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Re: [Boost-users] bgl - add_vertex during breadth first
by Abebaw Wubshet 06 Sep '05

06 Sep '05

Hi Jeremy, Many thanks for the response. I was hoping I could add vertices inside the algorithm visitor based on some conditions and these same conditions will be applied when the newly added vertices are visited by calling the algorithm only once (a kind of recursive effect). Now it seems that I have to call the algorithm many times and introduce some sort of my own implementation of colour or add a property to each vertex which flags whether it is already expanded or not. Is there any better idea? Cheers, Abebaw > Message: 5 > Date: Mon, 5 Sep 2005 17:19:21 -0500 > From: Jeremy Siek <jeremy.siek(a)gmail.com> > Subject: Re: [Boost-users] bgl - add_vertex during breadth first > search > To: boost-users(a)lists.boost.org > Message-ID: <BE018FBF-735B-4948-8B2A-66793695F214(a)gmail.com> > Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed > > Hi Abebaw, > > Adding vertices and edges is a dangerous thing to do inside an > algorithm visitor. This is because doing that invalidates > iterators that the algorithm is using. Also, the algorithm > creates a mapping from vertices to colors (to mark > which vertices have been processed), and adding vertices > will mess up that mapping. Can you just record that > you want to add vertices and do it after the BFS? > > Cheers, > Jeremy > > On Sep 4, 2005, at 7:43 AM, Abebaw Wubshet wrote: > > Hi all, > > > > I have started using the boost graph library recently. I want to > > add vertices > > and edges to a graph through an algorithm visitor. I chose the > > 'discover_vertex' > > event and added some code to add a vertex/edge. But the compiler > > could not > > determine the apporpriate the matching add_vertex/add_edge > > function. I tried > > fully specifiying the template arguments with no success. (I am > > using gcc 3.3.1 > > on SuSE Linux.) > > > > I tried another alternative which does not work either. I created a > > pointer to a > > graph object which points to my graph insided the > > 'discover_vertex'. But then I > > ended up having a run time error after the vertex is added. > > > > Many thanks, > > Abebaw Wubshet > > > > > > Here is a sample code > > / > > ********************************************************************** > > **/ > > #include <boost/config.hpp> > > #include <iostream> > > #include <boost/graph/adjacency_list.hpp> > > #include <boost/graph/breadth_first_search.hpp> > > #include <boost/shared_ptr.hpp> > > > > using namespace boost; > > > > class VertexProperties > > { > > public: > > std::string _name; > > VertexProperties () {} > > VertexProperties (std::string name) : _name(name) {} > > }; > > > > //OPTION ONE > > class bfs_extend_graph1 : public default_bfs_visitor > > { > > public: > > template<typename Vertex, typename Graph> > > void discover_vertex (Vertex v, Graph& g) > > { > > std::cout<<"\ndiscover"; > > Vertex v_new; > > //the compile gets confused here !!!!! > > v_new = add_vertex(VertexProperties("C"),g); > > add_edge(v,v_new,g); > > } > > }; > > > > //OPTION TWO > > class bfs_extend_graph2 : public default_bfs_visitor > > { > > public: > > template<typename Vertex, typename Graph> > > void discover_vertex (Vertex v, Graph& g) > > { > > std::cout<<"\ndiscover"; > > Vertex v_new; > > typedef adjacency_list< vecS, vecS, directedS, > > VertexProperties> > > graph_t; > > //a pointer to > > shared_ptr<graph_t> ptr_g; > > *ptr_g = g; //reference to the actual graph > > v_new = add_vertex(VertexProperties("C"),*ptr_g); > > add_edge(v,v_new,*ptr_g); > > } > > }; > > > > > > int main() > > { > > typedef adjacency_list< vecS, vecS, directedS, > > VertexProperties> graph_t; > > typedef graph_traits<graph_t>::vertex_descriptor Vertex; > > typedef graph_traits<graph_t>::vertex_iterator vertex_iterator; > > typedef property_map<graph_t,std::string > > VertexProperties::*>::type VP_map_t; > > > > graph_t g; > > Vertex v1,v2; > > > > v1 = add_vertex(VertexProperties("A"),g); > > v2 = add_vertex(VertexProperties("B"),g); > > add_edge(v1,v2,g); > > > > //get the VP map > > VP_map_t VP_map = get(&VertexProperties::_name,g); > > > > bfs_extend_graph1 bfs_e1; > > breadth_first_search(g,v1,visitor(bfs_e1)); > > > > bfs_extend_graph2 bfs_e2; > > breadth_first_search(g,v1,visitor(bfs_e2)); > > > > //check if everything is okay > > std::pair<vertex_iterator, vertex_iterator> vp; > > std::cout<<std::endl<<"vertices : "; > > for ( vp = vertices(g); vp.first != vp.second; ++vp.first) > > { > > VertexProperties vp1 = get(VP_map,*vp.first); > > std::cout<<"\t"<<vp1._name; > > } > > > > return 0; > > } > > > > / > > ********************************************************************** > > **/

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[program_options] VC6 compile error 'illegal pure syntax, must be "=0"'
by Gottenbos, Hennie 06 Sep '05

06 Sep '05

Hi All, I am having problems using the [program_options] library from Boost 1.33. Using this simple program: #include <boost/program_options.hpp> int main(int argc, char* argv[]) { return 0; } I get compile errors like: options_description.hpp(156) : error C2258: illegal pure syntax, must be '= 0' options_description.hpp(156) : error C2252: 'm_default_line_length' : pure specifier can only be specified for functions options_description.hpp(159) : error C2065: 'm_default_line_length' : undeclared identifier This is the first time I'm using Boost. I have successfully developed a program that uses boost::filesystem but I have funny feeling this is a compiler limitation which means I can not use [program_options] on VC6. Can anyone confirm this so I can forget about program_options? Thanks! Hennie.

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Passing template class name without type arguments
by Ovanes Markarian 06 Sep '05

06 Sep '05

Hello, I have a problem. I would like to use standart C++ <functional> function wrappers, but have a problem. At least in MS VC 7.0 a binary_function derivate (like plus) is defined: template<class Type> struct plus : public binary_function <Type, Type, Type> { Type operator()( const Type& _Left, const Type& _Right ) const; }; So if I am goint to add int and double value I will get int back. How can find a work around? First I was thinking about smth like: template<class _Arg1, class _Arg2> struct _ResultType { //some general implementation like typedef typename _Arg1 result_type; }; //specializations like: template<> struct _ResultType<long, double> { typedef double result_type; }; template<class _BinaryFct, class _ResultType> struct Expression { typedef typename _ResultType::result_type result_t; typedef typename _BinaryFct<result_t> binary_fct; //other definitions etc... }; somewhere in the code: #include <functional> Expression<std::plus, _ResultType<long, double> > myExpr; A C++ compiler awaits a real type which causes an error. How else can I change the type of plus<long> to plus<double>. Probably I could write smth like this: typedef std::plus<_ResultType<long, double> > myBinaryFunction; Expression<myBinaryFunction> myExpr; But somehow I don't like it, since the _ResultType class will contain more information as simple result_type. And I will need to pass it twice like: typedef std::plus<_ResultType<long, double> > myBinaryFunction; Expression<myBinaryFunction, _ResultType<long, double> > myExpr; This make the code not very readable... Is there any way using boost to overcome this? With Kind Regards, Ovanes Markarian

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Cannot find a symbol in boost_thread-mt.dll
by Anatoli Sakhnik 06 Sep '05

06 Sep '05

Hi, boost users! I've just tried to execute the simplest boost::thread program, compiled by vc7_1 under multi threaded dll environment. It failed to resolve a symbol in the boost_thead-mt.dll (see the attach). Why? Is it possible to use linked dynamically boost::thread library now? Info: boost version is latest CVS, compiled with --layout=system. No error occurs after gcc-3.4. The program's source: #define BOOST_ALL_NO_LIB #include <boost/thread.hpp> void f() {} int main(int argc, char* argv[]) { boost::thread(f).join(); return 0; } -- Anatoli Sakhnik

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problem with serialization (got my example)
by Benjamin Lau 06 Sep '05

06 Sep '05

Here is my short [kind of?] example. If it is too long, sorry, but I felt that I had to populate my vector with somewhat substantial vector. Also, in my previous post, I said that the other types that class Builder serialized only serialized std::string and booleans, but they also serialize std::vector<std::string>. I don't think it would make any difference since they are all either primitive types or types defined by the standard, but just to clarify. boost_serialization_test.hpp: #ifndef DATA_CLASSES_H #define DATA_CLASSES_H #include <fstream> #include <string> #include <vector> #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/shared_ptr.hpp> class Program { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & sources; ar & target; ar & indent; ar & buildVars; ar & buildVarsValues; } public: Program() : className("Program") { } std::string sources; std::string target; bool indent; std::vector<std::string> buildVars; std::vector<std::string> buildVarsValues; std::string className; }; class Object { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & sources; ar & target; ar & indent; ar & buildVars; ar & buildVarsValues; } public: Object() : className("Object") { } std::string className; std::string sources; std::string target; bool indent; std::vector<std::string> buildVars; std::vector<std::string> buildVarsValues; }; class Java { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & srcDir; ar & classDir; ar & indent; } public: Java() : className("Java") { } std::string className; std::string srcDir; std::string classDir; bool indent; }; class Comment { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & content; } public: std::string content; }; class Print { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & content; ar & indent; } public: Print() : className("Print") { } std::string className; std::string content; bool indent; }; class Variable { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & name; ar & content; ar & indent; } public: Variable() : className("Variable") { } std::string className; std::string name; std::string content; bool indent; }; class Library { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & sources; ar & target; ar & indent; ar & buildVars; ar & buildVarsValues; } public: Library() : className("Library") { } std::string className; std::string sources; std::string target; bool indent; std::vector<std::string> buildVars; std::vector<std::string> buildVarsValues; }; class SharedLibrary { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & sources; ar & target; ar & indent; ar & buildVars; ar & buildVarsValues; } public: SharedLibrary() : className("SharedLibrary") { } std::string className; std::string sources; std::string target; bool indent; std::vector<std::string> buildVars; std::vector<std::string> buildVarsValues; }; class Node { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & nodes; ar & file; ar & dir; ar & content; ar & indent; ar & name; } public: Node() : className("Node") { } std::string className; std::string nodes; std::string file; std::string dir; std::string content; bool indent; std::string name; }; class Import { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & import; } public: Import() : className("Import") { } std::string className; std::string import; }; class Code { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & code; ar & indent; } public: Code() : className("Code") { } std::string className; std::string code; bool indent; }; class SourceSignatures { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & indent; ar & type; } public: SourceSignatures() : className("SourceSignatures") { } std::string className; bool indent; std::string type; }; class TargetSignatures { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & indent; ar & type; } public: TargetSignatures() : className("TargetSignatures") { } std::string className; bool indent; std::string type; }; class SetOption { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & indent; ar & option; ar & value; } public: SetOption() : className("SetOption") { } std::string className; bool indent; std::string option; std::string value; }; class Ignore { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & indent; ar & target; ar & file; } public: Ignore() : className("Ignore") { } std::string className; bool indent; std::string target; std::string file; }; class Depend { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & indent; ar & target; ar & file; } public: Depend() : className("Depend") { } std::string className; bool indent; std::string target; std::string file; }; class EnvironmentVariable { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & indent; ar & name; ar & buildVars; ar & buildVarsValues; } public: EnvironmentVariable() : className("EnvironmentVariable") { } std::string className; bool indent; std::string name; std::vector<std::string> buildVars; std::vector<std::string> buildVarsValues; }; class Builder { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & type; switch(type) { case 0: ar & program; break; case 1: ar & object; break; case 2: ar & java; break; case 3: ar & comment; break; case 4: ar & print; break; case 5: ar & variable; break; case 6: ar & library; break; case 7: ar & sharedLibrary; break; case 8: ar & node; break; case 9: ar & import; break; case 10: ar & code; break; case 11: ar & sourceSignatures; break; case 12: ar & targetSignatures; break; case 13: ar & setOption; break; case 14: ar & ignore; break; case 15: ar & depend; break; case 16: ar & environmentVariable; break; } } public: boost::shared_ptr<Program> program; boost::shared_ptr<Object> object; boost::shared_ptr<Java> java; boost::shared_ptr<Comment> comment; boost::shared_ptr<Print> print; boost::shared_ptr<Variable> variable; boost::shared_ptr<Library> library; boost::shared_ptr<SharedLibrary> sharedLibrary; boost::shared_ptr<Node> node; boost::shared_ptr<Import> import; boost::shared_ptr<Code> code; boost::shared_ptr<SourceSignatures> sourceSignatures; boost::shared_ptr<TargetSignatures> targetSignatures; boost::shared_ptr<SetOption> setOption; boost::shared_ptr<Ignore> ignore; boost::shared_ptr<Depend> depend; boost::shared_ptr<EnvironmentVariable> environmentVariable; int type; }; /* BOOST_CLASS_TRACKING(Program, boost::serialization::track_never) BOOST_CLASS_TRACKING(Object, boost::serialization::track_never) BOOST_CLASS_TRACKING(Java, boost::serialization::track_never) BOOST_CLASS_TRACKING(Comment, boost::serialization::track_never) BOOST_CLASS_TRACKING(Print, boost::serialization::track_never) BOOST_CLASS_TRACKING(Variable, boost::serialization::track_never) BOOST_CLASS_TRACKING(Library, boost::serialization::track_never) BOOST_CLASS_TRACKING(SharedLibrary, boost::serialization::track_never) BOOST_CLASS_TRACKING(Node, boost::serialization::track_never) BOOST_CLASS_TRACKING(Import, boost::serialization::track_never) BOOST_CLASS_TRACKING(Code, boost::serialization::track_never) BOOST_CLASS_TRACKING(SourceSignatures, boost::serialization::track_never) BOOST_CLASS_TRACKING(TargetSignatures, boost::serialization::track_never) BOOST_CLASS_TRACKING(SetOption, boost::serialization::track_never) BOOST_CLASS_TRACKING(Ignore, boost::serialization::track_never) BOOST_CLASS_TRACKING(Depend, boost::serialization::track_never) BOOST_CLASS_TRACKING(EnvironmentVariable, boost::serialization::track_never) BOOST_CLASS_TRACKING(Builder, boost::serialization::track_never)*/ #endif boost_serialization_test.cpp: #include "boost_serialization_test.hpp" int main() { std::ofstream fout("file"); boost::archive::text_oarchive fout_ar(fout); std::vector<Builder> data; Builder *builder = new Builder[10]; for(int i = 0; i < 10; i++) { builder[i].type = i; switch(i) { case 0: builder[i].program->sources = "bshfdvhjvcds"; break; case 1: builder[i].object->sources = "bshfdvhjvcds"; break; case 2: builder[i].java->srcDir = "bshfdvhjvcds"; break; case 3: builder[i].comment->content = "bshfdvhjvcds"; break; case 4: builder[i].print->content = "bshfdvhjvcds"; break; case 5: builder[i].variable->content = "bshfdvhjvcds"; break; case 6: builder[i].library->sources = "bshfdvhjvcds"; break; case 7: builder[i].sharedLibrary->sources = "bshfdvhjvcds"; break; case 8: builder[i].node->content = "bshfdvhjvcds"; break; case 9: builder[i].import->import = "bshfdvhjvcds"; break; case 10: builder[i].code->code = "bshfdvhjvcds"; break; case 11: builder[i].sourceSignatures->type = "jsdbifbviugvdbuyvf"; break; case 12: builder[i].targetSignatures->type = "jsdbifbviugvdbuyvf"; break; case 13: builder[i].setOption->option = "jsdbifbviugvdbuyvf"; break; case 14: builder[i].ignore->target = "jsdbifbviugvdbuyvf"; break; case 15: builder[i].depend->target = "jsdbifbviugvdbuyvf"; break; case 16: builder[i].environmentVariable->name = "vhdbfubvugvsdfuvy"; break; } } for(int i = 0; i < 10; i++) { data.push_back(builder[i]); } fout_ar << data; } Thanks a lot. Benjamin Lau P/s By the way, the /**/ around the BOOST_CLASS_TRACKING were from an earlier attempt to correct the problem, but with or without the macros, the same error messages appear.

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bgl - add_vertex during breadth first search
by Abebaw Wubshet 05 Sep '05

05 Sep '05

Hi all, I have started using the boost graph library recently. I want to add vertices and edges to a graph through an algorithm visitor. I chose the 'discover_vertex' event and added some code to add a vertex/edge. But the compiler could not determine the apporpriate the matching add_vertex/add_edge function. I tried fully specifiying the template arguments with no success. (I am using gcc 3.3.1 on SuSE Linux.) I tried another alternative which does not work either. I created a pointer to a graph object which points to my graph insided the 'discover_vertex'. But then I ended up having a run time error after the vertex is added. Many thanks, Abebaw Wubshet Here is a sample code /************************************************************************/ #include <boost/config.hpp> #include <iostream> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/breadth_first_search.hpp> #include <boost/shared_ptr.hpp> using namespace boost; class VertexProperties { public: std::string _name; VertexProperties () {} VertexProperties (std::string name) : _name(name) {} }; //OPTION ONE class bfs_extend_graph1 : public default_bfs_visitor { public: template<typename Vertex, typename Graph> void discover_vertex (Vertex v, Graph& g) { std::cout<<"\ndiscover"; Vertex v_new; //the compile gets confused here !!!!! v_new = add_vertex(VertexProperties("C"),g); add_edge(v,v_new,g); } }; //OPTION TWO class bfs_extend_graph2 : public default_bfs_visitor { public: template<typename Vertex, typename Graph> void discover_vertex (Vertex v, Graph& g) { std::cout<<"\ndiscover"; Vertex v_new; typedef adjacency_list< vecS, vecS, directedS, VertexProperties> graph_t; //a pointer to shared_ptr<graph_t> ptr_g; *ptr_g = g; //reference to the actual graph v_new = add_vertex(VertexProperties("C"),*ptr_g); add_edge(v,v_new,*ptr_g); } }; int main() { typedef adjacency_list< vecS, vecS, directedS, VertexProperties> graph_t; typedef graph_traits<graph_t>::vertex_descriptor Vertex; typedef graph_traits<graph_t>::vertex_iterator vertex_iterator; typedef property_map<graph_t,std::string VertexProperties::*>::type VP_map_t; graph_t g; Vertex v1,v2; v1 = add_vertex(VertexProperties("A"),g); v2 = add_vertex(VertexProperties("B"),g); add_edge(v1,v2,g); //get the VP map VP_map_t VP_map = get(&VertexProperties::_name,g); bfs_extend_graph1 bfs_e1; breadth_first_search(g,v1,visitor(bfs_e1)); bfs_extend_graph2 bfs_e2; breadth_first_search(g,v1,visitor(bfs_e2)); //check if everything is okay std::pair<vertex_iterator, vertex_iterator> vp; std::cout<<std::endl<<"vertices : "; for ( vp = vertices(g); vp.first != vp.second; ++vp.first) { VertexProperties vp1 = get(VP_map,*vp.first); std::cout<<"\t"<<vp1._name; } return 0; } /************************************************************************/

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date_time io bug in 1.33?
by Serge Skorokhodov 05 Sep '05

05 Sep '05

Hi, The following code looks pretty suspicious to me: extern const wchar_t* pts; // pts = L"2004071" std::wistringstream wiss(pts); wtime_input_facet* wtif = new wtime_input_facet; wtif->set_iso_format(); wiss.imbue(std::locale(std::locale::classic(), wtif)); ptime pt; wiss >> pt; std::string dbgs = to_iso_string(pt); // dbgs == "20040711T000000" Seems to be a bug? TIA -- Serge

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problem with serialization
by Benjamin Lau 05 Sep '05

05 Sep '05

Hello all, I'm new to the serialization library and new to Boost in general and as many newbies do, have some problems using them. I'm trying to serialize an object in my program but the compiler keeps on reporting errors about the types. Specifically, it trips on the BOOST_STATIC_ASSERT(check_tracking<T>::value); in oserializer.hpp in include/archive/detail. The exact compiler message is: C:/Boost/include/boost-1_33/boost/archive/detail/oserializer.hpp: In function `void boost::archive::save(Archive&, T&) [with Archive = boost::archive::text_oarchive, T = std::vector<Builder, std::allocator<Builder> >]': C:/Boost/include/boost-1_33/boost/archive/basic_text_oarchive.hpp:78: instantiated from `void boost::archive::basic_text_oarchive<Archive>::save_override(T&, int) [with T = std::vector<Builder, std::allocator<Builder> >, Archive = boost::archive::text_oarchive]' C:/Boost/include/boost-1_33/boost/archive/detail/interface_oarchive.hpp:85: instantiated from `Archive& boost::archive::detail::interface_oarchive<Archive>::operator<<(T&) [with T = std::vector<Builder, std::allocator<Builder> >, Archive = boost::archive::text_oarchive]' sconbuild.cpp:557: instantiated from here C:/Boost/include/boost-1_33/boost/archive/detail/oserializer.hpp:566: error: incomplete type `boost::STATIC_ASSERTION_FAILURE< false>' used in nested name specifier C:/Boost/include/boost-1_33/boost/archive/detail/oserializer.hpp:566: error: size of array has non-integral type `<type error>' Basically, I'm trying to serialize a std::vector<Builder>. Builder is a class that employs selective serialization, it only serializes certain members depending on what type this Builder is. I use a switch-case statement for that: switch(type) { case 0: ar & program; break; case 1: ar & object; break; case 2: ar & java; break; case 3: ar & comment; break; case 4: ar & print; break; case 5: ar & variable; break; case 6: ar & library; break; case 7: ar & sharedLibrary; break; case 8: ar & node; break; case 9: ar & import; break; case 10: ar & code; break; case 11: ar & sourceSignatures; break; case 12: ar & targetSignatures; break; case 13: ar & setOption; break; case 14: ar & ignore; break; case 15: ar & depend; break; case 16: ar & environmentVariable; break; } These members I am serializing are shared pointers of class types, and each of these class types has a serialize member function that serializes primitive/standard library data types, i.e.: template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & indent; //std::string ar & target; // std::string ar & file; //std::string } That said, ALL of my serializations in these subtypes, i.e. ar & environmentVariable all serialize booleans and std::string. Here is a summary of what I am doing: 1. serialize a vector of Builder objects 2. Builder objects have their shared_ptr selectively serialized 3. The types used to instantiate shared_ptr in my program all serialize booleans and/or std::string I read up on modifying object tracking to track_never but it still doesn't work. Is there something I am doing wrong here? Thank you Benjamin Lau (Windows XP SP2, MinGW with no STLPort) P/s If there is insufficient information, or it is not clear, my most sincere apologies, because the last time I posted whole code on a mailing list, the mailing list program rejected my post. I'll try and get a program that can replicate this behaviour, but so far nothing seems to replicate this behaviour. Thanks you.

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VC++2005 B2: x64 issues
by Cory Nelson 05 Sep '05

05 Sep '05

I get a bunch of warnings from boost filesystem about abi_prefix/suffix "alignment changed after including header, may be due to missing #pragma pack(pop)". But I'm getting one linker error from boost thread: libboost_thread-vc80-mt-s-1_33.lib(once.obj) : error LNK2001: unresolved external symbol _InterlockedCompareExchange I changed compare_exchange's body in once.cpp from: ice_wrapper(&InterlockedCompareExchange, dest, exch, cmp); to: return InterlockedCompareExchange(dest, exch, cmp); and it worked. -- Cory Nelson http://www.int64.org

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Boost serialization storage question
by Leon Mergen 04 Sep '05

04 Sep '05

Hello, I wondered how the Boost.Serialization library determines how many bytes to read from an input stream to "fill" a class with data. That is, does it read an entire input stream until the end of the stream and use that as the data to fill a class with, or does it perform a sizeof(class) and read that from the stream ? If it is the latter, then out of curiosity, how does it determine the size of an object with different class versions ( so if an object version 1 has been saved and then tries to load version 2 ) ? Does it write some sort of object size at the beginning of the file ? If it reads the entire stream until the end, what would be a good approach to save multiple objects in a single file, and be able to read just a few objects out of the file ? Thanks in advance for any responses. Regards, Leon Mergen

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