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

boost program options - notifier function 0 arguments
by Aljaz 08 Aug '08

08 Aug '08

Hello I've been wondering how its possible to call a notifier function with an option that doesnt require arguments. Something like: po::options_description desc("Allowed options"); desc.add_options() ("help", po::value<>()->notifier(&_help_function), "produce help message"); Whats the proper way of doing this? Many thanks in advance Aljaz

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too many arguments to function ‘boost::fusion::vector
by Peng Yu 08 Aug '08

08 Aug '08

Hi, I got the following error, when I try to define a boost::fusion::vector of many elements. Can somebody let me know how to increase the limit of the number of elements? Thanks, Peng /usr/include/boost/fusion/container/generation/make_vector.hpp|40| error: too many arguments to function 'boost::fusion::vector<boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_> boost::fusion::make_vector()'

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Re: [Boost-users] [boost-users] crash of visual studio compiler with boost bind
by Alan M. Carroll 08 Aug '08

08 Aug '08

Shouldn't that _2 be _1? Otherwise, isn't the third argument to the outer bind a binary functor? If so, could that syntax error be the cause of the crash? At 03:59 AM 8/7/2008, you wrote: >Hello, >the following code makes the VC++ compiler (VS 2005) crash, >but only when I am trying a release build ! The debug builds work fine. > >std::sort(l_vec.begin(),l_vec.end(),boost::bind(std::less<int>(),boost::bind(&CLayer::GetPrio,_1),boost::bind(&CLayer::GetPrio,_2)));

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[graph] Is there a way to detect circles in graphs using boost?
by Martin Mann 07 Aug '08

07 Aug '08

Hi, I would like to know if there is an easy/straight-forward way to get all circles of a graph using the boost::graph facilities? And if so where to look or how to do? Thanks a lot, Martin

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[Boost.thread] Simultaneously starting thread execution
by Ruediger Berlich 07 Aug '08

07 Aug '08

Hi there, I'm trying to find a way to let a number of threads start execution simultaneously, and in any case not before a certain condition has come true. I would also like to terminate them within a relatively short time frame. I can not use the Boost.Thread barrier class, as I do not know the number of threads in advance (users register consumer-type objects, and I do not know how many there will be). I also believe I do not have to use a condition variable, as the different threads need to synchronize their access to a data ressource anyway, and I can use the same mutex to block them in the beginning. I have thus come up with something like the code quoted below. Are there easier ways to do this with the Boost.Thread library ? One of the problems (which seems to be unrelated to the code below) is that the three threads do not get called equally often. In one run, one thread was called 14564 times, another 1607 times and the third one 8676 times. Thanks and Best Regards, Ruediger /***********************************************************************/ #include <iostream> #include <boost/cstdint.hpp> #include <boost/bind.hpp> #include <boost/thread/mutex.hpp> #include <boost/thread/condition.hpp> #include <boost/thread/condition_variable.hpp> #include <boost/thread/thread.hpp> using namespace std; class test { public: test() :lock(helloMutex_), jointData_(0), MAXJOINTDATA(10000), thread1(boost::bind(&test::sayHello, this)), thread2(boost::bind(&test::sayHello, this)), thread3(boost::bind(&test::sayHello, this)) { /* nothing */ } void startAndStopThreads(){ lock.unlock(); while(true){ boost::unique_lock<boost::mutex> local_lock(helloMutex_); if(jointData_ >= MAXJOINTDATA){ thread1.interrupt(); thread2.interrupt(); thread3.interrupt(); break; } } thread1.join(); thread2.join(); thread3.join(); } void sayHello(){ for(;;){ if(boost::this_thread::interruption_requested()) break; boost::unique_lock<boost::mutex> local_lock(helloMutex_); std::cout << "Hello world Nr. " << jointData_++ << " from thread " << boost::this_thread::get_id() << std::endl; } } private: boost::mutex helloMutex_; boost::unique_lock<boost::mutex> lock; uint32_t jointData_; const uint32_t MAXJOINTDATA; boost::thread thread1, thread2, thread3; }; main(){ test Test; Test.startAndStopThreads(); std::cout << "Done ..." << std::endl; }

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How to get the port number and the address of a boost::asio::ip::tcp:acceptor object
by Jean-Sebastien Stoezel 07 Aug '08

07 Aug '08

Hi, How to get the port number and ip address of an acceptor? I tried this: boost::asio::ip::tcp::acceptor acceptor(m_IoService); boost::asio::ip::tcp::acceptor myEndPoint(m_IoService); acceptor.get_option(myEndPoint); But this does not compile, Iget a couple of errors in win_iocp_socket_service.hpp like this one: Error 8 error C2039: 'level' : is not a member of 'boost::asio::basic_socket_acceptor<Protocol>' Thanks, Jean

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[filesystem] strange linker error
by Matthias Schabel 07 Aug '08

07 Aug '08

Using the 1.36 beta libs on OS X and linking to libboost_system- gcc40-1_36.a and libboost_filesystem-gcc40-1_36.a I get : "boost::system::error_code::message() const", referenced from: boost::system::system_error::what() constin main_mpi.o boost ::filesystem ::basic_filesystem_error <boost::filesystem::basic_path<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, boost::filesystem::path_traits> >::what() constin main_mpi.o ld: symbol(s) not found Any ideas what I'm doing wrong here? Matthias

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Re: [Boost-users] How to get the port number and the address of a boost::asio::ip::tcp:acceptor object
by Jean-Sebastien Stoezel 07 Aug '08

07 Aug '08

Hi, The following code: boost::asio::ip::tcp::acceptor myacceptor(m_IoService); myacceptor.open(boost::asio::ip::tcp::v4()); boost::asio::ip::tcp::endpoint endpoint = myacceptor.local_endpoint(); generates the following exception: "An invalid argument was supplied" when myacceptor.local_endpoint() is invoked. any idea? On 8/7/08, Igor R <boost.lists(a)gmail.com> wrote: > > Then when I do: > > > > boost::asio::ip::tcp::acceptor acceptor(m_IoService); > > > > when I call > > > > boost::asio::ip::tcp::endpoint endpoint = acceptor.local_endpoint(); > > > > I get an exception as follow: > > "The file handle supplied is not valid" > > You have to open() the acceptor: > http://www.boost.org/doc/libs/1_35_0/doc/html/boost_asio/reference/basic_so… >

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about UTF8 to UNICODE
by Ken zhang 07 Aug '08

07 Aug '08

Hello I hava a UTF8 string reading from TinyXML, I want convert to a Unicode string (wchar_t) for some reasons, How can convert it by boost? Thanks Kenneth.Sh

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[Multi-index] how to create 1-n relation between multi index containers?
by Prometheus Prometheus 07 Aug '08

07 Aug '08

hi all a few weeks ago i came across multi index and now im using it very intensively in my linux application (using g++) the problem im facing more often is a situation like this: i have a structure using multi index for server's (for example) typedef struct server{ uint32_t ip,port; std::string hostname; }; and i have a groups structure typedef struct servergroup{ std::string groupname; uint32_t groupid; time_t sometimestamp; uint32_t groupstate; // std::vector<server> members; // << could this be a multi_index? }; what i need to do is create a relation between a group and it's members (servers) and thats what im not sure about how to achive using multi_index the reason for the relationship is that i need to create an index for queries like this: In which group is server X? or Which servers has Group X? The only possibility i see is by creating 1 structure which causes much memory overhead and updating is a bit of a problem, cause i would need a loop for updating the state of the group for every member, ... I also thought about using boost bimap, but im pretty unsure how? So anybody has a hint on this (including maybe a very small example)? im pretty sure its some kind of 'not see the wood for trees' problem thx for ur time _________________________________________________________________ Discover the new Windows Vista http://search.msn.com/results.aspx?q=windows+vista&mkt=en-US&form=QBRE

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