hi, from the C++0x standard, 7.3.3 (5) I gather that it is not possible to write a using statement to import a templated function into the global namespace. E.g. #include <boost/units/quantity.hpp> using template<typename X, typename Y> boost::units::quantity_cast<X,Y>; will be malformed. The only alternatives I have been able to come up with are 1) Use boost::units::quantity_cast<X>(Y) which is a bit longwinded 2) Write a new quantity_cast in the global namespace, and forward it to the boost::units one. Is there a better way? (Sorry that this is only borderline a boost question) -- kind regards, Esben

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FindBoost.cmake
by Ruediger Berlich 16 Feb '09

16 Feb '09

Hi there, I'm using CMake as my build system -- not to build boost, but build my own project, which heavily depends on Boost. I habe in the past used the FindBoost.cmake macro to locate the most suitable Boost version. However, there does not seem to be a centrally maintained version of this file (I believe it originated from the KDE project ?), and I was wondering whether "anyone" in Boost was working on a replacement. After all, if CMake is considered as an alternative build system for Boost itself, allowing users to find the installed libraries would be the most logical step. Thanks and Best Regards, Ruediger

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Seeking writers to develop quarterly digests of Boost newsgroups
by Brian Wood 16 Feb '09

16 Feb '09

I'm planning to start an on line magazine called C++ Quarterly. *http://tinyurl.com/df6hn2 or **http://preview.tinyurl.com/df6hn2 * If you are interested in writing a quarterly digest of Boost Users and/or Boost Developers, please let me know. Alternatively, if you're interested in writing a non-digest article, I'd be happy to hear from you. Just to clarify something from the above link. I want to set things up so that advertisers send money directly to authors. Advertisers would send ads to us but money to authors. Brian Wood Ebenezer Enterprises www.webEbenezer.net <http://www.webebenezer.net/>

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[Regex]static compilation problems
by Moritz Beber 15 Feb '09

15 Feb '09

Dear users, to start using regular expressions I tried a very simple program only declaring one regular expression. #include <boost/regex.hpp> int main(int , char* []) { boost::regex re("\\d+"); return 0; } Linking and compiling this with the command: g++ test.cpp -o test -L ~/libs/boost/lib/ -l boost_regex-gcc43-mt works without problems, but running it then leads to the following: error while loading shared libraries: libboost_system-gcc43-mt-1_37.so.1.37.0: cannot open shared object file: No such file or directory But the directory clearly shows its existence: -rw-rw-r-- 1 engineer engineer 1587006 2008-11-21 07:53 /home/engineer/libs/boost/lib/libboost_regex-gcc43-mt-1_37.a lrwxrwxrwx 1 engineer engineer 38 2008-11-21 07:50 /home/engineer/libs/boost/lib/libboost_regex-gcc43-mt-1_37.so -> libboost_regex-gcc43-mt-1_37.so.1.37.0 -rwxrwxr-x 1 engineer engineer 722184 2008-11-21 07:50 /home/engineer/libs/boost/lib/libboost_regex-gcc43-mt-1_37.so.1.37.0 lrwxrwxrwx 1 engineer engineer 30 2008-11-21 07:53 /home/engineer/libs/boost/lib/libboost_regex-gcc43-mt.a -> libboost_regex-gcc43-mt-1_37.a lrwxrwxrwx 1 engineer engineer 38 2008-11-21 07:52 /home/engineer/libs/boost/lib/libboost_regex-gcc43-mt.so -> libboost_regex-gcc43-mt-1_37.so.1.37.0 Then I tried doing the same using static libraries: g++ -static test.cpp -o test -L ~/libs/boost/lib/ -l boost_regex-gcc43-mt but got an extremely long list of errors: /home/engineer/libs/boost/lib//libboost_regex-gcc43-mt.a(static_mutex.o): In function `boost::scoped_static_mutex_lock::unlock()': static_mutex.cpp:(.text+0x16): undefined reference to `pthread_mutex_unlock' /home/engineer/libs/boost/lib//libboost_regex-gcc43-mt.a(static_mutex.o): In function `boost::scoped_static_mutex_lock::lock()': static_mutex.cpp:(.text+0x46): undefined reference to `pthread_mutex_lock' /home/engineer/libs/boost/lib//libboost_regex-gcc43-mt.a(static_mutex.o): In function `boost::scoped_static_mutex_lock::~scoped_static_mutex_lock()': static_mutex.cpp:(.text+0x76): undefined reference to `pthread_mutex_unlock' /home/engineer/libs/boost/lib//libboost_regex-gcc43-mt.a(static_mutex.o): In function `boost::scoped_static_mutex_lock::~scoped_static_mutex_lock()': static_mutex.cpp:(.text+0xa6): undefined reference to `pthread_mutex_unlock' /home/engineer/libs/boost/lib//libboost_regex-gcc43-mt.a(static_mutex.o): In function `boost::scoped_static_mutex_lock::scoped_static_mutex_lock(boost::static_mutex&, bool)': static_mutex.cpp:(.text+0xdd): undefined reference to `pthread_mutex_lock' /home/engineer/libs/boost/lib//libboost_regex-gcc43-mt.a(static_mutex.o): In function `boost::scoped_static_mutex_lock::scoped_static_mutex_lock(boost::static_mutex&, bool)': static_mutex.cpp:(.text+0x10d): undefined reference to `pthread_mutex_lock' /usr/lib/gcc/i386-redhat-linux/4.3.0/libstdc++.a(locale.o): In function `__gnu_cxx::__scoped_lock::~__scoped_lock()': (.text._ZN9__gnu_cxx13__scoped_lockD1Ev[__gnu_cxx::__scoped_lock::~__scoped_lock()]+0x18): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i386-redhat-linux/4.3.0/libstdc++.a(locale.o): In function `std::locale::_Impl::_M_install_cache(std::locale::facet const*, unsigned int)': (.text._ZNSt6locale5_Impl16_M_install_cacheEPKNS_5facetEj+0x2d): undefined reference to `pthread_mutex_lock' /usr/lib/gcc/i386-redhat-linux/4.3.0/libstdc++.a(locale.o): In function `std::locale::_Impl::_M_install_cache(std::locale::facet const*, unsigned int)': (.text._ZNSt6locale5_Impl16_M_install_cacheEPKNS_5facetEj+0x59): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i386-redhat-linux/4.3.0/libstdc++.a(locale_init.o): In function `std::locale::locale()': (.text._ZNSt6localeC1Ev+0x2a): undefined reference to `pthread_mutex_lock' /usr/lib/gcc/i386-redhat-linux/4.3.0/libstdc++.a(locale_init.o): In function `std::locale::locale()': (.text._ZNSt6localeC1Ev+0x52): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i386-redhat-linux/4.3.0/libstdc++.a(locale_init.o): In function `std::locale::global(std::locale const&)': (.text._ZNSt6locale6globalERKS_+0x2a): undefined reference to `pthread_mutex_lock' /usr/lib/gcc/i386-redhat-linux/4.3.0/libstdc++.a(locale_init.o): In function `std::locale::global(std::locale const&)': (.text._ZNSt6locale6globalERKS_+0x9a): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i386-redhat-linux/4.3.0/libstdc++.a(locale_init.o): In function `std::locale::locale()': (.text._ZNSt6localeC2Ev+0x2a): undefined reference to `pthread_mutex_lock' /usr/lib/gcc/i386-redhat-linux/4.3.0/libstdc++.a(locale_init.o): In function `std::locale::locale()': (.text._ZNSt6localeC2Ev+0x52): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i386-redhat-linux/4.3.0/libstdc++.a(eh_alloc.o): In function `__cxa_free_exception': (.text.__cxa_free_exception+0x6b): undefined reference to `pthread_mutex_lock' /usr/lib/gcc/i386-redhat-linux/4.3.0/libstdc++.a(eh_alloc.o): In function `__cxa_free_exception': (.text.__cxa_free_exception+0x86): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i386-redhat-linux/4.3.0/libstdc++.a(eh_alloc.o): In function `__cxa_allocate_exception': (.text.__cxa_allocate_exception+0x6f): undefined reference to `pthread_mutex_lock' /usr/lib/gcc/i386-redhat-linux/4.3.0/libstdc++.a(eh_alloc.o): In function `__cxa_allocate_exception': (.text.__cxa_allocate_exception+0xd7): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i386-redhat-linux/4.3.0/libgcc_eh.a(unwind-dw2-fde-glibc.o): In function `__register_frame_info_bases': (.text+0x60): undefined reference to `pthread_mutex_lock' /usr/lib/gcc/i386-redhat-linux/4.3.0/libgcc_eh.a(unwind-dw2-fde-glibc.o): In function `__register_frame_info_bases': (.text+0x77): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i386-redhat-linux/4.3.0/libgcc_eh.a(unwind-dw2-fde-glibc.o): In function `__register_frame_info_table_bases': (.text+0x12a): undefined reference to `pthread_mutex_lock' /usr/lib/gcc/i386-redhat-linux/4.3.0/libgcc_eh.a(unwind-dw2-fde-glibc.o): In function `__register_frame_info_table_bases': (.text+0x141): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i386-redhat-linux/4.3.0/libgcc_eh.a(unwind-dw2-fde-glibc.o): In function `_Unwind_Find_FDE': (.text+0x18a8): undefined reference to `pthread_mutex_lock' /usr/lib/gcc/i386-redhat-linux/4.3.0/libgcc_eh.a(unwind-dw2-fde-glibc.o): In function `_Unwind_Find_FDE': (.text+0x18f8): undefined reference to `pthread_mutex_unlock' /usr/lib/gcc/i386-redhat-linux/4.3.0/libgcc_eh.a(unwind-dw2-fde-glibc.o): In function `__deregister_frame_info_bases': (.text+0x1aaa): undefined reference to `pthread_mutex_lock' /usr/lib/gcc/i386-redhat-linux/4.3.0/libgcc_eh.a(unwind-dw2-fde-glibc.o): In function `__deregister_frame_info_bases': (.text+0x1b2f): undefined reference to `pthread_mutex_unlock' collect2: ld returned 1 exit status If anyone could point me to a solution of this problem, or give one here I'd very much appreciate it. Thank you. Best, Moritz

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[Preprocessor] Questiona bout reentrant call and file iteration performance
by Joel Falcou 15 Feb '09

15 Feb '09

I've been playing with Boost PreProcessor for some times now and it really helped. Two corners still looks obscure for me as the doc doesn't provide clear-cut enough use-cases for my taste. 1/ Concerning the _D version of some macro, what's their use case ? I can see the example in the doc but I can't see why useing the normal version of the _D function should fail or behave badly 2/ Concerning file iteration vs BOOST_PP_REPEAT, what's the trade-off of one vs the other ? Is iterating faster at compile time than REPEATing ? Is there features of iteration that can't be done using REPEAT (or the reverse) or is the only bonus of ITERATE the fact that error actually send you in code and not on macro call site ? Thanks in advance -- ___________________________________________ Joel Falcou - Assistant Professor PARALL Team - LRI - Universite Paris Sud XI Tel : (+33)1 69 15 66 35

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boost interprocess / shared memory question
by Naveen Santhanam 14 Feb '09

14 Feb '09

Hello, We have a windows application (a process) that requires a large data file (approx. 100 MB) to perform a task. We have a master that launches several instances of this application. We would like to share the large data file across the processes such that, there is just one instance of the data file in physical memory without any disc access. Hence each application will have a small footprint in memory during execution. We have tried using a managed shared memory object from the boost::interprocess library to achieve this. However, this doesn't help us as the memory footprint of the application goes up upon access of the data file. Is there a way to achieve the desired single footprint memory sharing? Does this work as expected with other OSes? Naveen

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[fusion][mpl][array] making boost array a conforming mpl sequence (through fusion)
by Stjepan Rajko 14 Feb '09

14 Feb '09

Hi, I tried to make boost::array a conforming MPL sequence by including: #include <boost/fusion/adapted/array.hpp> // makes array a conforming fusion sequence #include <boost/fusion/mpl.hpp> // makes fusion sequences conforming MPL sequences but, typedef boost::array<int, 1> array; assert(boost::mpl::is_sequence<array>::type::value); // fails Am I misinterpreting the fusion documentation in expecting that this should work? Is there another way of making boost::array an mpl sequence? TIA, Stjepan

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Re: [Boost-users] [boost] [log][mpi]Review-ready version in the Vault
by jesseperla＠gmail.com 14 Feb '09

14 Feb '09

Hi guys, I am excited to use this library for logging. The design looks excellent. I am not competent enough to do a sanity check on the extensibility, but can anyone else see if the design would allow backends/attributes/etc. for MPE (maybe could be added to boost::MPI) Here is a simple tutorial: http://beige.ucs.indiana.edu/I590/node112.html -Jesse

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[boost-users][functiontypes]
by Germán Diago 14 Feb '09

14 Feb '09

Hello. I'm using boost.functiontypes and I would like if it's possible to extract information of arity and argument types from bind expressions and boost.functions. Thank you.

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[accumulator] Computing deviation
by dhruva 14 Feb '09

14 Feb '09

Hello, I would like to know if there is any direct way to compute standard deviation using accumulators or do I have to implement something using other building blocks from accumulators. -dhruva Add more friends to your messenger and enjoy! Go to http://messenger.yahoo.com/invite/

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