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

boost serialisation: portable binary format cant cope with -1
by Avi Bahra 09 Mar '10

09 Mar '10

I have a strange bug where on the AIX platform I get: boost::archive exception for TimeStruct : integer cannot be represented for boost version 1.40 on restoring a class(TimeStruct) that has a integer data member of value of -1. Its seems strange that the exception is _only_ raised when restoring the class, and not saving Its missing some symmetry somewhere ? Here is the stack trace: //boost::serialization::throw_exception<portable_binary_iarchive_exception>, //portable_binary_iarchive::load_impl, //portable_binary_iarchive::load<int>, //boost::archive::load_access::load_primitive<portable_binary_iarchive,int>, //boost::archive::detail::load_non_pointer_type<portable_binary_iarchive,int>::load_primitive::invoke, //boost::archive::detail::load_non_pointer_type<portable_binary_iarchive,int>::invoke, //boost::archive::load<portable_binary_iarchive,int>, //boost::archive::detail::common_iarchive<portable_binary_iarchive>::load_override<int>, //portable_binary_iarchive::load_override<int>, //boost::archive::detail::interface_iarchive<portable_binary_iarchive>::operator >><int>, //boost::archive::detail::interface_iarchive<portable_binary_iarchive>::operator &<int>, //TimeStruct::serialize<portable_binary_iarchive>, // ..... This is raised in: void portable_binary_iarchive::load_impl(boost::intmax_t & l, char maxsize){ char size; l = 0; this->primitive_base_t::load(size); if(0 == size){ return; } bool negative = (size < 0); if(negative) size = -size; if(size > maxsize) boost::serialization::throw_exception( portable_binary_iarchive_exception() ); ..... The exception is raised because size=255 and maxsize=4 ? Here is the example which produces the exception: Please note that you will have to dig out and compile the portable binary archives out of the boost serialisation examples dirs. //================ Main.cpp ========================= // This example demonstrates a possible bug in // portable binary format on AIX when serialising -1 // that is specific only to the AIX compiler/platform // (i.e HPUX/Acc and linux/gcc run without any problems) // However on AIX on the restore I get: // boost::archive exception for TimeStruct : integer cannot be represented // // This test consists of 1 files // 1/ Main.cpp // #include <sstream> #include <ostream> #include <iostream> #include <fstream> #include <boost/archive/binary_oarchive.hpp> #include <boost/archive/binary_iarchive.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/archive/text_oarchive.hpp> #include "portable_binary_oarchive.hpp" #include "portable_binary_iarchive.hpp" #include <boost/serialization/serialization.hpp> using namespace std; class TimeStruct { public: TimeStruct() : hour_(-1), minute_(-1) {} TimeStruct(int hour, int min) : hour_(hour), minute_(min) {} bool operator==(const TimeStruct& rhs) const { return ((hour_ == rhs.hour_) && (minute_ == rhs.minute_));} bool operator!=(const TimeStruct& rhs) const { return !operator==(rhs);} int hour() const { return hour_;} int minute() const { return minute_;} bool isNULL() const { return (hour_ == -1) || (minute_ == -1); } // returns struct in the format hh:mm std::string toString() const { std::stringstream ss; if (hour_ == -1) ss << hour_; else if (hour_ < 10) ss << "0" << hour_; else ss << hour_; ss << ":"; if (minute_ == -1) ss << minute_; else if (minute_ < 10) ss << "0" << minute_; else ss << minute_; return ss.str(); } private: int hour_; int minute_; friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int /*version*/) { ar & hour_; ar & minute_; } }; bool compare(const TimeStruct& lhs, const TimeStruct& rhs) { if (lhs.isNULL() && rhs.isNULL()) return true; if (lhs.isNULL() && !rhs.isNULL()) return false; if (!lhs.isNULL() && rhs.isNULL()) return false; if (lhs.hour() != rhs.hour()) return false; if (lhs.minute() != rhs.minute()) return false; return true; }; static void save(const std::string& fileName, const TimeStruct& ts, bool textArchive); static void restore(const std::string& fileName, TimeStruct& ts, bool textArchive); int main() { { TimeStruct saved; save("fred.txt",saved,true); TimeStruct restored; restore("fred.txt",restored,true); assert(saved == restored); } { TimeStruct saved; save("fred.txt",saved,false); TimeStruct restored; restore("fred.txt",restored,false); assert(saved == restored); } return 0; } void save(const std::string& fileName, const TimeStruct& ts, bool textArchive) { if ( textArchive ) std::cout << "Text archive Saving " << ts.toString(); else std::cout << "portable binary archive Saving " << ts.toString(); try { if (textArchive) { std::ofstream ofs( "fred.txt" ); boost::archive::text_oarchive ar( ofs ); ar << ts; } else { std::ofstream ofs( fileName.c_str(), ios::binary ); portable_binary_oarchive ar(ofs); ar << ts; } std::cout << " OK \n"; } catch (const boost::archive::archive_exception& ae) { std::cout << " save " << fileName << " failed. boost::archive exception for TimeStruct " << ": " << ae.what() << std::endl; } } void restore(const std::string& fileName, TimeStruct& restored, bool textArchive) { if ( textArchive ) std::cout << "Text archive Restoring "; else std::cout << "portable binary archive Restoring " ; try { if ( textArchive ) { std::ifstream ifs( fileName.c_str() ); boost::archive::text_iarchive ar( ifs ); ar >> restored; } else { std::ifstream ifs( fileName.c_str(), ios::binary ); portable_binary_iarchive ar( ifs ); ar >> restored; } std::cout << restored.toString() << " OK \n"; } catch ( const boost::archive::archive_exception& ae ) { std::cout << " restore " << fileName << " failed. boost::archive exception for TimeStruct " << ": " << ae.what() << std::endl; } } Best regards, Ta, Avi

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[Boost.Log] Did I miss the formal review start mail?
by Roland Bock 09 Mar '10

09 Mar '10

Hi, a week ago, Vladimir wrote that a formal review of boost.log would start this week. Did I miss the formal mail? Thanks and regards, Roland

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[filesystem] basic_path as parameter
by Alexander Lamaison 09 Mar '10

09 Mar '10

I'd like to use basic_path as a function parameter so that it works correctly whether a wide or narrow string is passed. template<typename T> void func(basic_path<T> file) { do thing to file } func("myfile"); func(L"myfile"); However I can't do this because basic_path has a second Traits template parameter which is not itself a template. So I tried the following workaround: template<typename T> struct traits_chooser; template<> struct traits_chooser<char*> { typedef boost::filesystem::path_traits traits; }; template<> struct traits_chooser<wchar_t*> { typedef boost::filesystem::wpath_traits traits; }; template<typename T> void func(basic_path<T, typename traits_chooser<T>::traits> file) {...} But my compiler (MSVC 2005) still can't deduce the parameter type. Does anyone know how I can get this to work? Many thanks. Alex Lamaison

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[boost::asio] exception not passed to async callback
by Matheus Araújo Aguiar 09 Mar '10

09 Mar '10

Hello list, Right now i am having some problems with a TCP socket waiting for a pending async read operation. When the remote endpoint closes the connection due to some crash or other unexpected situation(i.e, without proper closing of the socket) my application is terminated with this message: "Terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::system::system_error> >' what(): Transport endpoint is not connected Aborted" Maybe i am missing something here, because i expected any boost::system exceptions to be passed to the callback associated with the async read operation. I am assuming that this exception is thrown in the io_service::run method, is that right? If so, why it is not passed to the callback? and what can i do to catch it, having the io_service::run running on a separeted thread? Thanx in advance and best regards, -- Matheus Araújo Aguiar Computer Scientist matheus.pit(a)gmail.com

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Boost.Random question
by gast128 09 Mar '10

09 Mar '10

Hello all, a colleague of my asked me to drop a question on the forum about the following case: He produces 1000 samples with the following code: boost::normal_distribution<double> n1(1, sqrt(4.0)); boost::variate_generator< boost::minstd_rand, boost::normal_distribution<double> > g1(boost::minstd_rand(), n1); He also calulates the covariance. It should be something like (4 0) but he got (4.1 8.3). This 4 is correct, but the 8.3 not. Anyone an idea? Note (again): post from a colleague; i didn't try it myself.

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Boost.Asio tcp::acceptor after close, then open->listen got error!!!!
by l.jay Yuan 09 Mar '10

09 Mar '10

Boost.Asio tcp::acceptor after close, then open->listen got error!!!! cannot reopen?

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[filesystem] basic_path as paramter
by Alexander Lamaison 09 Mar '10

09 Mar '10

I'd like to use basic_path as a function parameter so that it works correctly whether a wide or narrow string is passed. template<typename T> void func(basic_path<T> file) { do thing to file } func("myfile"); func(L"myfile"); However I can't do this becuase basic_path has a second Traits template paramter which is not itself a template. So I tried the following workaround: template<typename T> struct traits_chooser; template<> struct traits_chooser<char*> { typedef boost::filesystem::path_traits traits; }; template<> struct traits_chooser<wchar_t*> { typedef boost::filesystem::wpath_traits traits; }; template<typename T> void func(basic_path<T, typename traits_chooser<T>::traits> file) {...} But my compiler (MSVC 2005) still can't deduce the paramter type. Does anyone know how I can get this to work? Many thanks. Alex Lamaison

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BOOST_ALL_DYN_LINK
by Paul 09 Mar '10

09 Mar '10

Hi all, I'm confused about boost dynamic linking on windows MSVC90 I always define: BOOST_ALL_NO_LIB So that I directly control which DLLs I link to. I add the signals dll for linking. Then, if I define BOOST_ALL_DYN_LINK, I get lots of these messages: boost_1_42_0\boost/signals/detail/signal_base.hpp(113) : warning C4251: 'boost::signals::detail::signal_base_impl::combiner_' : class 'boost::any' needs to have dll-interface to be used by clients of class 'boost::signals::detail::signal_base_impl' 39> boost_1_42_0\boost/any.hpp(36) : see declaration of 'boost::any' I've read up on this and understand why the warnings are shown. BUT, I don't understand why I am able to still link my program if I do NOT define BOOST_ALL_DYN_LINK. Without the flag, it compiles without warnings, it links without problems, AND the executable requires the signals DLL to be available, so clearly it IS dynamically linked. Right? Any ideas? Thanks, Paul

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[serialization] Sets of shared pointers won't load
by John Pallister 09 Mar '10

09 Mar '10

Hello list, I'm using Visual C++ Express 2008 and Boost 1.42. I have a graph of classes I'm trying to serialise, and I'm using shared_ptrs to manage multiple references to the same object, but I can't deserialise my graph corectly. I get errors like: First-chance exception at 0x7c812afb in sams-6.exe: Microsoft C++ exception: std::basic_string<char,std::char_traits<char>,std::allocator<char> > at memory location 0x03d7f28c.. HEAP[sams-6.exe]: Invalid allocation size - AC1051B4 (exceeded 7ffdefff) First-chance exception at 0x7c812afb in sams-6.exe: Microsoft C++ exception: std::bad_alloc at memory location 0x03c7dc5c.. HEAP[sams-6.exe]: Invalid allocation size - AC1051A8 (exceeded 7ffdefff) Here are my classes: struct stats_t { friend class boost::serialization::access; typedef int ts_t; size_t bytes, packets; ts_t firstPacketTs, lastPacketTs; stats_t() : bytes(0), packets(0), firstPacketTs(0), lastPacketTs(0) { } private: template<class Archive> void serialize(Archive &ar, unsigned int /* file_version */) { ar & bytes & packets & firstPacketTs & lastPacketTs; } }; struct dest_port_t { friend class boost::serialization::access; endpoint_t endpoint; shp_socket_t socket; bool inUse; stats_t stats; std::string name; boost::asio::ip::udp::endpoint baue; dest_port_t(const endpoint_t &e, const std::string &n=std::string()) : endpoint(e), inUse(false), name(n), baue(boost::asio::ip::address_v4(e.first), e.second) { } private: template<class Archive> void serialize(Archive &ar, unsigned int /* file_version */) { ar & endpoint & name & inUse & stats; } }; typedef boost::shared_ptr<dest_port_t> shp_dest_port_t; typedef std::set<shp_dest_port_t> dest_port_shpset_t; BOOST_SERIALIZATION_SHARED_PTR( dest_port_t ) namespace boost { namespace serialization { template<class Archive> inline void load_construct_data(Archive &ar, dest_port_t *dpp, unsigned int /* file_version */) { endpoint_t endpoint; std::string name; ar >> endpoint; ar >> name; ::new(dpp) dest_port_t(endpoint, name); ar >> dpp->inUse; ar >> dpp->stats; } } } struct dest_t { friend class boost::serialization::access; endpoint_t endpoint; dest_port_shpset_t ports; size_t connections; std::string name; dest_t(const endpoint_t &e=endpoint_t(), const std::string &n=std::string()) : endpoint(e), connections(0), name(n) { } private: template<class Archive> void serialize(Archive &ar, unsigned int /* file_version */) { ar & endpoint & ports & connections & name; } }; typedef boost::shared_ptr<dest_t> shp_dest_t; typedef std::set<shp_dest_t> dest_shpset_t; BOOST_SERIALIZATION_SHARED_PTR( dest_t ) struct source_t { friend class boost::serialization::access; endpoint_t endpoint; size_t connections; stats_t stats; const bool foreign; // True for 'unrecognised' sources. std::string name; source_t(const endpoint_t &e=endpoint_t(), bool f=false, const std::string &n=std::string()) : endpoint(e), connections(0), foreign(f), name(n) { } private: template<class Archive> void serialize(Archive &ar, unsigned int /* file_version */) { ar & endpoint & connections & stats & const_cast<bool &>(foreign) & name; } }; typedef boost::shared_ptr<source_t> shp_source_t; typedef std::set<shp_source_t> source_shpset_t; BOOST_SERIALIZATION_SHARED_PTR( source_t ) struct connection_t { friend class boost::serialization::access; shp_source_t source; shp_dest_port_t dest_port; shp_dest_t dest; stats_t stats; connection_t(const shp_source_t &s, const shp_dest_port_t &dp, const shp_dest_t &d=shp_dest_t()) : source(s), dest_port(dp), dest(d) { } private: template<class Archive> void serialize(Archive &ar, unsigned int /* file_version */) { ar & source & dest_port & dest & stats; } }; typedef std::set<connection_t> connection_set_t; typedef std::map<endpoint_t, connection_set_t> talkspurt_map_t; namespace boost { namespace serialization { template<class Archive> inline void load_construct_data(Archive &ar, connection_t *cp, unsigned int /* file_version */) { shp_source_t src; shp_dest_port_t dest_port; shp_dest_t dest; ar >> src; ar >> dest_port; ar >> dest; ::new(cp) connection_t(src, dest_port, dest); ar >> cp->stats; } } } class UdpWorker : public syn::Thread { protected: size_t errors_; stats_t total_, invalid_, ignored_; dest_shpset_t dests_; source_shpset_t sources_; talkspurt_map_t talkspurtMap_; }; So it's UdpWorker -> dest_shpset_t -> dest_t -> dest_port_shpset_t -> stats_t, UdpWorker -> source_shpset_t -> source_t -> stats_t, UdpWorker -> talkspurt_map_t -> connection_set_t -> shp_source_t etc. The code to save is: void UdpWorker::save() { try { ofstream os(stateFile_.c_str()); boost::archive::text_oarchive oa(os); oa << errors_; oa << total_; oa << invalid_; oa << ignored_; oa << sources_; oa << dests_; oa << talkspurtMap_; } catch (boost::archive::archive_exception &ae) { log("UdpWorker::save(): Error - caught archive_exception \"%s\" while saving to text archive \"%s\".", ae.what(), stateFile_.c_str()); } catch (...) { log("UdpWorker::save(): Error - caught unknown exception while saving to text archive \"%s\".", stateFile_.c_str()); } } And the loading code is very similar: void UdpWorker::load() { try { ifstream is(stateFile_.c_str()); boost::archive::text_iarchive ia(is); ia >> errors_; ia >> total_; ia >> invalid_; ia >> ignored_; ia >> sources_; ia >> dests_; ia >> talkspurtMap_; } catch (boost::archive::archive_exception &ae) { log("UdpWorker::load(): Error - caught archive_exception \"%s\" while loading from text archive \"%s\".", ae.what(), stateFile_.c_str()); } catch (...) { log("UdpWorker::load(): Error - caught unknown exception while loading from text archive \"%s\".", stateFile_.c_str()); } } The archive seems to be written OK, but when loading it seems to load the sources_ set OK and then die on the dests_ set, with the bad_alloc exceptions given above. So the talkspurt_map_t hasn't been tested yet... I've tried the binary archive, but I get pretty much the same error. I'd really appreciate it if someone with a more experienced eye could have a look at my classes and tell me if there's anything suspicious. Is BOOST_SERIALIZATION_SHARED_PTR still required in 1.42? I couldn't find any mention of it in the documentation, but many examples seem to use it. It looks like it's a no-op anyway on this compiler. Thanks very much, John :^P -- John Pallister john(a)johnp.net john(a)synchromesh.com

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Using Boost.Atomic for thread-safe reference counting with strong exception guarantee
by Narcoleptic Electron 08 Mar '10

08 Mar '10

I'm trying to create a thread-safe, strong-exception-guaranteed "intrusive_pte" (intrusive pointee) class that represents a drop-in reference-counted base class for a pointee of intrusive_ptr. I'm using the pending Boost.Atomic library (http://www.chaoticmind.net/~hcb/projects/boost.atomic/) and am basing my code on the example given (http://www.chaoticmind.net/~hcb/projects/boost.atomic/doc/atomic/usage_exam…) but not yet having a sound understanding of memory barriers, I am unsure if my code for the overflow exception is correct or ideal. The relevant code snippet is below. Any feedback would be greatly appreciated. Thanks! --- mutable atomic< IntegralType > ref_count; mutable mutex add_ref_mutex; void add_ref() const { mutex::scoped_lock add_ref_lock( add_ref_mutex ); if ( integer_traits< IntegralType >::const_max == ref_count.load( memory_order_relaxed ) ) { throw_exception( std::overflow_error( "Reference count overflow." ) ); } ref_count.fetch_add( 1, memory_order_relaxed ); } friend void intrusive_ptr_add_ref ( intrusive_pte const * const p ) { BOOST_ASSERT( p && "The argument cannot be null." ); p->add_ref(); } friend void intrusive_ptr_release ( intrusive_pte * const p ) { BOOST_ASSERT( p && "The argument cannot be null." ); BOOST_ASSERT( ( 0 < p->ref_count.load( memory_order_acquire ) ) && "Reference count underflow." ); if ( p->ref_count.fetch_sub( 1, memory_order_release ) == 1 ) { atomic_thread_fence( memory_order_acquire ); checked_delete( p ); } }

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