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

[REGEX] seg fault
by John Robertson 30 Oct '09

30 Oct '09

When running the credit_card snippet in gdb I get. Program received signal SIGSEGV, Segmentation fault. 0x00002ac3263b38f2 in boost::re_detail::cpp_regex_traits_implementation<char>::lookup_classname_imp () from /usr/lib64/libboost_regex.so.2 I'm using BOOST_VERSION 103900 Thanks -JR

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program_options wchar_t support (again)
by Yang Zhang 30 Oct '09

30 Oct '09

Last mentioned I could find was 5 years ago: http://lists.boost.org/Archives/boost/2004/02/61057.php Has this been fixed? -- Yang Zhang http://www.mit.edu/~y_z/

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Incorrect parameters problem
by Mathew Benson 30 Oct '09

30 Oct '09

My project was compiling and executing, but I get an error now. I'm not sitting at my desk right now, but I think it said "Incorrect parameters" when I examine the error. Here's the offending code: boost::asio::io_service io_service; using boost::asio::ip::udp; udp::socket s(io_service, udp::endpoint(udp::v4(), 0)); udp::resolver resolver(io_service); udp::resolver::query query(udp::v4(), "127.0.0.1", 606); try { udp::resolver::iterator iterator = resolver.resolve(query); s.send_to(boost::asio::buffer(buffer, size), *iterator); } catch ( std::exception& e ) { std::cout << e.what() << std::endl; } The first line in the try block is what causes the exception. I thought I backed out all my changes, but I still can't get it to work. Can somebody tell me what obvious dumb mistake I made?

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[Serialization] XML serialization of class with abstract template ancestors
by Terry Roberts 30 Oct '09

30 Oct '09

Hi, I'm having some trouble using the Serialization library with a class derived from an abstract template (example code below). What I'd like to do is serialize instances of the derived type through a base class pointer (polymorphic) using the XML archive. The code below works fine using both the text and binary archives, but fails at runtime with the XML archive. The exception thrown is boost::archive::xml_archive_exception with the message "uninitialized exception". My environment: GCC 4.1.2 on RHEL 5.3 Boost v1.37 I've also attempted to use Boost 1.40 (although I didn't see anything to suggest relevant changes), which results in link errors (undefined references to members of boost::archive::detail::archive_serializer_map<boost::archive::xml_iarchive> and boost::serialization::void_cast_detail::void_caster among others). Any help would be appreciated. Thanks. #include <iostream> #include <string> #include <sstream> #include <boost/serialization/serialization.hpp> #include <boost/archive/xml_iarchive.hpp> #include <boost/archive/xml_oarchive.hpp> #include <boost/serialization/export.hpp> class AbstractBase { public: AbstractBase(const std::string& n):name(n) {} virtual ~AbstractBase() {} virtual std::ostream& print(std::ostream& os) const = 0; protected: AbstractBase():name("UNKNOWN BASE") {} friend class boost::serialization::access; template<class Archive> void serialize(Archive& ar, const uint32_t version) { ar & BOOST_SERIALIZATION_NVP(name); } std::string name; }; template <class T> class AbstractTemplate : public AbstractBase { public: AbstractTemplate(const std::string& n):AbstractBase(n) {} virtual ~AbstractTemplate() {} virtual void doSomething(const T& t) = 0; protected: AbstractTemplate():AbstractBase("UKNOWN TEMPLATE") {} friend class boost::serialization::access; template<class Archive> void serialize(Archive& ar, const uint32_t version) { ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(AbstractBase); } }; class Derived : public AbstractTemplate<std::string> { public: Derived(const std::string& n):AbstractTemplate<std::string>(n) {} virtual ~Derived() {} std::ostream& print(std::ostream& os) const { return os << "Derived name: " << name << std::endl; } void doSomething(const std::string& str) { print(std::cout << str << ": "); } protected: Derived():AbstractTemplate<std::string>("UNKNOWN DERIVED") {} friend class boost::serialization::access; template<class Archive> void serialize(Archive& ar, const uint32_t version) { ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(AbstractTemplate<std::string>); } }; BOOST_CLASS_EXPORT(Derived) namespace boost { template <> struct is_abstract<AbstractBase > { typedef mpl::bool_<true> type; BOOST_STATIC_CONSTANT(bool, value = true); }; template<class T> struct is_abstract<AbstractTemplate<T> > { typedef mpl::bool_<true> type; BOOST_STATIC_CONSTANT(bool, value = true); }; } // namepsace boost int main(int argc, char** argv) { static const char XML_NAME[] = "Stuff"; Derived* d = new Derived("test 1"); AbstractTemplate<std::string>* at = d; AbstractBase* ab = d; std::cout << "before serialization:" << std::endl; d->doSomething("something"); at->print(std::cout); ab->print(std::cout); /* serialization */ std::stringstream ss; { boost::archive::xml_oarchive xmlOut(ss); xmlOut << boost::serialization::make_nvp(XML_NAME, ab); } delete ab; ab = NULL; std::cout << "Serialization:" << std::endl << ss.str() << std::endl; /* deserialization */ { boost::archive::xml_iarchive xmlIn(ss); xmlIn >> boost::serialization::make_nvp(XML_NAME, ab); } at = dynamic_cast<AbstractTemplate<std::string>*>(ab); d = dynamic_cast<Derived*>(ab); if ((ab == NULL) || (at == NULL) || (d == NULL)) { std::cout << "deserialization failed" << std::endl; return EXIT_FAILURE; } std::cout << "after deserialization:" << std::endl; d->doSomething("something"); at->print(std::cout); ab->print(std::cout); delete ab; return EXIT_SUCCESS; }

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Compile warnings
by HT4N - 30 Oct '09

30 Oct '09

When I compile the boost spirit with VisualStudio I got the following warnings. Is this a known issue/bug? /* c:\src\indexserve2\private\shared\boost\spirit\tree\impl\tree_to_xml.ipp(66) : warning C4996: 'std::ctype<wchar_t>::wide Function call with parameters that may be unsafe - this call relies on the caller to check that the passed values are correct. To disable this warning, use -D_SCL_SECURE_NO_WARNINGS. See documentation on how to use Visual C++ 'Checked Iterators' */ #pragma warning(disable:4996) /* c:\src\indexserve2\private\shared\boost\spirit\tree\parse_tree.hpp(213) : warning see reference to class template instantiation 'boost::spirit::skip_parser_iteration_policy<ParserT>' being compiled c:\src\indexserve2\private\shared\boost\spirit\core\scanner\skipper.hpp(147) : warning C4512: 'boost::spirit::skip_parse r_iteration_policy<ParserT>' : assignment operator could not be generated */ #pragma warning(disable:4512) _________________________________________________________________ Windows 7: It helps you do more. Explore Windows 7. http://www.microsoft.com/Windows/windows-7/default.aspx?ocid=PID24727::T:WL…

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[lambda] delayed assignment to a member
by Igor R 29 Oct '09

29 Oct '09

Hello, How can I create a functor, which would assign to a member variable, when invoked? I mean, something like this: int member_; //... lambda::bind(my_obj::member_, this, 5); The above bind itself compiles, but if I try to invoke it or to assign to a function<void()>, it doesn't compile. Thanks.

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[getting IP-header]How do I get the IP-header information
by Mats Carlsson 29 Oct '09

29 Oct '09

Hello, I'm trying to get the IP-header information from an IP-message sent using boost. I can get the message itself by using: void Receiver::wait_for_packet() { socket.async_receive_from(boost::asio::buffer(receive_buffer), remote_endpoint, boost::bind( &Receiver::handle_packet, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); } void Receiver::handle_packet(const boost::system::error_code& error, int bytes_transferred) { if (error) { //throw boost::system::system_error(error); } std::string message; for (int i = 0; i < bytes_transferred; i++) { message += receive_buffer[i]; } std::string payload(message); Packet packet; packet.set_payload(payload); listener->new_packet_received(packet); wait_for_packet(); } Where "message" is the body of the sent stuff. But how do I get to the IP-header things? I've been looking in doc/html/boost_asio/example/serialization/connection.hpp, but do not really get what to do. BR, /Mats Carlsson

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asynch_write fails when used to write long data
by A.Agrawal＠patrick.com.au 29 Oct '09

29 Oct '09

Hi, I have a Client (windows) - server (linux) program which uses boost::asio asynch methods. I am getting error when server writes to client using asynch_write and data is large with size greater than a particular value. ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// std::vector<boost::asio::const_buffer> _buffers; _buffers.push_back(boost::asio::buffer(outbound_header)); _buffers.push_back(boost::asio::buffer(outbound_message)); _buffers.push_back(boost::asio::buffer(outbound_data)); boost::asio::async_write(_socket, _buffers, boost::bind(&ClientSession::handle_write, this, boost::asio::placeholders::error)); ///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// here outbound_header is of type string of length 8 and has value " 202e5" outbound_message is of type string of length 8 and has value " 2" outbound_data when of length 131813. I get error with error_code - val = 14 (Bad Address) If I reduce the outbound_data size to 130812, everything is fine. I am unable to figure out the problem, I thought I can send unlimited size data in a single call. Please advise if you have any idea. I will be more than happy to provide you with information that you may need. Regards, Anil Agrawal PTS

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[Interprocess] Using shared Memory with different compilers (msvc, mingw)
by BaDBuTz 29 Oct '09

29 Oct '09

hi, My library uses boost::interprocess' Shared Memory and has to be delivered with msvc(7.1) and mingw compiled versions. Every instance of the that library opens a connection to the Shared Memory "sharedMemoryMapTest" and communicates via instances of the class "SyncObject". In my test program ProcessA opens the shared memory, instanciates a SynObject with the identifyer String "id1". ProcessB connects to the same SyncObject and synchronizes with ProcessA. If ProcessA and ProcessB are both compiled with the same compiler it works fine. If one process is compiled with mscv and the other is compiled with mingw it fails. (mscv = ProcessA, ProcessB = mingw -> I read my Windows environment variables instead of "id1") Did I make a mistake in my implementation, or is it simply not possible to access the same Shmem with different compiled versions? Thanks in advance Martin (compilable) code: #include <iostream> #include <boost/interprocess/managed_shared_memory.hpp> #include <boost/interprocess/allocators/allocator.hpp> #include <boost/interprocess/containers/string.hpp> #include <boost/interprocess/containers/list.hpp> typedef unsigned long U32; using namespace boost::interprocess; class SyncObject { public: SyncObject(std::string aId) : id(aId), locAddrSp0Range(0), locAddrSp0Remap(0), locAddrSp1Range(0), locAddrSp1Remap(0), usbInterfaceOwner(0), useCounter(0) {} ; ~SyncObject() { std::cout << "SyncObject Destructor\n" << std::flush; }; void print() { std::cout << " id = " << id << " locAddrSp0Range = " << locAddrSp0Range << " locAddrSp0Remap = " << locAddrSp0Remap << " locAddrSp1Range = " << locAddrSp1Range << " locAddrSp1Remap = " << locAddrSp1Remap << " usbInterfaceOwner = " << usbInterfaceOwner << " useCounter = " << useCounter << "\n" << std::flush; }; std::string id; interprocess_mutex mtxReadWrite; interprocess_mutex mtxFunction; U32 locAddrSp0Range; U32 locAddrSp0Remap; U32 locAddrSp1Range; U32 locAddrSp1Remap; U32 usbInterfaceOwner; U32 useCounter; }; const char* MANAGED_SHARED_MEMORY_NAME = "sharedMemoryMapTest58"; const char* SYNC_OBJ_LIST_NAME = "sharedMemorySyncList"; typedef offset_ptr<SyncObject> SyncObjOffsetPtr; typedef allocator<SyncObjOffsetPtr, managed_shared_memory::segment_manager> SyncObjOffsetPtrAllocator; typedef list<SyncObjOffsetPtr, SyncObjOffsetPtrAllocator> SyncObjectList; class SharedMemory { public: SharedMemory(); ~SharedMemory(); void printList(); SyncObject* getSyncObject(std::string id); void removeSyncObject(std::string id); private: managed_shared_memory segment; }; SharedMemory::SharedMemory() { segment = managed_shared_memory(open_or_create, MANAGED_SHARED_MEMORY_NAME, 65536); } SharedMemory::~SharedMemory() { std::cout << "SharedMemory Destuctor\n" << std::flush; SyncObjectList* pList = segment.find<SyncObjectList>(SYNC_OBJ_LIST_NAME).first; if (pList) { if (pList->size() < 1) { segment.destroy_ptr(pList); std::cout << "pList destroyed! \n" << std::flush; } } // unlink shared mem object // shared_memory_object::remove(MANAGED_SHARED_MEMORY_NAME); if( shared_memory_object::remove(MANAGED_SHARED_MEMORY_NAME)) std::cout << MANAGED_SHARED_MEMORY_NAME << " successfully removed from the system!\n" << std::flush; else std::cout << MANAGED_SHARED_MEMORY_NAME << " could not be removed from the system!\n" << std::flush; } void SharedMemory::printList() { SyncObjectList* pList = segment.find<SyncObjectList>(SYNC_OBJ_LIST_NAME).first; if (!pList) { std::cout << "List does not exist!\n" << std::flush; return; } std::cout << "list contains: "; for(SyncObjectList::iterator iter = pList->begin(); iter != pList->end(); ++iter ) { std::cout << iter->get()->id << "\t"; } std::cout << "\n" << std::flush; } SyncObject* SharedMemory::getSyncObject(std::string id) { //Initialize shared memory STL-compatible allocator const SyncObjOffsetPtrAllocator syncObjOffsetPtrAllocatorInst (segment.get_segment_manager()); SyncObjectList* pList = segment.find_or_construct<SyncObjectList>(SYNC_OBJ_LIST_NAME)(syncObjOffsetPtrAllocatorInst); printList(); for(SyncObjectList::iterator iter = pList->begin(); iter != pList->end(); ++iter ) { if (iter->get()->id == id) { std::cout << id << " already exists in SHMem! returning pointer\n"; iter->get()->useCounter++; return iter->get(); } } std::cout << id << " is not in the list and will be created in SHMem!\n"; SyncObject* ptr = segment.construct<SyncObject>(id.c_str())(id); ptr->useCounter++; pList->push_back(offset_ptr<SyncObject>(ptr)); return ptr; } void SharedMemory::removeSyncObject(std::string id) { //Initialize shared memory STL-compatible allocator const SyncObjOffsetPtrAllocator syncObjOffsetPtrAllocatorInst (segment.get_segment_manager()); SyncObjectList* pList = segment.find_or_construct<SyncObjectList>(SYNC_OBJ_LIST_NAME)(syncObjOffsetPtrAllocatorInst); printList(); for(SyncObjectList::iterator iter = pList->begin(); iter != pList->end(); ++iter ) { if (iter->get()->id == id) { if (iter->get()->useCounter < 2) { std::cout << "removing " << id << " from list \n" << std::flush; SyncObject *ptr = iter->get(); segment.destroy_ptr(ptr); pList->erase(iter); } else { std::cout << "decrementing userCounter of id " << id << "\n" << std::flush; iter->get()->useCounter--; } break; } } } int main() { try { SharedMemory shm; SyncObject *pSync = shm.getSyncObject("id1"); pSync->mtxFunction.lock(); pSync->print(); pSync->locAddrSp0Range++; pSync->print(); pSync->mtxFunction.unlock(); shm.removeSyncObject("id1"); pSync = shm.getSyncObject("id1"); pSync->mtxFunction.lock(); pSync->print(); pSync->locAddrSp0Range++; pSync->print(); pSync->mtxFunction.unlock(); shm.removeSyncObject("id1"); } catch(boost::interprocess::interprocess_exception &ex) { std::ostringstream sout; sout.str(""); sout << ex.what(); std::cout << sout.str() << std::flush; } return 0; } -- Neu: GMX DSL bis 50.000 kBit/s und 200,- Euro Startguthaben! 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[ptr_container] ptr_vector and ptr_circullar_buffer don't initialize PODs
by Roman Perepelitsa 29 Oct '09

29 Oct '09

ptr_vector<T>::resize creates new objects using 'new T' instead of 'new T()', which results in uninitialized objects if T is a POD. For consistency with STL containers (std::vector in particular) all PODs must be explicitly initialized. Test: #include <cassert> #include <boost/ptr_container/ptr_vector.hpp> int main() { boost::ptr_vector<int> v; v.resize(1); assert(v[0] == 0); // Might fail. } ptr_circullar_buffer has the same problem. I opened a trac ticket (https://svn.boost.org/trac/boost/ticket/3579) and attached a patch to it. Roman Perepelitsa.

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