September 2009 - Boost-users

link error on boost example using binary library
by N Z 15 Sep '09

15 Sep '09

Hi there, I am a beginner using boost. I am installing boost 1.40 on windows XP with sp3 and Visual Studio Standard 2008. I followed the "Getting Started on Windows" section 5.2 "Or, Simplified Build From Source. to build my binaries". i.e. bootstrap .\bjam I then tried to run the example in section 6:Link Your Program to a Boost Library. I got expected results when link from the IDE, however, I can't link under command prompt, here's the output I got when compiling: ****************************************************************************** C:\Documents and Settings\Administrator\My Documents\Visual Studio 2008\Projects\boostBinaryLibExamp>cl /EHsc /I "c:\Program Files\boost\boost_1_40_0" boostBinaryLibExamp\boostBinaryLibExamp.cpp /link "c:\Program Files\boost\boost_1_40_0\stage\lib\libboost_regex-vc90-mt-1_40.lib" Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 15.00.21022.08 for 80x86 Copyright (C) Microsoft Corporation. All rights reserved. boostBinaryLibExamp.cpp Microsoft (R) Incremental Linker Version 9.00.21022.08 Copyright (C) Microsoft Corporation. All rights reserved. /out:boostBinaryLibExamp.exe "c:\Program Files\boost\boost_1_40_0\stage\lib\libboost_regex-vc90-mt-1_40.lib" boostBinaryLibExamp.obj LINK : fatal error LNK1104: cannot open file 'libboost_regex-vc90-mt-s-1_40.lib' ****************************************************************************** I searched in the lib directory, there's no such file there. But why I can link from IDE but not in command prompt? btw, the boostPro installer only has version 1.39, right? I want to use 1.40. Thanks, Neil

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why is this bzip2 boost code so slow?
by ChristinaDRS 14 Sep '09

14 Sep '09

Hello, This code with bzip2 takes 185 seconds to do 10000 iterations of compressing and uncompressing. This seems way too high. When I replace the bzip2 code with zlib code it take roughly 7 seconds. Anyone know what might be wrong? #include <iostream> #include <sstream> #include <boost/assign/list_of.hpp> #include <boost/date_time/posix_time/posix_time.hpp> #include <boost/foreach.hpp> #include <boost/format.hpp> #include <boost/lexical_cast.hpp> #include <boost/numeric/conversion/cast.hpp> #include <boost/iostreams/copy.hpp> #include <boost/iostreams/device/back_inserter.hpp> #include <boost/iostreams/filter/bzip2.hpp> #include <boost/iostreams/filter/zlib.hpp> #include <boost/iostreams/filtering_stream.hpp> using namespace std; typedef boost::posix_time::ptime TimeType; TimeType current_time() { return boost::posix_time::microsec_clock::local_time(); } double elapsed_seconds(const TimeType& start_time) { static const double MSEC_PER_SEC = 1000.0; TimeType end_time = current_time(); boost::posix_time::time_duration elapsed = end_time - start_time; return boost::numeric_cast<double>(elapsed.total_milliseconds()) / MSEC_PER_SEC; } string decompress(const string& data) { boost::iostreams::filtering_streambuf<boost::iostreams::input> in; in.push(boost::iostreams::bzip2_decompressor()); in.push(boost::make_iterator_range(data)); string decompressed; boost::iostreams::copy(in, boost::iostreams::back_inserter(decompressed)); return decompressed; } int main() { TimeType start_time = current_time(); string compressed, received_data; boost::iostreams::filtering_streambuf<boost::iostreams::output> out, in; const string send_data = "boo! how are you?"; for(int i = 0; i < 10000; ++i) { //compress out.push(boost::iostreams::bzip2_compressor()); out.push(boost::iostreams::back_inserter(compressed)); boost::iostreams::copy(boost::make_iterator_range(send_data), out); const string compressed1=compressed; //decompress received_data = decompress(compressed); } cout << "time elapsed: " << elapsed_seconds(start_time) << endl; } -- View this message in context: http://www.nabble.com/why-is-this-bzip2-boost-code-so-slow--tp25442062p2544… Sent from the Boost - Users mailing list archive at Nabble.com.

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[spirit] benchmarks/qi benchmarks valid?
by Daniel Mierswa 14 Sep '09

14 Sep '09

Hey list, I was merely wondering if what I'm doing is right or if I fail at basic benchmarking: impulze@istari ~/dev/repositories/boost.svn/libs/spirit/benchmarks/qi $ g++ -O3 int_parser.cpp -I../../../../ -lrt && ./a.out /////////////////////////////////////////////////////////////////////////// Numbers to test: 1 digit number:-5 2 digit number:-54 3 digit number:541 4 digit number:-9604 5 digit number:-50733 6 digit number:-162974 7 digit number:-3133813 8 digit number:39950230 9 digit number:298344332 /////////////////////////////////////////////////////////////////////////// atoi_test: 5.0041852930 [s] {checksum: 13f6bf40} strtol_test: 5.4193627260 [s] {checksum: 13f6bf40} spirit_int_test: 2.2137115780 [s] {checksum: 13f6bf40} impulze@istari ~/dev/repositories/boost.svn/libs/spirit/benchmarks/qi $ g++ -O0 int_parser.cpp -I../../../../ -lrt && ./a.out /////////////////////////////////////////////////////////////////////////// Numbers to test: 1 digit number:5 2 digit number:-55 3 digit number:-978 4 digit number:2835 5 digit number:-78343 6 digit number:354806 7 digit number:9413631 8 digit number:-10824620 9 digit number:-369204759 /////////////////////////////////////////////////////////////////////////// atoi_test: 0.5902040060 [s] {checksum: e9ed193a} strtol_test: 0.6001010490 [s] {checksum: e9ed193a} spirit_int_test: 3.6562933090 [s] {checksum: e9ed193a} According to this, the optimized binary is 10 times slower wrt to the atoi/strtol implementation. I find that somehow quite hard to believe, is my toolchain broken, the testsuite or is it really true? The level of optimization doesn't matter btw, I get similar results with -O[,1,2] Any ideas are welcome. -- Mierswa, Daniel If you still don't like it, that's ok: that's why I'm boss. I simply know better than you do. --- Linus Torvalds, comp.os.linux.advocacy, 1996/07/22

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Boost.Signals2 - tracking an object managed with tr1::shared_ptr
by Monteleone, Nathan 14 Sep '09

14 Sep '09

Is it possible to use slot::track with a tr1::shared_ptr instead of a boost::shared_ptr? For example: std::tr1::shared_ptr<MyObject> o; typedef boost::signals2::signal<void(void)> SigType; SigType s; // Error: can't convert std::tr1::shared_ptr<MyObject> to boost::weak_ptr... s.connect(SigType::slot_type(&MyObject::function, o.get()).track(o)); According to the docs you HAVE to use boost::shared_ptr. I'm just hoping there's some traits specialization or something I can provide so that I can get away with using the tr1 version instead (all our code is already written with tr1). Thanks! -Nathan

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lexical problem
by pedro chaparro 14 Sep '09

14 Sep '09

hi, i'm working over a code to interchange messages using sockets, i have a server that when client connect to, server sends a char number(eg "100"), when client receives this string number, it has to addition +5 , to do that i need to change format from string to int and make sum operation, but when i do de change of format i get some error this message on the console window : bad lexical cast : source type value could not be interpreted as target Part of the code is : boost::array<char, 2> buf; boost::system::error_code error; size_t len = socket.read_some(boost::asio::buffer(buf), error); if (error == boost::asio::error::eof) break; // Connection closed cleanly by peer. std::string datos=buf.data(); int rxint; vector[2]=buf.data(); *rxint=boost::lexical_cast<int>(datos);* //(here is the problem) std::cout.write(buf.data(), len); do i making something wrong? -- Ing Pedro Alonso Chaparro Valero Ciudad Politecnica de la Innovación iTEAM - Mobile Communications Group Polytechnic University of Valencia C\ Camino de Vera S/N, Edificio 8G 46022 Valencia, Spain

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[Filesystem] Problem with uncatchable exception when checking empty card reader
by Marco Wedekind 14 Sep '09

14 Sep '09

Hello, I am using the Filesystem library from boost 1.38.0 on Windows (Visual Studio 2005) like this: if (boost::filesystem::exists("W:") && boost::filesystem::is_empty("W:")) { ... do something useful ... } "W:" is assigned to an (usually) empty card reader slot. Unfortunately Filesystem's exists() function fails with an uncatchable exception. At least I cannot catch it... The exception is thrown by GetFileAttributesA() in operations.hpp: inline DWORD get_file_attributes( const char * ph ) { return ::GetFileAttributesA( ph ); } The exception pops up an error message that is titled "Windows - no disc" and it says: Exception Processing Message c0000013 Parameters 75b0bf9c 4 75b0bf9c 75b0bf9c Sadly, all I can do is to prefix a call to exists() with a call to GetVolumeInformationA() (from winbase.h) like this: if (GetVolumeInformationA("W:", NULL, NULL, NULL, NULL, NULL, NULL, NULL)) { if (boost::filesystem::exists("W:") && boost::filesystem::is_empty("W:")) { ... do something useful ... } } Is there any way to do this platform-independent? I have been searching the docs and the boost website, google and so on, to see if that can already be done with boost Filesystem. Since I did not find anything on this topic, I hope you can put me on the right track. Cheers, Marco Marco Wedekind | Software Developer | marco.wedekind(a)tomtom.com | +49(0)34124495-62 office | +49(0)34124495-25 fax TomTom Development Germany GmbH, Maximilianallee 4, D-04129 Leipzig, Germany | www.tomtomwork.com Amtsgericht Leipzig | HRB 22234 | Geschäftsführer: Thomas Schmidt, Marina Wyatt  Think before you print This e-mail message contains information which is confidential and may be privileged. It is intended for use by the addressee only. If you are not the intended addressee, we request that you notify the sender immediately and delete or destroy this e-mail message and any attachment(s), without copying, saving, forwarding, disclosing or using its contents in any other way. TomTom N.V., TomTom Software, Ltd or any other company belonging to the TomTom group of companies will not be liable for damage relating to the communication by e-mail of data, documents or any other information. This e-mail message contains information which is confidential and may be privileged. It is intended for use by the addressee only. If you are not the intended addressee, we request that you notify the sender immediately and delete or destroy this e-mail message and any attachment(s), without copying, saving, forwarding, disclosing or using its contents in any other way. TomTom N.V., TomTom Software, Ltd or any other company belonging to the TomTom group of companies will not be liable for damage relating to the communication by e-mail of data, documents or any other information.

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[ptr_container] Dereferencing boost::signals2::signal from ptr_map
by Philipp Gildein 14 Sep '09

14 Sep '09

Hi, I got a huge problem with a boost::ptr_map. I am storing instances of boost::signals2::signal in it and try to dereference a iterator to one of those instances, to be able to call the operator () of the signal. This compiles correctly on Linux and gcc 4.4 but fails on Windows using Visual C++ 2008. The ptr_map is of type: typedef boost::ptr_map <std::string, boost::signals2::signal <void (Event)> > EventMap; And what i am trying to do is this: EventMap::iterator it = mEvents.find (event); if (it == mEvents.end ()) EXCEPTION ("Event doesn't exist"); (*it->second) (evt); The error message on Windows: C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\include \xutility(419) : error C2664: 'boost::signals2::detail::stack_allocator<T,n_stack_elements>::stack_allocator(boost::signals2::detail::stack_storage<T,10> *)': Konvertierung des Parameters 1 von 'boost::signals2::detail::stack_allocator<T,n_stack_elements>' in 'boost::signals2::detail::stack_storage<T,n_stack_elements> *' nicht möglich with [ T=std::_Aux_cont, n_stack_elements=10 ] and [ T=boost::shared_ptr<void>, n_stack_elements=10 ] and [ T=std::_Aux_cont, n_stack_elements=10 ] (First line translated is: Conversion of the first parameter from ... to .. not possible). For the complete code see http://github.com/rmbl/openspeak/raw/487dfcbea24df79216171f37d3102f8e76c8f7… and http://github.com/rmbl/openspeak/raw/487dfcbea24df79216171f37d3102f8e76c8f7… Thanks for any help. Regards Philipp Gildein

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[program_options] simple test case fails
by Christian Henning 14 Sep '09

14 Sep '09

Hi there, I'm working against the trunk but the following program doesn't run properly. #include <iostream> #include <boost/program_options.hpp> using namespace std; namespace po = boost::program_options; int main(int argc, char* argv[]) { string input; po::options_description desc("Allowed options"); desc.add_options() ( "help,h" , "produce help message" ) ( "input,i" , po::value<string>( &input ), "Input File" ); po::variables_map vm; po::store( po::parse_command_line(argc, argv, desc), vm ); po::notify( vm ); if( vm.count( "help" )) { cout << desc << endl; return 1; } } When calling po::store() I get an assertion saying: "Expression: map/set iterators incompatible". My command line parameter is "--help". I'm using autolink and MSVC 2005. Regards, Christian

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Building Boost 1.40
by Andrew Maclean 14 Sep '09

14 Sep '09

I built Boost 1.40 on Linux and installed it Ok. However are the libraries singlethreaded or multithreaded? eg. the library names are like this: libboost_python.so libboost_python.so.1.40.0 The older versions had -mt- in their name. eg. libboost_python-gcc43-mt.so etc. Thanks Andrew -- ___________________________________________ Andrew J. P. Maclean Centre for Autonomous Systems The Rose Street Building J04 The University of Sydney 2006 NSW AUSTRALIA Ph: +61 2 9351 3283 Fax: +61 2 9351 7474 URL: http://www.acfr.usyd.edu.au/ ___________________________________________

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[interprocess] named_condition.timed_wait does not wait.
by Moritz 14 Sep '09

14 Sep '09

Hi all, I am fighting with the named_condition again. Currently I am using timed_wait but it does not behave like I expected. Sometimes it is okay (triggers on the given timeout) but sometimes it just returns immediately false (ignoring the timeout). Can someone give me a hint what I am doing wrong? Thanks in advance. Here is a simplified version of what I try to do: using namespace boost::interprocess; using namespace boost::posix_time; _process1_: (WRITER) scoped_lock<named_mutex> lock(mtx1); write_sth_to_shared_memory(); flag = true; named_condition1.notify_all(); named_condition2.wait(lock); _process2_: (READER) scoped_lock<named_mutex> lock(mtx2); while (true) { while (!flag) { flag = check_flag(); // set up timeout time_duration delay(milliseconds(200)); ptime timeout = ptime(second_clock::universal_time()); timeout += delay; // wait if (named_condition1.timed_wait(lock)) { check_for_interrupt(); break; } else { check_for_interrupt(); continue; } } do_some_reading_from_shared_mem(); named_condition2.notify(all); }

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