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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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Compilation problem with date_time and iostream gzip (and bzip2) filters
by tonton 04 Sep '05

04 Sep '05

This simple test fails to compile with gcc 4.0.1 (or 4.0.2, it's the debian unstable version) and boost 1.33.0 if the date_time include is uncommented. Is there any known incompatibility between the two libraries ? #include <boost/iostreams/filtering_stream.hpp> #include <boost/iostreams/filter/gzip.hpp> // #include <boost/date_time/local_time/local_time.hpp> int main() { boost::iostreams::filtering_istream in; in.push(boost::iostreams::gzip_compressor()); return 0; } The full error is attached /usr/include/boost/iostreams/filter/symmetric.hpp: In member function ‘std::streamsize boost::iostreams::symmetric_filter<SymmetricFilter, Alloc>::read(Source&, typename boost::iostreams::char_type_of<T>::type*, std::streamsize) [with Source = boost::iostreams::detail::linked_streambuf<char, std::char_traits<char> >, SymmetricFilter = boost::iostreams::detail::zlib_compressor_impl<std::allocator<char> >, Alloc = std::allocator<char>]’: /usr/include/boost/iostreams/filter/gzip.hpp:199: instantiated from ‘std::streamsize boost::iostreams::basic_gzip_compressor<Alloc>::read(Source&, char*, std::streamsize) [with Source = boost::iostreams::detail::linked_streambuf<char, std::char_traits<char> >, Alloc = std::allocator<char>]’ /usr/include/boost/iostreams/read.hpp:215: instantiated from ‘static std::streamsize boost::iostreams::detail::read_filter_impl<boost::iostreams::multichar_tag>::read(T&, Source&, typename boost::iostreams::char_type_of<T>::type*, std::streamsize) [with T = boost::iostreams::basic_gzip_compressor<std::allocator<char> >, Source = boost::iostreams::detail::linked_streambuf<char, std::char_traits<char> >]’ /usr/include/boost/iostreams/read.hpp:56: instantiated from ‘std::streamsize boost::iostreams::read(T&, Source&, typename boost::iostreams::char_type_of<T>::type*, std::streamsize) [with T = boost::iostreams::basic_gzip_compressor<std::allocator<char> >, Source = boost::iostreams::detail::linked_streambuf<char, std::char_traits<char> >]’ /usr/include/boost/iostreams/detail/adapter/concept_adapter.hpp:247: instantiated from ‘static std::streamsize boost::iostreams::detail::flt_wrapper_impl<boost::iostreams::input>::read(Filter&, Source*, typename boost::iostreams::char_type_of<T>::type*, std::streamsize) [with Filter = boost::iostreams::basic_gzip_compressor<std::allocator<char> >, Source = boost::iostreams::detail::linked_streambuf<char, std::char_traits<char> >]’ /usr/include/boost/iostreams/detail/adapter/concept_adapter.hpp:74: instantiated from ‘std::streamsize boost::iostreams::detail::concept_adapter<T>::read(typename boost::iostreams::char_type_of<T>::type*, std::streamsize, Source*) [with Source = boost::iostreams::detail::linked_streambuf<char, std::char_traits<char> >, T = boost::iostreams::basic_gzip_compressor<std::allocator<char> >]’ /usr/include/boost/iostreams/detail/streambuf/indirect_streambuf.hpp:250: instantiated from ‘typename boost::iostreams::detail::indirect_streambuf<T, Tr, Alloc, Mode>::int_type boost::iostreams::detail::indirect_streambuf<T, Tr, Alloc, Mode>::underflow() [with T = boost::iostreams::basic_gzip_compressor<std::allocator<char> >, Tr = std::char_traits<char>, Alloc = std::allocator<char>, Mode = boost::iostreams::input]’ test.cpp:10: instantiated from here /usr/include/boost/iostreams/filter/symmetric.hpp:112: error: ‘boost::iostreams::symmetric_filter<boost::iostreams::detail::zlib_compressor_impl<std::allocator<char> >, std::allocator<char> >::<anonymous enum>’ is/uses anonymous type /usr/include/boost/iostreams/filter/symmetric.hpp:112: error: trying to instantiate ‘template<class T> struct boost::is_integral’ /usr/include/boost/iostreams/filter/symmetric.hpp:124: error: ‘boost::iostreams::symmetric_filter<boost::iostreams::detail::zlib_compressor_impl<std::allocator<char> >, std::allocator<char> >::<anonymous enum>’ is/uses anonymous type /usr/include/boost/iostreams/filter/symmetric.hpp:124: error: trying to instantiate ‘template<class T> struct boost::is_integral’ /usr/include/boost/iostreams/filter/symmetric.hpp:131: error: ‘boost::iostreams::symmetric_filter<boost::iostreams::detail::zlib_compressor_impl<std::allocator<char> >, std::allocator<char> >::<anonymous enum>’ is/uses anonymous type /usr/include/boost/iostreams/filter/symmetric.hpp:131: error: trying to instantiate ‘template<class T> struct boost::is_integral’

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Renaming boost libraries
by Matt 04 Sep '05

04 Sep '05

Heya Guys, Just wondering if it's possible to rename the boost libraries after they've been built. Specifically, I want to remove the boost version (-1_33) that is appended to all the lib and dll libraries. The reason is twofold; a) our source control system will mark the libs with a label to indicate the version and b) it should make migrating to a new boost version easier. I'm pretty sure it's fine to just physically rename the static libraries but seem to remember that for dynamic libs you can't do that because the matching .lib file indicates which .dll the application should load. Am I mistaken? If not is there any other way to specify that you don't want the boost version appended to the end of the filename? Cheers, Matt

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Re: [Boost-users] Same thing: dynamic bitset as member of struct!?
by Fujinobu Takahashi 04 Sep '05

04 Sep '05

Hello Bronek-san, YATTA! Multi bitsets Works very well. Very helpful suggestion for me and our colleagues. ARIGATOU GOZAIMASU. Fuji On Sat, 03 Sep 2005 22:33:32 +0100 Bronek Kozicki <brok(a)rubikon.pl> wrote: > Hello > > your constructor is incorrectly defined. Following should work: > > #include <iostream> > #include <boost/timer.hpp> > #include <boost/dynamic_bitset.hpp> > using namespace std; > using namespace boost; > > struct multi_bitsets{ > multi_bitsets() : db1(10,1ul), db2(10,2ul) {} > dynamic_bitset<> db1; > dynamic_bitset<> db2; > }; > > int main() > { > multi_bitsets mb1; > cout << "mb1.db1:" << mb1.db1 << endl; > cout << "mb1.db2:" << mb1.db2 << endl; > } > > > Best regards > > > B.

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How to use dynamic bitset as member data of class?
by Fujinobu Takahashi 04 Sep '05

04 Sep '05

Hello again, I enjoy to use the dynamic_bitset for the 1 bit correlation of radio interferometor. Very useful. But how to use the dynamic bitsets as the member data of the class? class multi_bitsets{ const boost::dynamic_bitset<> db1(20,1ul); const boost::dynamic_bitset<> db2(20,1ul); this kind of code always gives me the following errors: $ g++ multi_bitset_test00.cpp multi_bitset_test00.cpp:19: error: expected identifier before numeric constant multi_bitset_test00.cpp:19: error: expected `,' or `...' before numeric constant multi_bitset_test00.cpp:19: error: ISO C++ forbids declaration of `parameter' with no type Please let me know how to use the dynamic bitsets as the member data of the class, thank you. fuji

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[Boost.Python] How is shared_ptr<SubClass> matched with shared_ptr<Base> in signature?
by Nat Goodspeed 03 Sep '05

03 Sep '05

We have a smart_ptr template of our own, sort of cloned from intrusive_ptr. But I'm having trouble with Python code passing subclass objects managed by this smart_ptr to C++ methods accepting smart_ptr<base class>. Consider: class Base: { ... }; class SubClass: public Base { ... }; class Interface { public: void method(smart_ptr<Base> arg) const; }; Of course SubClass* is implicitly convertible to Base*. In C++ code, smart_ptr<SubClass> is even implicitly convertible to smart_ptr<Base>. That is, given the definitions above, this C++ code compiles and runs correctly: Interface worker; smart_ptr<SubClass> objp = new SubClass(); worker.method(objp); We can inform Boost.Python that Base objects -- and, by implication, SubClass as well -- are to be managed using smart_ptr<>. class_<Base, smart_ptr<Base>, boost::noncopyable>("Base", no_init) ... ; class_<SubClass, bases<Base> >("SubClass") ... ; We have many methods that accept smart_ptr<Base> and do appropriately polymorphic things to SubClass and its siblings. However, if a Python caller attempts to pass a SubClass object to a method accepting smart_ptr<Base>: obj = Extension.SubClass() worker = Extension.Interface() worker.method(obj) we get the following runtime error: Boost.Python.ArgumentError: Python argument types in Interface.method(Interface, SubClass) did not match C++ signature: method(class Interface {lvalue}, class smart_ptr<class Base>) That's true for both Boost 1.31 and Boost 1.32. We have not yet tried this with Boost 1.33. We're using MSVC 7.1 on Windows XP Pro. Okay, I know this is our fault, something's wrong with our smart_ptr template definition. I know that because if I recompile with this: #define smart_ptr boost::shared_ptr instead of our own smart_ptr definition, it works just fine! As noted earlier, our smart_ptr is a variant of boost::intrusive_ptr. But it appears that either there's a mysterious requirement on the smart_ptr template that we're not fulfilling, or there's special recognition of boost::shared_ptr and possibly boost::intrusive_ptr in Boost.Python. What must we add to allow Boost.Python to recognize the legal conversion from smart_ptr<SubClass> to smart_ptr<Base> when it does its argument matching? [Your next question is: why not just use one of the Boost smart pointers? Short answer: that's what we WANTED to do! We tried shared_ptr and ran afoul of the second-conversion-from-same-dumb-pointer problem; we tried intrusive_ptr and got completely entangled in new cross-DLL dependencies because intrusive_ptr doesn't deal well with incomplete pointee types. Our smart_ptr is an attempt to trade away both issues, at the cost of a mandatory pointee base class. It almost works, too, except for this baffling bug...] Thanks for your help.

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