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Re: [Boost-users] Boost internal link problem
by Frank J. R. Hanstick 19 Mar '09

19 Mar '09

Frank J. R. Hanstick wrote: > /bin/sh ../libtool --tag=CXX --mode=link g++ -D_THREAD_SAFE -g -O2 > -lboost_system-xgcc40-mt-1_37.dylib -o browser browser.o > libtest-openvrml.la -lboost_unit_test_framework-xgcc40-mt-1_37 > -lboost_filesystem-xgcc40-mt-1_37 > /usr/bin/ld: can't locate file for: -lboost_system-xgcc40- mt-1_37.dylib Shouldn't this be -lboost_system-xgcc40-mt-1_37 (no .dylib) Also, why is it in a different place from the other libs? In Christ, Steven Watanabe >> /usr/bin/ld: can't locate file for: -lboost_system-xgcc40- mt-1_37.dylib >Shouldn't this be -lboost_system-xgcc40-mt-1_37 (no .dylib) There is not an -lboost_system-xgcc40-mt-1_37 input to g++ when this occurs, so, it had to be gotten from somewhere else, either internal to g++ which is unlikely or from libboost_filesystem_xgcc40-mt-1_37. >Also, why is it in a different place from the other libs? All Boost libraries are in /usr/local/lib where they are suppose to be. This is verified by the command: make check LDFLAGS='-lboost_system-xgcc40-mt-1_37' successfully finding libboost_system-xgcc-mt-1_37.dylib. Come think of it, there is also a libboost_xxx-xgcc40-mt set of Boost libraries from an earlier install that gave the exact same error message when libboost_system_xgcc40-mt is not specified which would indicate that somewhere within libboost_filesystem_xgcc40-mt and libboost_filesystem_xgcc40-mt-1_37 is an improper link direction generated by the Boost library build that is overridden by the LDFLAGS input. Frank J. R. Hanstick trog24(a)comcast.net

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Boost internal link problem
by Frank J. R. Hanstick 19 Mar '09

19 Mar '09

Hello, Trying to link to the Boost libraries for openvrml resulted in the following error: /bin/sh ../libtool --tag=CXX --mode=link g++ -D_THREAD_SAFE -g - O2 -lboost_system-xgcc40-mt-1_37.dylib -o browser browser.o libtest- openvrml.la -lboost_unit_test_framework-xgcc40-mt-1_37 - lboost_filesystem-xgcc40-mt-1_37 g++ -D_THREAD_SAFE -g -O2 -o .libs/browser browser.o -Wl,- bind_at_load -lboost_system-xgcc40-mt-1_37.dylib ./.libs/libtest- openvrml.a -L/usr/local/lib -L/opt/local/lib /Users/frank/ FirefoxDownloads/openvrml-0.17.12/src/libopenvrml/.libs/ libopenvrml.dylib -L/opt/local/lib/firefox-2.0.0.20 /opt/local/lib/ libjpeg.dylib /opt/local/lib/libpng12.dylib /opt/local/lib/ libfontconfig.dylib /opt/local/lib/libiconv.dylib /opt/local/lib/ libexpat.dylib /opt/local/lib/libfreetype.dylib -lz -lmozjs -lplds4 - lplc4 -lnspr4 -lboost_thread-xgcc40-mt-1_37 - lboost_unit_test_framework-xgcc40-mt-1_37 -lboost_filesystem-xgcc40- mt-1_37 /usr/bin/ld: can't locate file for: -lboost_system-xgcc40-mt-1_37.dylib collect2: ld returned 1 exit status make[2]: *** [browser] Error 1 make[2]: Leaving directory `/Users/frank/FirefoxDownloads/ openvrml-0.17.12/tests' make[1]: *** [check-am] Error 2 make[1]: Leaving directory `/Users/frank/FirefoxDownloads/ openvrml-0.17.12/tests' make: *** [check-recursive] Error 1 The command sequence that led to the error was: ./configure BOOST_LIB_SUFFIX="-xgcc40-mt-1_37" LDFLAGS="-L/usr/local/ lib -L/opt/local/lib" CPPFLAGS=-I"/usr/local/spidermonkey/include/ -I/ Users/frank/FirefoxDownloads/xulrunner-sdk/sdk/include/ -DXP_UNIX" PKG_CONFIG_PATH="/opt/local/lib/pkgconfig/:/usr/local/lib/pkgconfig:/ sw/lib/pkgconfig" --with-libjs make make check A work around to the error was: make check LDFLAGS='-lboost_system-xgcc40-mt-1_37' The question is why the additional -l was needed to link two Boost libraries in order to overcome a dependency between the two Boost libraries. Frank J. R. Hanstick trog24(a)comcast.net

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pointer to member function of multi_index
by Sandeep Gupta 19 Mar '09

19 Mar '09

Hi, I am sure this is due to some trivial mistake; the statement to create a pointer member function insert of multi_index container fails in the following code: typedef multi_index_container< std::pair<int,int>, indexed_by< ordered_unique<member<pair<int,int>, int, &pair<int, int>::first> > > > mic; std::pair<mic_index::iterator, bool> (mic_index::*fn)(pair<int,int>) = &mic_index::insert; //compile error The error is due to mismatch in signature as given in the error: std::pair<boost::multi_index::detail::bidir_node_iterator<boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::index_node_base<std::pair<int, int>, ... std::pair<boost::multi_index::detail::bidir_node_iterator<boost::multi_index::detail::ordered_index_node<typename SuperMeta::type::node_type> >, bool>... If need be I can post full error message. Appreciate any suggestions. Thanks sandeep

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[boost-thread] error in the docs???
by Ovanes Markarian 19 Mar '09

19 Mar '09

Hello *, I think there is an error in the docs at: http://www.boost.org/doc/libs/1_38_0/doc/html/thread/synchronization.html#t… Member Function of condition_variable class is documented as: template<typename predicate_type> void wait(boost::unique_lock<boost::mutex>& lock, predicate_type pred) Effects: As-if while(!pred()) { wait(lock); } Should be: template<typename predicate_type> void wait(boost::unique_lock<boost::mutex>& lock, predicate_type pred) Effects: As-if while(pred()) //!!!!! no not operator { wait(lock); } If I pass the negated predicate to the wait, my thread blocks forever, whereas passing the predicate works as intended. This applies to the version 1.36, but 1.38 states the same in the docs. Thanks, Ovanes

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Re: [Boost-users] [boost_signals] How can i accelerate the compile process under VC.net?
by boost michael 19 Mar '09

19 Mar '09

Hi all, I'm a newbie of boost. I use boost signals mechanism in my project which is developed in VC.net 2003. The boost libs(ver 1_34_1) have already been installed and built correctly. But i still find that the compile precess of each file of my project will become quite slow if a boost function call is included. The total time spending on the compilation of my project may exceed 20 minutes. And I think that is quite long if compared with the compilation of a project with pure funcitons of VC libs. Can anyone give me any advice on how to accelerate the compilation? Thanks ahead. Best, Michael H.

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reference to ‘_1’ is ambiguous
by Sandeep Gupta 18 Mar '09

18 Mar '09

Hi, This problem has appeared before on the list but in a different context. The following code std::vector<int> myvec; for_each(myvec, std::cout<<_1<<' '); gives the error: Serializer.h:78: error: reference to ‘_1’ is ambiguous /home/sandeep/Computing/boost_1_38_0/boost/lambda/core.hpp:69: error: candidates are: const boost::lambda::placeholder1_type& boost::lambda::<unnamed>::_1 /home/sandeep/Computing/boost_1_38_0/boost/bind/placeholders.hpp:54: error: boost::arg<1> <unnamed>::_1 Serializer.h:78: error: reference to ‘_1’ is ambiguous I believe boost/bind is getting included indirectly via some other library. I have tried several modification but none seem to work as I was quite reluctant to post a third mail on the list. Thanks, sandep

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Problem with 'cannot instantiate abstract class' after switching from BOOST 1.33.0 to 1.34.1 (also VS2005 -> VS2008)
by Tobias Alte 18 Mar '09

18 Mar '09

Hi everyone, After switching from BOOST 1.33.0 to 1.34.1 (and also from VS2005 -> VS2008) we got a couple of problems with "cannot instantiate abstract class" errors. The application compiles fine in the setup VS2005 + BOOST 1.33.0 but suddenly started to throw a couple of "cannot instantiate abstract class" errors when using VS2008 + BOOST 1.34.1 . The errors itself get reported for 'concept_check.hpp' but that header did not change between the two BOOST releases (as far as I know - I think I made a diff with no results). I believe that the issue is most likely related to the boost::shared_ptr's to templated classes in our code. I already solved a few of these errors that arose thanks to slightly different types in the method definitions thanks to VS2008 having more built in types. However, the current "cannot instantiate abstract class" errors are persistently eluding my grasp. And the compiler is not helpful with just reporting the error in 'concept_check.hpp' and not where it really is. Questions: Can anyone of you think of additional (compiler) switches for BOOST (or even VS2008) that could help track down these kind of the issues? Did anyone experience similar problems when switching between BOOST versions (in general)? Thanks a lot for reading this and for any advice. T

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Passing arguments to threads
by r ottmanj 18 Mar '09

18 Mar '09

I am working on an application that takes use of boost::thread. During the initial method of my application I need to pass one argument to the method. As per the api documentation for boost::thread I am using the following: boost::thread dataThread(dparse.dataMain,instUUID); dataThread.join(); However, when I attempt to use this, I get the following exception from my compiler. Is there something that I am missing? I do not see how my thread constructor is any different from the constructor in the api documentation. Any help with this is greatly appreciated. error: no matching function for call to ‘boost::thread::thread(<unresolved overloaded function type>, std::string&)’ /usr/include/boost/thread/thread.hpp:38: note: candidates are: boost::thread::thread(const boost::function0<void, std::allocator<boost::function_base> >&) /usr/include/boost/thread/thread.hpp:37: note: boost::thread::thread() /usr/include/boost/thread/thread.hpp:35: note: boost::thread::thread(const boost::thread&)

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[Lexical Cast] Strange behaviour
by Robert Jones 18 Mar '09

18 Mar '09

I know this is not new, but I've just bumped into it.... This code #include <iostream> #include <boost/lexical_cast.hpp> int main(int argc, char* argv[]) { try { ulong u = boost::lexical_cast<ulong>("-1"); cout<<"Conversion"< } catch(const std::exception&) { cout<<"Exception"< } } Silently returns ULONG_MAX under MSVC7, though not under GCC. It's an accuate reflection of how the underlying C library handles it, but do we want to propogate this strangeness? Rob.

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[asio] io_service threadpool performance
by Rutger ter Borg 18 Mar '09

18 Mar '09

Dear all, I have been testing asio's io_service in a threadpool setup for job dispatching. However, it seems as if adding threads doesn't improve performance; perhaps even the opposite with 1 thread having the best performance. See below for some results of a simple test I'm doing, posting 10 M jobs to the io_service, and starting N threads at io_service::run after that. Timings below are measured on an 8-core machine, I would expect the execution performance to improve (not to get worse) for execution by more threads. Posting to the io_service is done single-threaded, so these timings should remain approx. the same. Please find attached the test program. Is there something I've missed and/or should tweak to get the desired improvement per added thread? Many thanks, Kind regards, Rutger ter Borg Concurrency = 1 Finished posting after: 3.15 Finished execution after: 5.44 Execs / sec: 1e+07/2.29=4.36681e+06 Concurrency = 2 Finished posting after: 2.85 Finished execution after: 5.47 Execs / sec: 1e+07/2.62=3.81679e+06 Concurrency = 3 Finished posting after: 3.15 Finished execution after: 11.65 Execs / sec: 1e+07/8.5=1.17647e+06 Concurrency = 4 Finished posting after: 3.15 Finished execution after: 9.8 Execs / sec: 1e+07/6.65=1.50376e+06 Concurrency = 5 Finished posting after: 3.28 Finished execution after: 12.45 Execs / sec: 1e+07/9.17=1.09051e+06 Concurrency = 6 Finished posting after: 3.29 Finished execution after: 8.84 Execs / sec: 1e+07/5.55=1.8018e+06 Concurrency = 7 Finished posting after: 3.51 Finished execution after: 10.09 Execs / sec: 1e+07/6.58=1.51976e+06 Concurrency = 8 Finished posting after: 3.38 Finished execution after: 12.54 Execs / sec: 1e+07/9.16=1.0917e+06

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