March 2009 - Boost-users - lists.boost.org

range transformed -adaptor incompatible with lambda functions
by Sandeep Gupta 19 Mar '09

19 Mar '09

Hi, I would be nice if range-transformed worked with lambda functions. Is this an intended behaviour. To illustrate the following two statements fail for_each(myvec|boost::adaptors::transformed(arg1+mask), std::cout<<arg1<<' '); for_each(myvec|boost::adaptors::transformed(boost::lambda::_1 + mask), std::cout<<boost::lambda::_1<<' '); But this is fine: for_each(myvec|boost::adaptors::transformed(double_int()), std::cout<<boost::lambda::_1<<' '); where double_int hand created function object with result_type declaration. Thanks sandeep

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Re: [Boost-users] share_ptr reset() question
by 张亚霏 19 Mar '09

19 Mar '09

of cource, no memory leak. check out the source code of method 'reset'. there is a little trick help release the memory, which is similar with Effective STL: item 17: Use "swap trick" to trim excess capacity good luck ------------------ Original ------------------ From: "Ben"<befung(a)gmail.com>; Date: Thu, Mar 19, 2009 08:28 AM To: "boost-users"<boost-users(a)lists.boost.org>; Subject: [Boost-users] share_ptr reset() question Hello, Consider the following: void createSharePtr( boost::shared_ptr<int> value) { value.reset( new int(100)); } main() { boost::shared_ptr<int> y( new int(0)); createSharePtr( y); }; Question: Does the function createSharePtr() cause memory leak? Thanks, Ben _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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share_ptr reset() question
by Ben 19 Mar '09

19 Mar '09

Hello, Consider the following: void createSharePtr( boost::shared_ptr<int> value) { value.reset( new int(100)); } main() { boost::shared_ptr<int> y( new int(0)); createSharePtr( y); }; Question: Does the function createSharePtr() cause memory leak? Thanks, Ben

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Re: [Boost-users] [graph] Convert bidirectional graphs into directed graphs
by Juan Antonio Farré Basurte 19 Mar '09

19 Mar '09

>> I need to convert any bidirectional graph into an >> adjacency_list<vecS,vecS,directedS>, >> but looks like the copy constructor cannot handle it (needs the same type in input). >> I don't see any simple way to convert any directed graph into an adjacency_list<vecS,vecS,directedS>. >> Is there any more-or-less-simple way to do it that I don't know? May be there is a way to copy graphs constrained not by the concrete type of the graph, >> but only, may be, on graph concepts? >> Thanks, > > There's no direct conversion between *any* bidirectional graph and a directed adjancency_list. If you're talking about any bidirectional adjacency list and a directed one, you shouldn't actually need to convert them. > > As an alternative, you could use copy_graph. > I need to do a copy of the graph before writing it into graphml or graphviz as a workaround for the problem I reported with subject [graph] Looks like there is a bug in some graph-writing function , which in my second message with the same subject I clarified the problem was related with creating dynamic_properties from bundled properties. It doesn't work with const graphs and I don't trust just performing a const_cast. I want to make sure that the input graph to my graph-writing functions is not modified at all. One solution would be just to do Graph *copy=new Graph(graph); where Graph is the graph-type template parameter, but this would require Graph to model Assignable, and I don't want to impose that. Also, copying the graph into a directed (not bidirectional) adjacency_list will save memory. copy_graph is perfect for my needs, as graph-writing boost functions already require the graph to model VertexListGraph (and, in general, the code I'm developing too). Sorry for not remembering about copy_graph and thank you very much :) Juan

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Re: [Boost-users] Boost internal link problem
by Frank J. R. Hanstick 18 Mar '09

18 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 18 Mar '09

18 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 18 Mar '09

18 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 18 Mar '09

18 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 18 Mar '09

18 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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