February 2009 - Boost-users - lists.preview.boost.org

Problem transforming a vector<bool> to a vector<any>
by Fabrice_CBA 04 Feb '09

04 Feb '09

Hi everyone, I am working on a project in which I'm using a "simplified" version of the boost::any library. By simplified, I mean that I got rid of the #defines and made it independent from the rest of boost. The changes are very small, and in my opinion shouldn't impact much the class, since the general structure is still there. My implementation is attached to this message. http://www.nabble.com/file/p21822878/Any.h Any.h However I am having a problem transferring a vector<bool> into a vector<any>. It works for any other types I've tested, only booleans fail. Here is an example: std::vector<std::string> source0(1, "SomeString"); std::vector<long> source1(1, 666); std::vector<bool> source2(1, true); std::vector<double> source3(1, 6.66); std::vector<any> destination; destination.push_back(source0[0]); destination.push_back(source1[0]); destination.push_back(source2[0]); destination.push_back(source3[0]); When checking what is in destination[2], it seems it only holds {...}, and not the original {true}. Whereas it works perfectly for the other values. Any idea on what I'm doing wrong? Any help appreciated. Thanks, Fabrice -- View this message in context: http://www.nabble.com/Problem-transforming-a-vector%3Cbool%3E-to-a-vector%3… Sent from the Boost - Users mailing list archive at Nabble.com.

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How to convert boost::posix_time::ptime to FILETIME structure?
by Archie14 03 Feb '09

03 Feb '09

Is there any helper function to convert boost::posix_time::ptime to FILETIME? I am trying to pass datetime value from boost-based app to another (C#). Looks like that FILETIME (that can be represented as long) is a good option, besides string. May be there is better alternative?

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Nullary metafunction
by er 03 Feb '09

03 Feb '09

Hi All, I'm looking for template<typename> class F such that F<T>::type is T::type if it exists, T itself otherwise. I was hoping apply<T>::type would work, by analogy with the well known example apply<std::vector<_>,X>::type, but apparently not.

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Thread locks
by Larry E. Ramey 03 Feb '09

03 Feb '09

Under 1.33.1 we used to do this: boost::try_mutex::scoped_try_lock lock(m_mutex); if (lock.locked() && m_threadState == UploadMap) { I'm not sure, but I think under 1.37 I should do: boost::try_mutex::scoped_try_lock lock(m_mutex); if (lock.owns_lock() && m_threadState == UploadMap) { When I do that, I get a crash when I exit that I never used to have. Any ideas? Larry

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[boost-users][lambda] crash in std::for_each
by Igor R 03 Feb '09

03 Feb '09

The following code crashes in for_each when trying to output the 1st pair. What's wrong with it? Thanks! namespace bl = boost::lambda; std::map<std::string, std::string> temp; temp["a"] = "1"; temp["b"] = "2"; const std::map<std::string, std::string> attrs(temp); typedef std::pair<std::string, std::string> string_pair; std::stringstream stream; std::for_each(attrs.begin(), attrs.end(), stream << bl::bind(&string_pair::first, bl::_1) << bl::bind(&string_pair::second, bl::_1));

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[asio] Cloning a WSA socket (windows)
by Tore Halvorsen 03 Feb '09

03 Feb '09

Hi, I am trying to clone a socket from process to another, mostly for having one process per client in a network server. Some legacy stuff makes this the only design possible, so the threaded approach is simply not feasible... Anyway, when I'm trying to create a boost socket from a cloned WSA socket I get an exception. class boost::exception_detail::clone_impl< struct boost::exception_detail::error_info_injector< class boost::system::system_error > > : The parameter is incorrect This same happens for this example program, using boost 1.37 Does anyone have an idea why this does not work? #ifndef _WIN32_WINNT #define _WIN32_WINNT 0x0501 #endif #define WIN32_LEAN_AND_MEAN #define NOMINMAX #include <windows.h> #include <winsock2.h> #pragma comment(lib, "ws2_32") #include <boost/asio.hpp> namespace ip = boost::asio::ip; int main_impl(int argc, char* argv[]) { boost::asio::io_service ios; ip::tcp::socket s(ios); ip::tcp::acceptor a(ios, ip::tcp::endpoint(ip::tcp::v4(), 1777)); a.accept(s); WSAPROTOCOL_INFO info; if (WSADuplicateSocket(s.native(), GetCurrentProcessId(), &info)) { std::cerr << "WSAError: " << WSAGetLastError() << std::endl; return EXIT_FAILURE; } // pass info over a pipe to the client... SOCKET copy(WSASocket(FROM_PROTOCOL_INFO, FROM_PROTOCOL_INFO , FROM_PROTOCOL_INFO, &info, NULL, NULL)); ip::tcp::socket scopy(ios, ip::tcp::v4(), copy); return EXIT_SUCCESS; } int main(int argc, char* argv[]) { try { return main_impl(argc, argv); } catch(std::exception const& ex) { std::cerr << typeid(ex).name() << ":" << ex.what() << std::endl; return EXIT_FAILURE; } } -- Eld på åren og sol på eng gjer mannen fegen og fjåg. [Jøtul] <demo> 2009 Tore Halvorsen || +052 0553034554

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[mpi] Non-default arguments for running regression tests through bjam
by Pete Bartlett 03 Feb '09

03 Feb '09

Dear Boosters, I am just going through the learning curve for Boost.MPI. My underlying target platform is MPICH2 on Windows XP/Vista. Given I am taking baby-steps I would like run the regression tests to check my install. Mpirun doesn't exist in my install - mpiexec is required instead. The docs and mpi.jam comments say "The (optional) fourth argument configures Boost.MPI for running regression tests. These parameters specify the executable used to launch jobs (default: "mpirun") followed by any necessary arguments to this to run tests and tell the program to expect the number of processors to follow (default: "-np")." I'm no jam expert, but that suggests that my user-config.jam should change to using mpi : : <find-shared-library>cxx <find-shared-library>mpi <library-path>C:/MPICH2/lib <include>C:/MPICH2/include : : mpiexec -n ; where the " : : mpiexec -n " is the new part. However this results in a slew of jam errors. I am able to run the regression tests by hacking mpi.jam to change the defaults, however I'd prefer to know the correct syntax in user-config.jam please. Thanks in advance for any help, Pete Bartlett

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Boost.lambda: can I do this with a lambda function (multiplestatements?
by Joost Kraaijeveld 03 Feb '09

03 Feb '09

Hi, I want to embed some debug printing in a lambda function which is a predicate used to remove elements from a vector like this: collection.erase( std::remove_if( collection.begin(), collection.end(), boost::lambda::if_then_else_return( boost::lambda::_1 <= "s5", // if (std::cout << "deleted: " << boost::lambda::_1, true), // then (std::cout << "not deleted: " << boost::lambda::_1, false ))), // else collection.end()); This actually compiles, runs and removes all the right elements but it does not print for every element it is checking. It just prints "not deleted: deleted: s4s5s6s8" , the last string being all the elements of the collection. Is what I want possible and if so how? TIA, -- Groeten, Joost Kraaijeveld Askesis B.V. Molukkenstraat 14 6524NB Nijmegen tel: 024-3888063 / 06-51855277 fax: 024-3608416 web: www.askesis.nl

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Boost:interprocess 1.36.0 - Minimum size for a shared memory segment
by Federico Golfrè Andreasi 03 Feb '09

03 Feb '09

Hi ! which is the minimum number of bytes I have to allocate to construct a managed shared memory? Or how can I calculate it? I did some tests and I believe is 112 bytes for 32 bit machines and 224 bytes for 64 bit, am I right ? And for the allocators? What I want to do is set the size of the shared memory smaller than I can, knowing the dimension of the variables I want to put in; even if the code is compiled in 64 bit or 32 bit machines. Thank you, Federico

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boost::tokenizer with char*
by Archie14 03 Feb '09

03 Feb '09

I was wandering if anyone can help me to understand how to use boost::tokenizer with char* buffer. tokenizer template parameters include string as default Type. I don't want to copy char* into string.

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