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Newbie
by Shan Wijesinghe 22 Feb '16

22 Feb '16

Hi all, I'm a new member to C++ boost and I have a fairly good knowledge in programming in C++. I'm very much excited to join this group and I need directions from the senior members on how to start myself. Please help me here. Thanks in advance. regards, DilSHAN.

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Query on Boost.DLL
by Leo Carreon 21 Feb '16

21 Feb '16

Hi, I have been reading the Boost.DLL documentation. Can a single plugin support multiple API’s? If yes, when the multiple API’s are used at the same time; will there be only one instance of the plugin loaded or will there be multiple instances loaded? Regards, Leo

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Boost.DLL
by Leo Carreon 21 Feb '16

21 Feb '16

Hi, Can anyone please let me know what the status of the Boost.DLL library is? Regards, Leo

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[coroutine] - only std exceptions are caught from coroutines
by Tamas.Ruszkai＠leica-geosystems.com 21 Feb '16

21 Feb '16

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[Interprocess] Communication between x86 and x64 issue
by Toni Neubert 19 Feb '16

19 Feb '16

I want to communicate between different platforms using boost interprocess. I am using vc12 and boost 1.58 on windows 7. My code below is a very simple example, that should work. But it doesn't for communications between different platforms... If I create it in x64 and open in win32, the process stuck at a lock at function try_based_lock in boost/int/sync/detail/common_algorithms.hpp In the other way around: win32 create, x64 open: the process crashes at name_length in segment_manager_helper.hpp while trying to find the name in index (priv_generic_find in segment_manager). #include <iostream> #include <boost/interprocess/managed_shared_memory.hpp> int main() { namespace bip = boost::interprocess; // open in WIN32, create in x64 #ifdef _WIN32 bip::managed_shared_memory msm(bip::open_only, "TestIPC"); #elsif X64 bip::shared_memory_object::remove("TestIPC"); bip::managed_shared_memory msm(bip::create_only, "TestIPC", 4096); msm.construct<uint32_t>("Data")[1](10); #endif // Get Data and print it auto data = msm.find<uint32_t>("Data"); if (data.second == 1) { std::cout << *data.first << std::endl; } std::cin.ignore(); return 0; } Does anybody have experience in this? Thank you in advance!

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Re: [Boost-users] [Serialization] This compiles; but does it work?
by Bjorn Reese 19 Feb '16

19 Feb '16

On 02/19/2016 04:20 AM, Merrill Cornish wrote: > Can anyone tell me if this will work, or do I need to implement the > serialize() function? When you are doing different things for the input and output archives then it is better to split serialization into load and save: #include <boost/filesystem/path.hpp> #include <boost/serialization/split_free.hpp> namespace boost { namespace serialization { template <typename Archive> void serialize(Archive& ar, filesystem::path& p, const unsigned int version) { split_free(ar, p, version); } template<class Archive> void save(Archive & ar, const filesystem::path& p, unsigned int version) { ar << p.string(); } template<class Archive> void load(Archive & ar, filesystem::path& p, unsigned int version) { std::string data; ar >> data; p = data; } }}

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[graph] Search algorithm using quality metric rather than distance
by rleigh＠codelibre.net 19 Feb '16

19 Feb '16

I have an adjacency_list graph (shown in attached dot file). Each edge has an attached "quality metric" as a bundled property. Similar to the dijkstra_shortest_paths algorithm, I'd like to determine the optimal path. However, this algorithm sums the distance along each edge, and finds the shortest path. What I'd like to do is *multiply* the quality metric for each edge in the path, and find the largest one. A perfect path will have a quality metric of 1.0, while suboptimal paths will have values tending towards zero, and the more "bad" edges the smaller the number. I'll likely then look at the number of edges and then select the shortest of the candidates. It seems like a simple algorithm that might already be included, but I just haven't found it yet not knowing its formal name. If anyone has any suggestions, I'd be very grateful. Many thanks, Roger

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[Serialization] This compiles; but does it work?
by Merrill Cornish 19 Feb '16

19 Feb '16

mGraphFile is a data member of type boost:filesystem::path, which isn't (as I understand) handled natively by Boost Serialization. I could define template<class Archive> void serialize(Archive& ar, boost::filesystem::path& p, const unsigned int version); but it is needed in only one place. Below is an excerpt from an inline serialization function that I'm already using. While it has a redundant step not needed for loading and a different redundant step not needed for storing, it would seem to do what I need. (The minor inefficiency of the redundant statements is of no concern here.) ... std::string str = mGraphFile.string(); // redundant if loading ar & BOOST_SERIALIZATION_NVP(str); mGraphFile = str; // redundant if saving ... Can anyone tell me if this will work, or do I need to implement the serialize() function? Merrill Cornish

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boost::msm usage: how to set properties of target states
by spiritwalker 18 Feb '16

18 Feb '16

States in my fsm has different properties. I define a event which will invoke a transition to a target state. I want to set properties of target by event data. My choices are: 1. set properties in the action or guard: but it is still in the source state. I fill not good if i set the target state properties at the time 2. set properties in the target entry: but the value of properties have been calculated in guard on receiving the event so i should recalculated again :( Any one can give me more ideas. Thanks ! -- View this message in context: http://boost.2283326.n4.nabble.com/boost-msm-usage-how-to-set-properties-of… Sent from the Boost - Users mailing list archive at Nabble.com.

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SERIALIZE: Registering derived templete classes serialized via base ptr
by Unger, Jörg 17 Feb '16

17 Feb '16

I'm trying to serialize a derived class via a base ptr using boost serialize. The example to illustrate the problem (without templates) is as follows //****************** Main.cpp ********************** #include <fstream> #include <boost/archive/text_iarchive.hpp> #include <boost/archive/text_oarchive.hpp> #include "Derived.h" int main(int argc, char* argv[]) { std::string fileName = "Out.txt"; Derived myDerived; Base* myBasePtr = &myDerived; //myDerived.foo(); // serialize it as txt std::ofstream ofs(fileName.c_str(), std::ios_base::binary ); boost::archive::text_oarchive ota ( ofs, std::ios::binary ); //ota & boost::serialization::make_nvp(std::string("directly derived").c_str(), myDerived);; ota & boost::serialization::make_nvp(std::string("via base ptr").c_str(), myBasePtr);; return 0; } //*********************************************** //*************** Base.h ************************* #pragma once #include <boost/serialization/access.hpp> #include <boost/serialization/export.hpp> class Base { friend class boost::serialization::access; public: Base(){}; virtual ~Base(){}; template<class Archive> void serialize(Archive & ar, const unsigned int version) {}; }; BOOST_CLASS_EXPORT_KEY(Base) //*********************************************** //**************** Derived.h ********************** #pragma once #include <boost/serialization/access.hpp> #include <boost/serialization/export.hpp> #include "Base.h" class Derived : public Base { friend class boost::serialization::access; public: Derived(){}; void foo(); template<class Archive> void serialize(Archive & ar, const unsigned int version); }; BOOST_CLASS_EXPORT_KEY(Derived) //*********************************************** //**************** Derived.cpp ******************** #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> #include "Derived.h" //Derived::Derived() //{} void Derived::foo() { } // serializes the class template void Derived::serialize(boost::archive::text_oarchive & ar, const unsigned int version); template void Derived::serialize(boost::archive::text_iarchive & ar, const unsigned int version); template<class Archive> void Derived::serialize(Archive & ar, const unsigned int version) { ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(Base); } BOOST_CLASS_EXPORT_IMPLEMENT(Derived) //*********************************************** When compiling the above code and linking the object files, everything works fine. When I combine everything in a library (in this example it is essentially only Derived.o) and link the main file with the library, I get an error what(): unregistered class - derived class not registered or exported The problem seems to be that the registration in the linked library is not activated. The problem is simplified here, because in our implementation, the derived class is essentially a template class that does not have any cpp-files. We have just added another otherwise empty cpp file with the registration of all possible instantiations of the class. There are several possibilities to solve the problem · The macro BOOST_CLASS_EXPORT_IMPLEMENT(Derived) could be moved to the main.cpp. This workaround is not my preferred options, since the registration has to be done in every main file we want to use the library for. · The macro BOOST_CLASS_EXPORT_IMPLEMENT(Derived) could be moved to the Base.cpp (the constructor for the base class has to be implemented in this file as well). This is another option, but this requires the header files of the derived classes to be included in Base.cpp, which is not convenient either. · Serialize one object of the derived class before serialization through the pointer, but that's only a workaround. (see the commented line in Main.cpp) · Call the foo method in Main.cpp. Surprisingly, this does not depend on whether the foo function is implemented in Derived.cpp, but also if it is called in Main.cpp. Surprisingly, if "myDerived.foo();" in Main.cpp is uncommented the program works fine, which is something I do not understand. It seems that the registration is only performed, if one of the functions in this cpp file is actually called, or am I wrong? · Implement the constructor of Derived in Derived.cpp. This approach works fine for the current example (somehow similar to the previous solution). However, in our case, Derived is a template and thus the constructor can't be implemented in the cpp file. · Another option is to always link the main file with the library and the object file Derived.o, but this is also not a convenient option. · Finally, a manual registration with register_type is possible. This could be moved to a separate subroutine that is always called in different main files. What is the recommended way of registering derived template classes that are serialized through a base ptr within a library. Best regards, Jörg F. Unger

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