February 2010 - Boost-users - lists.preview.boost.org

Plugin library boost
by Lloyd 17 Feb '10

17 Feb '10

Hi, Does boost have a plug-in framework to develop a plug-in in applications. If not, does anybody know a good plug-in framework. Thank you very much, Lloyd ______________________________________ Scanned and protected by Email scanner

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random: uniform_01 usage and mixing boost::random with boost::math::normal
by Hicham Mouline 16 Feb '10

16 Feb '10

Hello, I have this code: boost::mt19937 mers; boost::uniform_01<boost::mt19937> uf01(mers); boost::exponential_distribution<> ed(0.1); I call the operator() on uf01 3 million times, as uf01() I don't quite understand the warning in the documentation about the constructor taking the generator by value. This means that my mers doesn't change between calls to uf01(). Is this bad? Will it affect the quality of the randomness of the uniform numbers generated? I also have boost::math::normal nrm; and I use boost::math::cdf(nrm, …) and boost::math::quantile( nrm, … ); Are there any issues with using both boost∷math∷normal and other distributions from the boost∷random library? Regards,

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[ASIO] When the work object is destroyed?
by Daniele Barzotti 16 Feb '10

16 Feb '10

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi, in my library I create a work object on the heap to maintain the io_service running and I assign it to a object member shared_ptr so, when the last object is destroyed, the work ends and the io_service.run() returns. All works but, if when I create an object after the thread is ended, the io_service returns immediately.. ..and I don't know why, any suggestions? Thanks! Daniele. - ------------------------------------------------------------------- // Main io_service static boost::asio::io_service io_service; static boost::scoped_ptr<boost::thread> io_service_thread; static boost::asio::io_service::work* p_work; static BOOL thread_started; void io_worker_thread(void) { #if(WIN32 && _WIN32_DCOM) struct com_init { com_init() { CoInitializeEx(NULL, COINIT_APARTMENTTHREADED); } ~com_init() { CoUninitialize(); } } initializer_object; #endif io_service.run(); thread_started = false; }; EXTERN_C EUROATLIB_API Hndl CALL GetTETRAMotoObj() { if (!thread_started) { try { // create the work object on the heap p_work = new boost::asio::io_service::work(io_service); // run the IO service as a separate thread: // Instead of start the worker thread directly by passing the // io_service object, // I call the io_worker_thread function where I can do some // initialization tasks like calling CoInitializeEx for COM io_service_thread.reset(new boost::thread(io_worker_thread)); thread_started = !thread_started; } catch (boost::thread_resource_error e) { // Failed to create the new thread return 0; } } // create the new object TETRAMoto* pTETRAMoto = new TETRAMoto(io_service); // Assign a reference to io_service work object: // This reference is used to counting the objects created. // When the last TETRAMoto object is deleted the main work object // is destroyed and the io_service thread ends. pTETRAMoto->_io_work_ptr.reset(p_work); // return the object return pTETRAMoto; }; - ------------------------------------------------------------------- -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (MingW32) iEYEARECAAYFAkt6f04ACgkQ/l+kMioSZwjYiwCgleSrLLiKKQlmZjN7HQBSEs75 olUAoKhMEV7/SK6tiI4hIxUoRjQv9qEE =KGSy -----END PGP SIGNATURE-----

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[Iostreams] stream<file_sink> does not throw an exception and not set fail/bad bits when file is wrong
by Mariusz Wojtysiak 16 Feb '10

16 Feb '10

Hello! I'm trying to write some content to a new file using boost::stream<file_sink> class. Unfortunately errors/failures during opening the file are ignored by boost library. Here is a snippet: using namespace boost::iostreams; stream<file_sink> stream( "/wrong.txt" ); std::cout << stream.fail() << ' ' << stream.bad() << std::endl; stream.exceptions( std::ios::badbit | std::ios::failbit ); stream << "test" << std::endl; stream.close(); Program is started as not root user and have not access for file / wrong.txt. It should throw an exception, but instead of this: - console prints: 0 0 - none exception is thrown - file /wrong.txt is not created Similar piece of code using std::ofstream works as I expect: using namespace std; ofstream stream( "/wrong.txt" ); std::cout << stream.fail() << ' ' << stream.bad() << std::endl; stream.exceptions( std::ios::badbit | std::ios::failbit ); stream << "test" << std::endl; stream.close(); - console prints: 1 0 - exception is thrown I cannot believe that boost::iostreams has such obvious bug and just ignore failures! I have to do something wrong. But what? Regards, Mariusz Wojtysiak

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how to realize that a connection is closed by a client
by Conoscenza Silente 16 Feb '10

16 Feb '10

Hi All I am doing first steps with boost::asio and I want to use ip::tcp::stream to send data from a server to a client. Reading the sample in boost docs I did a first sample of server code. Is there any way for the server to check if a client connection is closed or gone at some point? for( ;; ){ boost::asio::ip::tcp::iostream stream; acceptor.accept( *stream.rdbuf() ); for( int i = 0; i < 10; i++ ){ stream << "message" << i << std::endl; // how to realize that the client has gone here? boost::this_thread::sleep( boost::posix_time::milliseconds(1000) ); }

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Problems with boost build 1.42
by Avi Bahra 16 Feb '10

16 Feb '10

I am using bjam to build my application on suse linux. I have defined a environment variable BOOST_ROOT, which allows me to switch between boost builds. I have used this approach for 1.38, 1.39,1.40. I always build the boost libraries I need myself using bjam. bjam --build-dir=./tmpBuildDir toolset=gcc stage link=static --with-system i.e I don't bother with build scripts in $BOOST_ROOT With 1.42 when I build my application I get an error of the form: error: Unable to find file or target named error: '/var/tmp/ma0/boost/boost_1_42_0/stage/lib/libboost_system.a' error: referred from project at error: '' The error is very misleading because the file exists? When I switch back, to 1.39/1.40 there are no problems. This is what my boost-build.jam look like: -------------------------------------------------------------------------------- BOOST_BUILD = [ MATCH --boost-build=(.*) : $(ARGV) ] ; BOOST_BUILD ?= $(BOOST_ROOT)/tools/build/v2 ; boost-build $(BOOST_BUILD) ; Here is jam file for my leaf project: ---------------------------------------------------------------------------- use-project theCore : ../ACore ; exe test : [ glob src/*.cpp ] /site-config//boost_system /site-config//boost_serialization : <include>../SCRATCH/src <variant>debug:<define>DEBUG ; -------------------------------------------------------------------------- Notice that I reference /site-config// to reference the boost libs. for some reason in 1.42 this fails ! My site-config.file which is located in $BOOST_ROOT/tools/build/v2 is of the form: ------------------------------------------------------------------------ import os ; local BOOST_ROOT = [ os.environ BOOST_ROOT ] ; lib boost_serialization : : <file>$(BOOST_ROOT)/stage/lib/libboost_serialization.a ; lib boost_system : : <file>$(BOOST_ROOT)/stage/lib/libboost_system.a ; project site-config : requirements <include>$(BOOST_ROOT) ; using gcc ; using testing ; -------------------------------------------------------------------- My site-config.jam is the same between 1.40 and 1.42. There is probably a silly mistake on my part somewhere, but its preventing me from moving to 1.42. Any help appreciated. Best regards, Ta, Avi

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Server / client Boost.Test
by Christian Auby 16 Feb '10

16 Feb '10

How would I go about writing a unit test that runs first a network server, then connects to it and does some operations with it? I can see issues with the run order, and if there's a problem in the server it might never respond and the test would run forever. regards, Christian

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boost.asio Bus error on g++ 4.5 / Mac OS X 10.5.6
by Orca X 16 Feb '10

16 Feb '10

Hi! For some reason very simple program crashes with Bus error. code is --------------------------- #include <iostream> #include <boost/asio.hpp> int main(int argc, char **argv) { std::cout << "xxx" << std::endl; return 0; } --------------------------- Crash happens before any output is made. I'm using boost.build to build executables. The bug dissapears when building variant=debug. Gdb output: --------------------------- Program received signal EXC_BAD_ACCESS, Could not access memory. Reason: KERN_PROTECTION_FAILURE at address: 0x00000000 0x000019a8 in ?? () (gdb) bt #0 0x000019a8 in ?? () #1 0x00001e90 in boost::asio::detail::service_id<boost::asio::detail::reactive_descriptor_service<boost::asio::detail::kqueue_reactor<false> > >::~service_id () Previous frame inner to this frame (gdb could not unwind past this frame) --------------------------- Situation is that I'm building with g++4.5 installed from macports, with --std=c++0x, but boost itself was built with regular gcc 4.0.1. 4.5 version located at /opt/local/* , boost located at /usr/local/*. How could it happen that asio library destroys something even before my code is reached? No library initialization involved. Thanks in advance!

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Boost asio serial and rs-485
by Christian Auby 15 Feb '10

15 Feb '10

Is it possible to use Boost asio serial with rs485? If yes, is there anything special you need to be aware of? regards, Christian

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Trouble using bjam
by Roland Bock 15 Feb '10

15 Feb '10

Hi, I have a little trouble using bjam: I'd like to tell it to add /my/path to the include paths, by using this command-line: bjam include=/my/path I took this syntax from here: http://www.boost.org/boost-build2/doc/html/bbv2/overview/invocation.html#bb… But bjam answers with /usr/share/boost-build/build/property.jam:258: in validate1 from module property error: Invalid property '<include>': No value specified for feature 'include'. /usr/share/boost-build/build/property.jam:266: in property.validate from module property /usr/share/boost-build/build/build-request.jam:185: in convert-command-line-element from module build-request /usr/share/boost-build/build/build-request.jam:143: in build-request.from-command-line from module build-request /usr/share/boost-build/build-system.jam:164: in load from module build-system /usr/share/boost-build/kernel/modules.jam:261: in import from module modules /usr/share/boost-build/kernel/bootstrap.jam:132: in boost-build from module /usr/share/boost-build/boost-build.jam:1: in module scope from module Any idea? I am using bjam installed by Ubuntu-8.04: Boost.Build V2 (Milestone 11) Boost.Jam 03.1.14 Regards, Roland

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