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[type_traits] Check if implicit conversion from one type to another is possible
by Aaron Levy 29 Oct '14

29 Oct '14

Which is the correct type trait to use to check if an element of type T can be assigned to an element of type U. Is it any of the following: boost::is_convertible<T, U> std::is_assignable<U, T> Now boost::is_convertible<double, int>::value is true while std::is_assignable<int, double>::value is false. What does this signify? -- Aaron Levy aaron.levy(a)yandex.com

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bjam hangs on select (in develop branch)
by Alain Miniussi 28 Oct '14

28 Oct '14

Hi, I am trying to test Boost.MPI with Intel's implementation and I am stuck while trying to run simple tests through bjam. Bjam is hangs on the select (not pselect ?) instruction of the unix exec_wait. As far as processes are concerned: PID USER PR NI S %CPU TIME+ PPID COMMAND ....................... 16882 alainm 20 0 S 0.0 0:01.61 6507 bjam 16899 alainm 20 0 T 0.0 0:00.00 16882 sh 16900 alainm 20 0 Z 0.0 0:00.00 16899 mpiexec.hydra <defunct> ....... bjam calls a generated shell (below) which calls a mpiexe.hydra which work perfectly fine outside bjam. The mpiexec.hydra dies the the shell refuses to let it go. the shell script, generated by bjam, is: =============================================== [alainm@gurney engine]$ more /proc/16899/cmdline /bin/sh LD_LIBRARY_PATH="/gpfs/scratch/alainm/view/boost/bin.v2/libs/mpi/build/intel-linux/debug:/gpfs/scratch/alainm/view/boost/bin.v2/libs/serialization/build/intel-linux/debug:/softs/ intel/composer_xe_2015.0.090/bin/lib:/softs/intel/composer_xe_2015.0.090/lib/intel64:$LD_LIBRARY_PATH" export LD_LIBRARY_PATH status=0 if test $status -ne 0 ; then echo Skipping test execution due to testing.execute=off exit 0 fi mpiexec.hydra -n 2 "../../../bin.v2/libs/mpi/test/broadcast_stl_test-2.test/intel-linux/debug/broadcast_stl_test-2" blob > "../../../bin.v2/libs/mpi/test/broadcast_stl_test-2.te st/intel-linux/debug/broadcast_stl_test-2-run.output" 2>&1 status=$? echo >> "../../../bin.v2/libs/mpi/test/broadcast_stl_test-2.test/intel-linux/debug/broadcast_stl_test-2-run.output" echo EXIT STATUS: $status >> "../../../bin.v2/libs/mpi/test/broadcast_stl_test-2.test/intel-linux/debug/broadcast_stl_test-2-run.output" if test $status -eq 0 ; then cp "../../../bin.v2/libs/mpi/test/broadcast_stl_test-2.test/intel-linux/debug/broadcast_stl_test-2-run.output" "../../../bin.v2/libs/mpi/test/broadcast_stl_test-2.test/intel- linux/debug/broadcast_stl_test-2-run" fi verbose=0 if test $status -ne 0 ; then verbose=1 fi if test $verbose -eq 1 ; then echo ====== BEGIN OUTPUT ====== cat "../../../bin.v2/libs/mpi/test/broadcast_stl_test-2.test/intel-linux/debug/broadcast_stl_test-2-run.output" echo ====== END OUTPUT ====== fi exit $status [alainm@gurney engine]$ ================================================= Note that select only test for the subprocess output, at the hanging point mpiexec.hydra is done with its outputs. Any idea ? Alain PS: there was a cmake based project some time ago, is it still active or is bjam here to stay ?

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[Boost.Polygon] Union filling holes
by Julien Nicoulaud 27 Oct '14

27 Oct '14

Hi all, I am using boost/polygon to do unions of multiple polygons, and I lose holes that were in the input after the assign() operation. Here is code that demonstrates the issue: // Create outer contour Point outer[] = {gtl::construct<Point>(0, 0), gtl::construct<Point>(0, 10), gtl::construct<Point>(10, 10), gtl::construct<Point>(10, 0)}; // Create inner contour Point inner[] = {gtl::construct<Point>(2, 2), gtl::construct<Point>(8, 2), gtl::construct<Point>(8, 8), gtl::construct<Point>(2, 8)}; // Define inner contour as a polygon polygon_with_holes_data<long> input_poly_inner; gtl::set_points(input_poly_inner, inner, inner+4); // Put inner polygon in a list vector<polygon_with_holes_data<long> > inners; inners.push_back(input_poly_inner); // Create input polygon as outer contour + inner polygon list polygon_with_holes_data<long> input_poly; gtl::set_points(input_poly, outer, outer+4); gtl::set_holes(input_poly, inners.begin(), inners.end()); // Create input polygon set, insert input polygon polygon_set_data<long> input_poly_set; input_poly_set.insert(input_poly); // Create output polygon set, assign input polygon set vector<polygon_with_holes_data<long> > output_poly_set; assign(output_poly_set, input_poly_set); // Print result std::cout << output_poly_set.size() << " polys" << std::endl; std::cout << output_poly_set[0].size_holes() << " holes" << std::endl; This prints: 1 polys 0 holes Any idea what I am doing wrong ? Kind regards, Julien Nicoulaud

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1.57.0 beta 1 is in a new location
by Marshall Clow 27 Oct '14

27 Oct '14

Tom Kent pointed out that I put the beta 1 files in a folder that we traditionally use for Windows binaries, so I have moved the beta files to https://sourceforge.net/projects/boost/files/boost/1.57.0.beta.1/ These are the same files as last Monday - merely in a new location. If you have already downloaded and tested the beta, thanks! - no need to do it again. — Marshall

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[Geometry] Packing algorithm for r-tree?
by Jeremy Murphy 27 Oct '14

27 Oct '14

I see that a fourth node splitting algorithm for bulk loading is documented in the Introduction to spatial indexes but not listed elsewhere (such as Creation and Modification). Is it hiding in the library somewhere or is the introduction just a tantalizing sneak preview? Thanks, cheers. Jeremy

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BGL, cut set
by Mads Jensen 27 Oct '14

27 Oct '14

Hi, I'm looking into how you can quickly find the cut set of a graph without having to loop over the colormap as a vector. I'm using the http://www.boost.org/doc/libs/1_56_0/libs/graph/doc/edmonds_karp_max_flow.h… (the example provided does mostly what I want, except that it uses a vector, and not a regular map). Boykov Kolmogorov also has the colormap parameter. It seems that associative_property_map could be used, but I don't really see how? Hints on how to do this will be appreciated. A lot of the examples of the Boost graph library use the preprocessor with a check similar to: #if defined(BOOST_MSVC) && BOOST_MSVC <= 1300 What's so special about this? Thank you, -- Med Venlig Hilsen / Kind regards, Mads Jensen

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[Serialization] Deserialization of base class fails
by Torsten Wylegala 25 Oct '14

25 Oct '14

Hi, I'm currently trying to serialize and deserialize a derived class using boost::archive::xml_iarchive/xml_oarchive Version 1.52. Everything works fine as long as I serialize and deserialize the same class (Example 1). The attributes of the derived class and the base class are both serialized and the deserialized correctly and requestPackageOut equals requestPackageIn (the base-class attributes are equal too). But if I serialize the derived class "RequestPackage" and try to deserialize it into the base-class "Package" (Example 2) I'm getting an "input stream error" exception while trying to deserialize with ia >> BOOST_SERIALIZATION_NVP(*package);. I'm quite new to this topic and found a lot of posting but none of them seems to match and solve my exact problem. It would by very nice if somebody could help me with that. Background information: I want to use xml-serialized objects for data exchange via network and want all the packages to inherit from Package-class which carries "packageId" and therefore give me the chance to identify the incoming xml-objects and handle every package based on this id. If some information is missing I will do my best to provide it later. Torsten Example 1: int main(int argc, char** argv){ std::cout << "Started!" << std::endl; std::string serializedObject; RequestPackage requestPackageOut; RequestPackage requestPackageIn; requestPackageOut.setPackageId(3); requestPackageIn.setPackageId(0); Serializer::serialize(&serializedObject,&requestPackageOut); Serializer::deserialize(&serializedObject,&requestPackageIn); return 0; } Example 2: int main(int argc, char** argv){ std::cout << "Started!" << std::endl; std::string serializedObject; Package package; RequestPackage requestPackageOut; RequestPackage requestPackageIn; requestPackageOut.setPackageId(3); requestPackageIn.setPackageId(0); Serializer::serialize(&serializedObject,&requestPackageOut); Serializer::deserialize(&serializedObject,&package); return 0; } The Rest: namespace Serializer{ template <typename T> int serialize(std::string *serializedObject, T *package){ int returnValue = 0; std::ostringstream objectOss; boost::archive::xml_oarchive oa(objectOss); try { oa << BOOST_SERIALIZATION_NVP(package); } catch (boost::archive::archive_exception const& ex) { returnValue = 1; } serializedObject->assign(objectOss.str()); return returnValue; }; template <typename T> int deserialize(std::string *serializedObject, T *package){ int returnValue = 0; std::istringstream objectIss(*serializedObject); boost::archive::xml_iarchive ia(objectIss); try { ia >> BOOST_SERIALIZATION_NVP(*package); } catch (boost::archive::archive_exception const& ex) { std::cerr << "Error: " << ex.what() << std::endl; std::cerr.flush(); returnValue = 1; } return returnValue; }; } class RequestPackage : public Package{ private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(Package); ar & BOOST_SERIALIZATION_NVP(requestId); } int requestId; public: int getRequestId() const; void setRequestId(int requestId); }; class Package{ private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & BOOST_SERIALIZATION_NVP(packageID); } int packageID; public: int getPackageId() const; void setPackageId(int packageId); };

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Boost Serialization
by Abraham, Marshel 25 Oct '14

25 Oct '14

I am trying to Serialize a class : StartPeerSessionRequest::StartPeerSessionRequest() { mProtocolVersion = 1*10000 + 14*100 + 4; mSessionFlags = 1; mMaxResponseLength = 0; mMake = "MyMake"; mModel = "MyModel"; mSerialNumber = "10000"; mTrackDelay = 0; mHeadUnitModel = "Headunit"; mCarModelYear = "2014"; mVin = "1234567980"; mVehicleMileage = 1000; mShoutFormat = 3; mNotificationInterval = 1; } template <class Archive> void StartPeerSessionRequest::serialize(Archive &ar, const unsigned int version) { ar & mProtocolVersion; ar & mSessionFlags; ar & mMaxResponseLength; ar & mMake; ar & mModel; ar & mSerialNumber; ar & mTrackDelay; ar & mHeadUnitModel; ar & mCarModelYear; ar & mVin; ar & mVehicleMileage; ar & mShoutFormat; ar & mNotificationInterval; } void StartPeerSessionRequest::save() { boost::archive::binary_oarchive oa(serlreq, boost::archive::no_header); oa << (*this); /*cout<<"\n binary_oarchive :"<<serlreq.size();*/ boost::archive::text_oarchive ota(serializedRequest, boost::archive::no_header); ota<<(*this); cout<<"\n text_oarchive :"<<serializedRequest.str()<<"size :"<<serializedRequest.str().size(); } serializedRequest.str.size() provides me a length of 87 actually it should provide me 65 bytes.( I ve counted u can figure that out from the constructor ) I suspect it is appending lengths in between. I have tried using text_archive also it doesnt work. What I need is to just plain serialize class members as it is. I guess i need to use some traits or wrappers, or boost::serialization::binary_object Please let me know Thanks Regards Marshel Abraham 3097146

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"event-driven" async-receive
by Alexander Carôt 25 Oct '14

25 Oct '14

Hello all, I have question regarding the async_receive_from – operation (using UDP): Right now I have a thread, which triggers the receive call in constant intervals. This works allright if the sender sends data in the same interval or larger intervals. However, if the send intervals are (much) smaller (or if multiple senders exist) the receive-operation is not triggered often enough. Eventually I’d like the receiving socket to behave in an „event-driven “ manner – so, whenever data is there the receive-handler should be invoked. I used to work with Qt, which works this way (via signals/slots) but since I moved to boost I wonder how I can reproduce this behavior. Can anyone tell how to approach this ? Thanks in advance, best Alex

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Applying Boost Phoenix to infinite sequence
by Aaron Levy 24 Oct '14

24 Oct '14

Is there a way to use Boost Phoenix to define an infinite sequence and evaluate specific terms of it, compute partial sums, etc? I am looking for pointers to specific libraries or examples. -- Aaron Levy aaron.levy(a)yandex.com

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