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

Re: [Boost-users] thread_group::interrupt_all is not reliable
by Stonewall Ballard 08 Dec '09

08 Dec '09

I think I found the cause of this problem. It seems that the caller of interrupt_all should be holding the mutex associated with the condition on which the threads are waiting. This gave me the clue to try that: <http://www.opengroup.org/onlinepubs/009695399/functions/pthread_cond_broadc…> > The pthread_cond_broadcast() or pthread_cond_signal() functions may be called by a thread whether or not it currently owns the mutex that threads calling pthread_cond_wait() or pthread_cond_timedwait() have associated with the condition variable during their waits; however, if predictable scheduling behavior is required, then that mutex shall be locked by the thread calling pthread_cond_broadcast() or pthread_cond_signal(). thread::interrupt() calls pthread_cond_broadcast in pthread/thread.cpp. Although "predictable scheduling" doesn't seem like it should include a failure to wake up, taking the mutex around the call to thread_pool::interrupt_all() appears to be 100% reliable. I can patch my app to do that, but I don't think there's a general solution. The documentation should include a note that thread::interrupt() isn't reliable unless the caller is holding the mutex associated with the condition variable on which the interrupted thread is waiting. Of course, this could be a bug in the OS X pthreads implementation as well. - Stoney > I've discovered that under circumstances apparently related to timing > and load, sending interrupt_all to a thread_group when all the threads > are waiting on a boost::condition_variable leaves one thread waiting > about 1/3 of the time. This is with boost 1_40_0 running on Mac OS X > 10.6.2, with 32-bit boost libraries. Boost uses the posix thread > system here. > I boiled my app down to some test code that runs as a command-line > app. It's a bit longer than I'd like, but this configuration seems to > be necessary to invoke the problem. The test uses a queue to pass > "tasks" from the main thread to worker threads, and another queue to > pass "results" back to the main thread. The problem is most apparent > when all the tasks are finished and the queue empties, so that all the > worker threads are waiting on the input queue when the main thread > sends interrupt_all. > > I've looked at the waiting thread in a debugger when this happens, and > found that it has been interrupted, but is still waiting on the > condition. It looks like it just got missed by the interrupt_all. This > is more likely to happen when there are a lot of worker threads (16, > or one per core in my testing). > > The test code is parked at <http://sb.org/ThreadTest.zip>, 20KB. It's > an XCode 3.2 project, but the five source files could be readily > compiled and run in any Unix environment. > > I don't see any errors in the code that could cause these failures. > There is a work-around, which is to interrupt the waiting thread > again. This required a modified version of thread_group so I could do > a timed_join_all on it. > > I welcome any suggestions about what could be wrong here, or ways to > simplify the test to make it more suitable for a bug report. > > - Stoney -- Stonewall Ballard stoney(a)sb.org http://stoney.sb.org/

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Newbie question
by Michael Qi 07 Dec '09

07 Dec '09

Hi, I am trying to start to learn boost. Now, I am learning the getting started guide. And try to build a boost regex program in the guide. But Visual C++ 7.1 tell me error: LINK : fatal error LNK1104: Could not open file "D:\Program.obj" Could you help me? Thank you

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[serialization] speed & size optimized binary archive
by Sebastian Karlsson 04 Dec '09

04 Dec '09

I'm trying to create a binary archive which manages serialization of derived type through base and archive versioning ( not on a type by type basis ). Looking at the binary archive which ships with the distribution it serializes a whole lot of things which is unnecessary for our use case. Going by the documentation and looking on how other archives are implemented I've created a basic implementation, which while compiling doesn't handle serialization of exported types. Even though the documentation is mostly great, this is a small area which seems to be left out, namely the requirements of an archive to be able to serialize / deserialize exported types properly. Looking at the provided archive types it's not clearly distinguishable exactly what's needed for this functionality. The documentation mentions BOOST_SERIALIZATION_REGISTER_ARCHIVE, which is used for the archive. Also, it would be great to know more in depth what actually gets serialized, even if it's subject of change for newer versions. For example, I'm interested in knowing how serialization of exported types will impact archive size. I'm thinking just an extra id per instance? Reading the documentation I got a hunch that extra meta data on a per type basis gets serialized to the archive as well. Under "Types used by the serialization library" several types are mentioned, which of these can be ignored for our use case? This is a reduced form of the output archive which together with an analogous input archive doesn't manage to serialize derived types through their base even if exported, checked to work with the supplied binary archive type. class BinaryOArchive : public boost::archive::detail::common_oarchive< BinaryOArchive > { typedef std::ostream Sink; friend class boost::archive::save_access; template< typename Type > void save( Type& a_Type ) { m_Out.write( reinterpret_cast< const char* >( &a_Type ), sizeof( Type ) ); } public: BinaryOArchive( Sink& a_Out ) : m_Out( a_Out ) {} void save_binary( void *a_Address, std::size_t a_Count ) { m_Out.write( static_cast< const char* >( a_Address ), a_Count ); } private: Sink& m_Out; }; #include "boost/archive/impl/archive_serializer_map.ipp" BOOST_SERIALIZATION_REGISTER_ARCHIVE(Altus::BinaryOArchive) BOOST_SERIALIZATION_USE_ARRAY_OPTIMIZATION(Altus::BinaryOArchive)

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compare strings??
by pedro chaparro 03 Dec '09

03 Dec '09

hi, i need to know how to compare two strings S1 and S2 , i've found fuction is_iequal and is_equal but i dont understand how use it =(, can anyone give me a example? thanks <http://www.boost.org/doc/libs/1_41_0/doc/html/boost/algorithm/is_iequal.html> -- 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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boost asio - async_read and deadline_timer don't call their handler functions
by Gözde Bahar KOŞ 03 Dec '09

03 Dec '09

Hello, I want to use asio library for my serial communication module but I'm having trouble on asynchronous functionality. In the following code block, I wanted to read 5 bytes from the first serial port of my computer in 10 seconds. But none of the handler functions were called. Firstly I waited not inputing any bytes but timer did not call wait_handler. Secondly I sent 5 bytes in 10 seconds from the other computer but read_handler was not called. I could read the bytes using synchronous functions like read function, I mean there is nothing wrong with the communication. I tried this code both on a Windows and a Linux host but results were the same.. Can you please check what can be wrong with the following code? ************************************************************** #include <iostream> #include <boost/asio.hpp> #include <boost/asio/buffer.hpp> #include <boost/asio/deadline_timer.hpp> using namespace std; using namespace boost::asio; using namespace boost::system; using namespace boost::posix_time; struct wait_handler { void operator()(const error_code& ec){ cout << "Timeout!" << endl; } }; struct read_handler { void operator()(const error_code& ec, size_t bytes_transferred) { cout << "Data read!" << endl; } }; int main(int argc, char* argv[]) { char read_msg_[5]; io_service io; serial_port theport(io, "com1"); deadline_timer * timer = new deadline_timer(io); timer->expires_from_now(seconds(10)); wait_handler whandler; timer->async_wait(whandler); read_handler rhandler; async_read(theport, buffer(read_msg_, 5), rhandler); Sleep(30000); //30 seconds return 0; } ************************************************************** Best Regards, Gözde Bahar Koş ###################################################################### Dikkat: Bu elektronik posta mesaji kisisel ve ozeldir. Eger size gonderilmediyse lutfen gondericiyi bilgilendirip mesaji siliniz. Firmamiza gelen ve giden mesajlar virus taramasindan gecirilmekte, guvenlik nedeni ile kontrol edilerek saklanmaktadir. Mesajdaki gorusler ve bakis acisi gondericiye ait olup Aselsan A.S. resmi gorusu olmak zorunda degildir. ###################################################################### Attention: This e-mail message is privileged and confidential. If you are not the intended recipient please delete the message and notify the sender. E-mails to and from the company are monitored for operational reasons and in accordance with lawful business practices. Any views or opinions presented are solely those of the author and do not necessarily represent the views of the company. ######################################################################

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Re: [Boost-users] boost lambda for processing std::vector
by CR Koudella 02 Dec '09

02 Dec '09

Thanks for your answer. I see, I am pretty out of time here. I will look into phoenix. Can you provide an indication as to how you would handle my example with phoenix? That would be of great help. PS: If this message doesn't end up in the right thread, I apologize. I haven't figured out how to reply to the list... Do I have to not user list receive messages in a digest, but receive them one by one?

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thread_group::interrupt_all is not reliable
by Stonewall Ballard 01 Dec '09

01 Dec '09

I've discovered that under circumstances apparently related to timing and load, sending interrupt_all to a thread_group when all the threads are waiting on a boost::condition_variable leaves one thread waiting about 1/3 of the time. This is with boost 1_40_0 running on Mac OS X 10.6.2, with 32-bit boost libraries. Boost uses the posix thread system here. I boiled my app down to some test code that runs as a command-line app. It's a bit longer than I'd like, but this configuration seems to be necessary to invoke the problem. The test uses a queue to pass "tasks" from the main thread to worker threads, and another queue to pass "results" back to the main thread. The problem is most apparent when all the tasks are finished and the queue empties, so that all the worker threads are waiting on the input queue when the main thread sends interrupt_all. I've looked at the waiting thread in a debugger when this happens, and found that it has been interrupted, but is still waiting on the condition. It looks like it just got missed by the interrupt_all. This is more likely to happen when there are a lot of worker threads (16, or one per core in my testing). The test code is parked at <http://sb.org/ThreadTest.zip>, 20KB. It's an XCode 3.2 project, but the five source files could be readily compiled and run in any Unix environment. I don't see any errors in the code that could cause these failures. There is a work-around, which is to interrupt the waiting thread again. This required a modified version of thread_group so I could do a timed_join_all on it. I welcome any suggestions about what could be wrong here, or ways to simplify the test to make it more suitable for a bug report. - Stoney -- Stonewall Ballard stoney(a)sb.org http://stoney.sb.org/

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[Ubuntu 8.04] Linking Problem in Eclipse with Boost 1.41 Libraries
by Brooks Garrison 01 Dec '09

01 Dec '09

Hello all, My question is concerning the Boost installation process. I am currently working on a machine that has Ubuntu 8.04 LTS. I have downloaded the latest copy of Boost (1.41.0) and am trying to successfully install it. I have followed the procedures for building the libraries such as Filesystem / Regex / Thread / etc. using both the bootstrap, "easy", method and the "build custom binaries" method. I'm using Eclipse as my C++ development environment and I can create programs that use the Boost headers (the ones that do not require compilation - ie. Lambda) just fine. When I try to implement the sample program that incorporates [regex], I am able to compile and link just fine. I've set the include directory to ( /usr/local/boost_1_41_0/prefix/include - prefix was just the name I gave the folder), the library search path to ( /usr/local/boost_1_41_0/prefix/lib ) and the library I wanted to link to, [regex], using (boost_regex - I have also tried boost_regex-gcc##-mt ). As I said though, when I try to run the program, I get the result: ./boost_regex_test: error while loading shared libraries: libboost_regex.so.1.41.0: cannot open shared object file: No such file or directory I have not specified that I was using shared libraries, so I do not understand why it is trying to look for them. If anyone could please clarify why this is happening, I'd be more than greatful. Just as an aside, I also tried downloading and installing Boost from the Synaptic Package Manager that comes with Ubuntu 8.04. I'm able to use all of the libraries when I do this, but I'd rather not because the version of Boost is 1.34.1 (quite archaic) and has cause problems because member variables have evolved and some no longer exist. Thanks again for any and all help.

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[Serialization - 1.35] Crash while serializing
by Soumen 01 Dec '09

01 Dec '09

Hi, I've following class hierarchy: FilterCondition <---+--- CompositeCondition | +--- ConcreteCondition FilterCondition is ABC. FilterCondition has certain data members which I need to serialize. I already have another class "Table" for which serialization works perfectly. Now, I've added a pointer of type "FilterCondition" as a member to "Table". Say, the member name is "filterCond_". Now, as soon as I add following line in Table::serialize(), I get a crash : ar & filterCond_; This happens even though I make body of FilterCondition::serialize(), CompositeCondition::serialize() and ConcreteCondition::serialize() empty. In Table::serialize(), I've verified that filterCond_ is a valid pointer. I've declared FilterCondition as abstract through BOOST_CLASS_ABSTRACT macro as well. Following is top of stack from gdb: ------------------------------------------------------------------------------------------------ (gdb) where #0 0x0000000000fcfee6 in boost::serialization::detail::extended_type_info_typeid_0::less_than () #1 0x0000000000fcf703 in boost::serialization::extended_type_info::operator< () #2 0x0000000000fcf78b in boost::serialization::extended_type_info::find () #3 0x0000000000fcffea in boost::serialization::detail::extended_type_info_typeid_0::get_derived_extended_type_info () #4 0x000000000136ca0c in boost::serialization::detail::extended_type_info_typeid_1<FilterCondition const>::get_derived_extended_type_info (t=@0x19c6e390) at /remote/arch-tools/boost/qsc-b/1_35_0/include/boost/serialization/extended_type_info_typeid.hpp:92 #5 0x000000000136ca5b in boost::archive::detail::save_pointer_type<boost::archive::binary_oarchive, FilterCondition*>::polymorphic<FilterCondition>::save (ar=@0x7fbfffc410, t=@0x19c6e390, bpos_ptr=0x0) at /remote/arch-tools/boost/qsc-b/1_35_0/include/boost/archive/detail/oserializer.hpp:385 #6 0x000000000136cbed in boost::archive::detail::save_pointer_type<boost::archive::binary_oarchive, FilterCondition*>::save<FilterCondition> (ar=@0x7fbfffc410, t=@0x19c6e390, bpos_ptr=0x0) at /remote/arch-tools/boost/qsc-b/1_35_0/include/boost/archive/detail/oserializer.hpp:434 #7 0x000000000136cc4a in boost::archive::detail::save_pointer_type<boost::archive::binary_oarchive, FilterCondition*>::invoke (ar=@0x7fbfffc410, t=0x19c6e390) at /remote/arch-tools/boost/qsc-b/1_35_0/include/boost/archive/detail/oserializer.hpp:462 #8 0x000000000136cc6c in boost::archive::save<boost::archive::binary_oarchive, FilterCondition*> (ar=@0x7fbfffc410, t=@0x19c6d820) at /remote/arch-tools/boost/qsc-b/1_35_0/include/boost/archive/detail/oserializer.hpp:532 #9 0x000000000136cc96 in boost::archive::detail::common_oarchive<boost::archive::binary_oarchive>::save_override<FilterCondition* const> (this=0x7fbfffc410, t=@0x19c6d820) at /remote/arch-tools/boost/qsc-b/1_35_0/include/boost/archive/detail/common_oarchive.hpp:64 #10 0x000000000136ccbb in boost::archive::array::oarchive<boost::archive::binary_oarchive>::save_override<FilterCondition*> (this=0x7fbfffc410, x=@0x19c6d820, version=0) at /remote/arch-tools/boost/qsc-b/1_35_0/include/boost/archive/array/oarchive.hpp:122 #11 0x000000000136cce3 in boost::archive::basic_binary_oarchive<boost::archive::binary_oarchive>::save_override<FilterCondition*> (this=0x7fbfffc410, t=@0x19c6d820) at /remote/arch-tools/boost/qsc-b/1_35_0/include/boost/archive/basic_binary_oarchive.hpp:64 #12 0x000000000136cd0b in boost::archive::binary_oarchive_impl<boost::archive::binary_oarchive, char, std::char_traits<char> >::save_override<FilterCondition* const> (this=0x7fbfffc410, t=@0x19c6d820) at /remote/arch-tools/boost/qsc-b/1_35_0/include/boost/archive/binary_oarchive_impl.hpp:45 #13 0x000000000136cd38 in boost::archive::detail::interface_oarchive<boost::archive::binary_oarchive>::operator<< <FilterCondition* const> (this=0x7fbfffc410, t=@0x19c6d820) at /remote/arch-tools/boost/qsc-b/1_35_0/include/boost/archive/detail/interface_oarchive.hpp:64 #14 0x000000000136cd69 in boost::archive::detail::interface_oarchive<boost::archive::binary_oarchive>::operator&<FilterCondition*> (this=0x7fbfffc410, t=@0x19c6d820) at /remote/arch-tools/boost/qsc-b/1_35_0/include/boost/archive/detail/interface_oarchive.hpp:72 #15 0x000000000136ce5a in Table::serialize<boost::archive::binary_oarchive> (this=0x19c6d750, ar=@0x7fbfffc410, version=0) at /remote/scratch/gsoumen/hiers/tmp.trunk/tools/code/tables/Table.h:178 #16 0x000000000136ce7f in boost::serialization::access::serialize<boost::archive::binary_oarchive, Table> (ar=@0x7fbfffc410, t=@0x19c6d750, file_version=0) at /remote/arch-tools/boost/qsc-b/1_35_0/include/boost/serialization/access.hpp:109 ------------------------------------------------------------------------------------------------ Is this a bug in serialization library? Regards, ~ Soumen -- View this message in context: http://www.nabble.com/-Serialization---1.35--Crash-while-serializing-tp2553… Sent from the Boost - Users mailing list archive at Nabble.com.

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Boost Program Options: Just curiosity, why double dashes ?
by Mauricio Gomes 01 Dec '09

01 Dec '09

I am studying Boost Program Options library and I am curious, why was it choosen double dashes as the token to identify an option in the command line ? Example: my_program --help Would not a single dash be enough and less verbose ? What is the rationale behind that ? Thanks, -- Mauricio Gomes "Think globally, act locally".

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