February 2008 - Boost-users - lists.preview.boost.org

gzip_compressor cannot be flushed and closed properly
by Mengda Wu 27 Feb '08

27 Feb '08

Hi, I have a code block trying to output a series of gzip files. I wish to have all the files flushed after the block. But the files can only be flushed after exiting the whole program. The files still have zero size after I try to close them. I am using std::vector to store all the pointers to boost filtering_ostream. Can you help? //Open iostreams char filename[20]; std::vector<boost::iostreams::filtering_ostream *> os_vector; for(i=0; i<4; i++) { sprintf(filename, "file_%d.gz", i ); std::ofstream *of = new std::ofstream(filename, std::ios_base::binary); boost::iostreams::filtering_ostream* os = new boost::iostreams::filtering_ostream; os->push(boost::iostreams::gzip_compressor()); os->push(*of); os_vector->push_back(os); } //Output something for(i=0; i<4; i++) { boost::iostreams::filtering_ostream* os = os_vector[i]; os<<"Output something here" << std::endl; } //Close streams for(i=0; i<4; i++) { boost::iostreams::filtering_ostream* os = os_vector[i]; os->strict_sync(); os->pop(); os->reset(); } Thanks, Mengda

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[interprocess] Many-to-many communication
by Boris 27 Feb '08

27 Feb '08

I have an application which needs to communicate with several other applications on the same machine. I thought to use message queues but quickly ran into a problem: Either I create as many threads as there are message queues which all block and wait for incoming data or I constantly poll all message queues. The later should be easily possible with try_receive(). However it doesn't sound like a good idea to poll continuously? And I assume integrating the message queue somehow into Boost.Asio is not something easily possible? Thus for many-to-many communication shared memory is probably the way to go? Boris

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BGL: Bug in depth_first_search
by Christian Sturz 27 Feb '08

27 Feb '08

Hi, as it seems I've found a bug in the depth_first_search algorithm. I want to use it with my own ColorMap and a start vertex. Here is the code taken from http://www.boost.org/libs/graph/example/dfs-example.cpp with some slight modifications: ------------------------------------ include <boost/graph/adjacency_list.hpp> #include <boost/graph/depth_first_search.hpp> #include <boost/pending/integer_range.hpp> #include <boost/pending/indirect_cmp.hpp> #include <iostream> using namespace boost; template < typename TimeMap > class dfs_time_visitor:public default_dfs_visitor { typedef typename property_traits < TimeMap >::value_type T; public: dfs_time_visitor(TimeMap dmap, TimeMap fmap, T & t) : m_dtimemap(dmap), m_ftimemap(fmap), m_time(t) { } template < typename Vertex, typename Graph > void discover_vertex(Vertex u, const Graph & g) const { put(m_dtimemap, u, m_time++); } template < typename Vertex, typename Graph > void finish_vertex(Vertex u, const Graph & g) const { put(m_ftimemap, u, m_time++); } TimeMap m_dtimemap; TimeMap m_ftimemap; T & m_time; }; int main() { // Select the graph type we wish to use typedef adjacency_list < vecS, vecS, directedS > graph_t; typedef graph_traits < graph_t >::vertices_size_type size_type; // Set up the vertex names enum { u, v, w, x, y, z, N }; char name[] = { 'u', 'v', 'w', 'x', 'y', 'z' }; // Specify the edges in the graph typedef std::pair < int, int >E; E edge_array[] = { E(u, v), E(u, x), E(x, v), E(y, x), E(v, y), E(w, y), E(w, z), E(z, z) }; #if defined(BOOST_MSVC) && BOOST_MSVC <= 1300 graph_t g(N); for (std::size_t j = 0; j < sizeof(edge_array) / sizeof(E); ++j) add_edge(edge_array[j].first, edge_array[j].second, g); #else graph_t g(edge_array, edge_array + sizeof(edge_array) / sizeof(E), N); #endif // Typedefs typedef boost::graph_traits < graph_t >::vertex_descriptor Vertex; Vertex root = source( edge_array[2],g ); typedef size_type* Iiter; // discover time and finish time properties std::vector < size_type > dtime(num_vertices(g)); std::vector < size_type > ftime(num_vertices(g)); size_type t = 0; dfs_time_visitor < size_type * >vis(&dtime[0], &ftime[0], t); std::vector<default_color_type> color(num_vertices( g ) ); depth_first_search(g, visitor(vis), &color[0], root ); return 0; } ------------------------------------ So, I've added a ColorMap and a start vertex as 3. and 4. argument to "depth_first_search". This code can't be compiled with the gcc on a Debian Etch machine. These are the compiler errors: dfs.cc: In function `int main()': dfs.cc:47: warning: unused variable 'name' /usr/include/boost/graph/depth_first_search.hpp: In function `void boost::depth_first_search(const VertexListGraph&, DFSVisitor, ColorMap, typename boost::graph_traits<G>::vertex_descriptor) [with VertexListGraph = main()::graph_t, DFSVisitor = boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>, ColorMap = boost::default_color_type*]': dfs.cc:76: instantiated from here /usr/include/boost/graph/depth_first_search.hpp:197: error: 'struct boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>' has no member named 'initialize_vertex' dfs.cc:76: instantiated from here /usr/include/boost/graph/depth_first_search.hpp:200: error: 'struct boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>' has no member named 'start_vertex' dfs.cc:76: instantiated from here /usr/include/boost/graph/depth_first_search.hpp:207: error: 'struct boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>' has no member named 'start_vertex' /usr/include/boost/graph/depth_first_search.hpp: In function `void boost::detail::depth_first_visit_impl(const IncidenceGraph&, typename boost::graph_traits<G>::vertex_descriptor, DFSVisitor&, ColorMap, TerminatorFunc) [with IncidenceGraph = boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, boost::no_property, boost::no_property, boost::no_property, boost::listS>, DFSVisitor = boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>, ColorMap = boost::default_color_type*, TerminatorFunc = boost::detail::nontruth2]': /usr/include/boost/graph/depth_first_search.hpp:201: instantiated from `void boost::depth_first_search(const VertexListGraph&, DFSVisitor, ColorMap, typename boost::graph_traits<G>::vertex_descriptor) [with VertexListGraph = main()::graph_t, DFSVisitor = boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>, ColorMap = boost::default_color_type*]' dfs.cc:76: instantiated from here /usr/include/boost/graph/depth_first_search.hpp:103: error: 'struct boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>' has no member named 'discover_vertex' /usr/include/boost/graph/depth_first_search.hpp:201: instantiated from `void boost::depth_first_search(const VertexListGraph&, DFSVisitor, ColorMap, typename boost::graph_traits<G>::vertex_descriptor) [with VertexListGraph = main()::graph_t, DFSVisitor = boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>, ColorMap = boost::default_color_type*]' dfs.cc:76: instantiated from here /usr/include/boost/graph/depth_first_search.hpp:120: error: 'struct boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>' has no member named 'examine_edge' /usr/include/boost/graph/depth_first_search.hpp:201: instantiated from `void boost::depth_first_search(const VertexListGraph&, DFSVisitor, ColorMap, typename boost::graph_traits<G>::vertex_descriptor) [with VertexListGraph = main()::graph_t, DFSVisitor = boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>, ColorMap = boost::default_color_type*]' dfs.cc:76: instantiated from here /usr/include/boost/graph/depth_first_search.hpp:123: error: 'struct boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>' has no member named 'tree_edge' /usr/include/boost/graph/depth_first_search.hpp:201: instantiated from `void boost::depth_first_search(const VertexListGraph&, DFSVisitor, ColorMap, typename boost::graph_traits<G>::vertex_descriptor) [with VertexListGraph = main()::graph_t, DFSVisitor = boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>, ColorMap = boost::default_color_type*]' dfs.cc:76: instantiated from here /usr/include/boost/graph/depth_first_search.hpp:127: error: 'struct boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>' has no member named 'discover_vertex' /usr/include/boost/graph/depth_first_search.hpp:201: instantiated from `void boost::depth_first_search(const VertexListGraph&, DFSVisitor, ColorMap, typename boost::graph_traits<G>::vertex_descriptor) [with VertexListGraph = main()::graph_t, DFSVisitor = boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>, ColorMap = boost::default_color_type*]' dfs.cc:76: instantiated from here /usr/include/boost/graph/depth_first_search.hpp:133: error: 'struct boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>' has no member named 'back_edge' /usr/include/boost/graph/depth_first_search.hpp:201: instantiated from `void boost::depth_first_search(const VertexListGraph&, DFSVisitor, ColorMap, typename boost::graph_traits<G>::vertex_descriptor) [with VertexListGraph = main()::graph_t, DFSVisitor = boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>, ColorMap = boost::default_color_type*]' dfs.cc:76: instantiated from here /usr/include/boost/graph/depth_first_search.hpp:136: error: 'struct boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>' has no member named 'forward_or_cross_edge' /usr/include/boost/graph/depth_first_search.hpp:201: instantiated from `void boost::depth_first_search(const VertexListGraph&, DFSVisitor, ColorMap, typename boost::graph_traits<G>::vertex_descriptor) [with VertexListGraph = main()::graph_t, DFSVisitor = boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>, ColorMap = boost::default_color_type*]' dfs.cc:76: instantiated from here /usr/include/boost/graph/depth_first_search.hpp:141: error: 'struct boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>' has no member named 'finish_vertex' /usr/include/boost/graph/depth_first_search.hpp: In member function `void boost::DFSVisitorConcept<Visitor, Graph>::constraints() [with Visitor = boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>, Graph = main()::graph_t]': /usr/include/boost/concept_check.hpp:48: instantiated from `void boost::function_requires(boost::mpl::identity<T>*) [with Concept = boost::DFSVisitorConcept<boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>, main()::graph_t>]' /usr/include/boost/graph/depth_first_search.hpp:191: instantiated from `void boost::depth_first_search(const VertexListGraph&, DFSVisitor, ColorMap, typename boost::graph_traits<G>::vertex_descriptor) [with VertexListGraph = main()::graph_t, DFSVisitor = boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>, ColorMap = boost::default_color_type*]' dfs.cc:76: instantiated from here /usr/include/boost/graph/depth_first_search.hpp:36: error: 'struct boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>' has no member named 'initialize_vertex' /usr/include/boost/graph/depth_first_search.hpp:37: error: 'struct boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>' has no member named 'start_vertex' /usr/include/boost/graph/depth_first_search.hpp:38: error: 'struct boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>' has no member named 'discover_vertex' /usr/include/boost/graph/depth_first_search.hpp:39: error: 'struct boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>' has no member named 'examine_edge' /usr/include/boost/graph/depth_first_search.hpp:40: error: 'struct boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>' has no member named 'tree_edge' /usr/include/boost/graph/depth_first_search.hpp:41: error: 'struct boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>' has no member named 'back_edge' /usr/include/boost/graph/depth_first_search.hpp:42: error: 'struct boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>' has no member named 'forward_or_cross_edge' /usr/include/boost/graph/depth_first_search.hpp:43: error: 'struct boost::bgl_named_params<dfs_time_visitor<main::size_type*>, boost::graph_visitor_t, boost::no_property>' has no member named 'finish_vertex' So, there seem to be a bug in the algorithm. When calling it as defined in the exampl file from the Boost side without a ColorMap and a vertex, it works fine. Could you verify this and tell me if you can reproduce it? Thank you. Regards, Christian -- GMX startet ShortView.de. Hier findest Du Leute mit Deinen Interessen! Jetzt dabei sein: http://www.shortview.de/?mc=sv_ext_mf@gmx

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[serialization] class template with virtual base
by Richard Crossley 27 Feb '08

27 Feb '08

Hi, I've been searching the archives but am not finding an answer... Is there any way to serialise D<> via a pointer to its base B when the types used to parameterise D<> are not known in advance? i.e. How do I register D<> with the serialisation library? For Example... struct B{ virtual void fn() =0; }; template<typename T> struct D : B{ virtual void fn(){}; }; B* b = new D<char>(); .... anArchive & b; Thanks, Richard.

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Re: [Boost-users] boost::crc32 - visual studio crt - bug?!
by gfsdgadas＠Safe-mail.net 27 Feb '08

27 Feb '08

I do not like the idea of changing my compile flags (I really do like that option for my debug builds!) just because of boost crc32. What about changing the header the request way, marking all casts using &0xFF? I do not see any reason for those safe marks not being introduces into boost crc.

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Boost PP lib
by Hicham Mouline 27 Feb '08

27 Feb '08

hi, in an ealier post, i was helped to write explicit template instantiations as: #define FINH1 (EC)(EP)(AC)(AP) #define FINH2 (C)(D)(E)(F)(G) #define FINH3 (2)(3) #define M(r, product) template class Tree<BOOST_PP_SEQ_ENUM(product)>; BOOST_PP_SEQ_FOR_EACH_PRODUCT(M, (FINH1)(FINH2)(FINH3)) That nicely generated: template class Tree<EC,C,2>; template class Tree<EC,C,3>; template class Tree<EC,D,2>; template class Tree<EC,D,3>; ... what i need now is coupling FINH2 and FINH3 (i don't want their crossproduct) as in: #define FINH1 (EC)(EP)(AC)(AP) #define FINH2 (C,2)(D,2)(E,3)(F,3)(G,3) #define M(r, product) template class Tree<BOOST_PP_SEQ_ENUM(product)>; BOOST_PP_SEQ_FOR_EACH_PRODUCT(M, (FINH1)(FINH2)) But that does't work because the commas in FINH2 are taken as macro arguments which fails... ideas are appreciated... regards,

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Boost Interprocess docs
by Wolfram Stering 27 Feb '08

27 Feb '08

Hello List, if I wanted to read Boost.Interprocess documentation, where would I look for it? I want to evaluate Boost.Interprocess for use in a setuid application with requires a GUI part using a backend (setuid) and a frontend (gui) process. Boost.Interprocess is scheduled to be included in release 1.35, if I remember correctly. thanks for your help, best regards, -wolfi -- Wolfram Stering (Entwicklung) HALE electronic GmbH Eugen-Müller-Straße 18, 5020 Salzburg, Austria Tel: +43 (662) 439011 550 Fax: +43 (662) 439011 9 http://www.hale.at/ Firmenbuchnummer: FN 66801m HG Salzburg -- Scanned by MailScanner.

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circular_buffer iterator problem
by abir basak 27 Feb '08

27 Feb '08

Hi, I have a boost svn trunk checkout (latest one). It seems boost circular_buffer has a iterator problem for converting from non const to const iterator, on visual studio 7.1 (2003) release build only. Can someone check for it ? (It used to work on boost 1.34) for eg, using namespace boost::assign; typedef boost::circular_buffer<int> CB; std::vector<int> v; v+=1,2,3,4,5,6,7,8,9,10,11,12; CB buf(10,v.begin(),v.end()); CB::iterator it = buf.begin(); CB::const_iterator it1 = buf.begin();/// This line doesn't compile on release build only. a second (and little different) question, why boost::assign doesn't work with circular_buffer directly which has 2 iterator construct like most other STL containers ? thanks abir -- Abir Basak, Member IEEE Software Engineer, Read Ink Technologies B. Tech, IIT Kharagpur email: abir(a)abirbasak.com homepage: www.abirbasak.com

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boost::lambda::bind internal object storage
by Zian Smith 27 Feb '08

27 Feb '08

Hello, Can someone explain why I see 5 constructor calls here, but only 4 destructor calls? Is the bind function neglecting to destroy one of the internal copies made or am I missing something? I understand that if I use the "var" function, the problem is eliminated, but I'd still like to figure this out. I'm using boost 1.33.1 -Thanks! //================================= #include <iostream> #include <vector> #include <algorithm> #include "boost/lambda/bind.hpp" using namespace std; using namespace boost::lambda; struct woot { woot() { cout << "woot constr\n"; } woot(const woot& o) { cout << "woot copy-constr\n"; } ~woot() { cout << "woot destr\n"; } }; void do_nothing(const woot& w) { } int main() { woot w; vector<char> v; for_each(v.begin(), v.end(), bind(do_nothing, w)); } //================================= Output: ------- woot constr woot copy-constr woot copy-constr woot copy-constr woot destr woot destr woot copy-constr woot destr woot destr ____________________________________________________________________________________ Never miss a thing. Make Yahoo your home page. http://www.yahoo.com/r/hs

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ASIO ssl::stream read/write_some question.
by Derrick Hathaway 27 Feb '08

27 Feb '08

Could someone please shed some light on ASIO SSL reads and writes for me? The names of the read and write functions for the ssl::stream (read_some and write_some) imply to me that the buffer(s) may not be completely filled/sent with a read/write. Do I need to have some intermediate handler that will begin another async_read/write_some until my buffer is filled/flushed? The documentation doesn't seem to indicate that this is necessary. It makes sense from the example that the reads may not fill the provided buffer before invoking the handler. So it may be necessary to call read_some multiple times until the expected number of bytes is received. But is this also the case with writes, and if so, how do I manage multiple writes if I provide a vector of buffers to be written with and async_write_some? Thanks in advance. Derrick

2 2

boost.serialization question
by Aljaz 27 Feb '08

27 Feb '08

Hello I use boost.serialization for data transfer betwen my server and client applications. The example of serialized data looks like: " 3b22 serialization::archive 4 0 1 2 7 request 1 0 0 1 0 1 2 1 " I've been wondering if there is any way to hide serialization:.archive in the data, maybe replace it with something like 'sa' .. Thanks a lot for help Best regards Aljaz

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Re: [Boost-users] Boost.Test unit testing examples: stale links
by Tim Allison 27 Feb '08

27 Feb '08

To see example 1, use: http://www.boost.org/libs/test/example/unit_test_example_01.cpp The obvious changes are needed for the other examples. (Someone else found these links and posted them at the almost unused forums on SourceForge.) From what I have been able to figure out, the most up to date examples and documentation are found at: http://www.patmedia.net/~rogeeff/html/utf/user-guide.html. I would like to know if you can compile the examples. I can not. I sent an email a week or so ago requesting help compiling the examples with g++. So far, I have not had a response. Tim Allison > ------------------------------ > > Message: 6 > Date: Tue, 26 Feb 2008 22:33:16 +0100 > From: Bram Kuijper <a.l.w.kuijper(a)rug.nl> > Subject: [Boost-users] Boost.Test unit testing examples: stale links > To: boost-users(a)lists.boost.org > Message-ID: <47C4859C.5000302(a)rug.nl> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Hi all, > > I don't know if this is the right place for it, but I wanted to report a > number of stale links on the Boost.Test website. It regards the examples > of the Unit Testing Framework, example 1 to 5 on page > http://www.boost.org/libs/test/doc/examples/index.html > : > > http://www.boost.org/libs/test/doc/examples/unit_test_example1.html > http://www.boost.org/libs/test/doc/examples/unit_test_example2.html > http://www.boost.org/libs/test/doc/examples/unit_test_example3.html > http://www.boost.org/libs/test/doc/examples/unit_test_example4.html > http://www.boost.org/libs/test/doc/examples/unit_test_example5.html > > since I really would like to see some examples of this testing > framework, I wonder if it is possible to have these examples back online? > > thanks, > > Bram Kuijper > >

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[IOStreams] Inconsistency b/w docs and code of stream()
by Nitay Joffe 27 Feb '08

27 Feb '08

Hey guys, I'm working with the boost::iostreams library to create a stream object from a Device class I've implemented. I'm trying to call the constructor that allows setting of the buffer size and it is failing to compile on 64 bit. I used the documenation at http://www.boost.org/libs/iostreams/doc/guide/generic_streams.html#stream The docs say the constructor is of the form: stream(const T& t, std::streamsize buffer_size = default_value, std::streamsize pback_size = default_value); My code to create the stream looks like: MyDevice myDevice(...) MyStream(myDevice, (std::streamsize)500); On a 32 bit machine this works fine, but on a 64 bit one it does not compile. The parameters I'm passing in are not matching up with a constructor in the stream class so it tries to call MyDevice with the wrong set of parameters. I believe the culprit is the file iostreams/detail/push_params.hpp, which defines the buffer and pback size using: #define BOOST_IOSTREAMS_PUSH_PARAMS() \ , int buffer_size = -1 , int pback_size = -1 \ /**/ This macro is then used by stream and friends in their constructor declarations. On 64 bit machines std::streamsize is a long int, so the constructor parameters do not match up and compilation fails. Thanks, -n

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serialization: classes with pimpls
by Noah Roberts 26 Feb '08

26 Feb '08

Any ideas? The only options I can come up with are: 1) break the pimpl idiom by removing the opaqueness or implementing private getter/setter functions for the serialize template. Still get the exception safety of using the pimpl but lose the compile-time decoupling. 2) only implement the serialize function for certain types of archives. This one seems the most interesting actually. 3) write string writers/parsers for serialize to use, which pretty much destroys the whole point of using boost::serialization in the first place. Maybe I'm missing a good option?

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iterator_traits and shared_ptr
by Patrik Jonsson 26 Feb '08

26 Feb '08

Hi, I'm trying to transparently get the type of a shared_ptr or a pod pointer using iterator_traits::value_type. This fails on shared_ptr<T> with the following message: /usr/lib/gcc/x86_64-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/stl_iterator_base_types.h: In instantiation of 'std::iterator_traits<boost::shared_ptr<int> >': crap.cc:5: instantiated from here /usr/lib/gcc/x86_64-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/stl_iterator_base_types.h:129: error: no type named 'iterator_category' in 'class boost::shared_ptr<int>' /usr/lib/gcc/x86_64-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/stl_iterator_base_types.h:131: error: no type named 'difference_type' in 'class boost::shared_ptr<int>' It seems shared_ptr needs difference_type and iterator_category for this to work. Is there another way to accomplish what I'm trying to do? Regards, /Patrik

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[variant] make_recursive_variant containing a variant ?
by Alban Linard 26 Feb '08

26 Feb '08

Hi, i am trying to build a recursive variant containing another variant, as described in the following source code: #include <cstdlib> #include <vector> #include <string> #include <boost/variant.hpp> typedef ::boost::variant < int , bool > first_variant; typedef ::boost::make_recursive_variant < first_variant , ::std::string , ::std::vector< ::boost::recursive_variant_ > >::type second_variant; int main() { first_variant f(true); second_variant s(f); return EXIT_SUCCESS; } It does not compile (g++-4.0 and g++-4.3). It seems that the "first_variant" part of second_variant is not used. Why this behavior ? Is there a workaround ? Thanks, Alban Linard

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Boost.Test unit testing examples: stale links
by Bram Kuijper 26 Feb '08

26 Feb '08

Hi all, I don't know if this is the right place for it, but I wanted to report a number of stale links on the Boost.Test website. It regards the examples of the Unit Testing Framework, example 1 to 5 on page http://www.boost.org/libs/test/doc/examples/index.html : http://www.boost.org/libs/test/doc/examples/unit_test_example1.html http://www.boost.org/libs/test/doc/examples/unit_test_example2.html http://www.boost.org/libs/test/doc/examples/unit_test_example3.html http://www.boost.org/libs/test/doc/examples/unit_test_example4.html http://www.boost.org/libs/test/doc/examples/unit_test_example5.html since I really would like to see some examples of this testing framework, I wonder if it is possible to have these examples back online? thanks, Bram Kuijper

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Re: [Boost-users] boost exceptions on MacOS 10.5
by David Thulson 26 Feb '08

26 Feb '08

Hello, I have had similar problems in OSX 10.5 where exceptions are not caught, but with a different project. We are using CMake. I'm not sure how familiar you are with CMake, but it is a build system that allows you to generate projects for "native" development tools. In OSX, you can create Xcode projects or makefiles. If I use Xcode to build the project, I cannot catch exceptions consistently. If I use makefiles, it works fine. You can see the discussion on the CMake list here: http://www.cmake.org/pipermail/cmake/2008-January/019091.html The compiler flags that are used are significantly different, so that seems like a likely problem. Unfortunately, I have not had time to finish tracking the issue down. I'm not really familiar with building boost so maybe this is obvious, but how are you building it? What compiler flags are you using? David Thulson

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BGL: ColorMap for depth_first_search
by Christian Sturz 26 Feb '08

26 Feb '08

Hi, I've an urgent question on a BGL algorithm. I want to use the depth_first_search algorithm from the Boost Graph Library. However, I've problems with the definition of my own ColorMap. To illustrate this, here is an example (taken from http://www.boost.org/libs/graph/example/dfs-example.cpp) int main() { // Select the graph type we wish to use typedef adjacency_list < vecS, vecS, directedS > graph_t; typedef graph_traits < graph_t >::vertices_size_type size_type; // Set up the vertex names enum { u, v, w, x, y, z, N }; char name[] = { 'u', 'v', 'w', 'x', 'y', 'z' }; // Specify the edges in the graph typedef std::pair < int, int >E; E edge_array[] = { E(u, v), E(u, x), E(x, v), E(y, x), E(v, y), E(w, y), E(w, z), E(z, z) }; graph_t g(edge_array, edge_array + sizeof(edge_array) / sizeof(E), N); // Typedefs typedef boost::graph_traits < graph_t >::vertex_descriptor Vertex; typedef size_type* Iiter; // discover time and finish time properties std::vector < size_type > dtime(num_vertices(g)); std::vector < size_type > ftime(num_vertices(g)); size_type t = 0; dfs_time_visitor < size_type * >vis(&dtime[0], &ftime[0], t); // Some arbitrary vertex as root (start point of DFS) Vertex root = source( edge_array[2],g ); depth_first_search(g, visitor(vis), myColorMap, root ); return 0; } My problem is the definition of "myColorMap" which must be a model of Read/Write Property Map. However, I have no idea how to define a working ColorMap. It would be fully sufficient to take the default color map which is used when DFS is invoked with "depth_first_search(g, visitor(vis));" Do you have an idea how I define a ColorMap that I can use for "myColorMap"? Any help is appreciated. Thank you. Christian -- Psst! Geheimtipp: Online Games kostenlos spielen bei den GMX Free Games! http://games.entertainment.web.de/de/entertainment/games/free

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[noob] I have pointer, ptr_list::release wants iterator
by Szczepan Hołyszewski 26 Feb '08

26 Feb '08

I have a pointer to an object that is in a ptr_list, and I want to "detach" the object from the list without deleting it. Problem: ptr_list::release() wants an iterator, not a pointer. A naive attempt at std::finding the iterator fails because ptr_list's indirection kicks in and std::find ends up wanting to compare values instead of pointers. Luckily my objects aren't equality comparable so I get a compile error instead of an elusive bug. As a workaround I just walk the list with BOOST_FOREACH() but it feels kludgy. Is there a "designed" way to feed a ptr_list an element pointer and milk the corresponding iterator? Is there a direct way do detach an item from ptr_list without deleting it? Did I overlook something obvious? Thanks in advance, Szczepan Holyszewski

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BGL: ColorMap for depth_first_search
by Christian Sturz 25 Feb '08

25 Feb '08

Hi, I want to use the depth_first_search algorithm. Since I need the DFS version where a start vertex is specified, I also have to define a ColorMap. That's the function I want to use: template <class Graph, class DFSVisitor, class ColorMap> void depth_first_search(const Graph& g, DFSVisitor vis, ColorMap color, typename graph_traits<Graph>::vertex_descriptor start) However, I'm not able to define a working ColorMap. Since the map is irrelevant for me, the default ColorMap would be fully sufficient. Could you give me a hint how to create it? And another short question. I want to iterate the graph backwards via DFS. Could I use the "reverse_graph adaptor" with: depth_first_search( boost::make_reverse_graph(G), visitor( vis ) ...)? Regards, Christian -- GMX startet ShortView.de. Hier findest Du Leute mit Deinen Interessen! Jetzt dabei sein: http://www.shortview.de/?mc=sv_ext_mf@gmx

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Linking problem with read_graphviz
by Michaela Kedikova 25 Feb '08

25 Feb '08

Hello, I'm new to boost(I'm working with boost_1_34_1) and I have a problem with read_graphviz. I'm working with MSVC 8. I've already built all external libraries using bjam and link them to my project. I also built libbgl-viz.lib, which contains all the source files in libs/graph/src.(As it was suggested in a thread) But I still have a link-error when I try to compile the graphviz.cpp example. I've searched in the mailing-list for solutions of this problem, but I didn't find anything, which helped me. Now I hope that somebody could give me a hint, what the problem may be. (My suggestion is, whether there is a missing object in a library or there are some difficulties between boost1_34_1 and MSVC 8.0). I post the error message below: 1>test_graphviz.obj : error LNK2019: unresolved external symbol "void __cdecl boost::read_graphviz(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &,class boost::subgraph<class boost::adjacency_list<struct boost::vecS,struct boost::vecS,struct boost::undirectedS,struct boost::property<enum boost::vertex_attribute_t,class std::map<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,struct std::less<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >,class std::allocator<struct std::pair<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const ,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > > > >,struct boost::no_property>,struct boost::property<enum boost::edge_attribute_t,class std::map<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,struct std::less<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >,class std::allocator<struct std::pair<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const ,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > > > >,struct boost::property<enum boost::edge_index_t,int,struct boost::no_property> >,struct boost::property<enum boost::graph_graph_attribute_t,class std::map<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,struct std::less<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >,class std::allocator<struct std::pair<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const ,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > > > >,struct boost::property<enum boost::graph_vertex_attribute_t,class std::map<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,struct std::less<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >,class std::allocator<struct std::pair<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const ,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > > > >,struct boost::property<enum boost::graph_edge_attribute_t,class std::map<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,struct std::less<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >,class std::allocator<struct std::pair<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const ,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > > > >,struct boost::property<enum boost::graph_name_t,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,struct boost::no_property> > > >,struct boost::listS> > &)" (?read_graphviz@boost@@YAXABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@AAV?$subgraph@V?$adjacency_list@UvecS@boost@@U12@UundirectedS@2@U?$property@W4vertex_attribute_t@boost@@V?$map@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V12@U?$less@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@2@V?$allocator@U?$pair@$$CBV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V12@@std@@@2@@std@@Uno_property@2@@2@U?$property@W4edge_attribute_t@boost@@V?$map@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V12@U?$less@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@2@V?$allocator@U?$pair@$$CBV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V12@@std@@@2@@std@@U?$property@W4edge_index_t@boost@@HUno_property@2@@2@@2@U?$property@W4graph_graph_attribute_t@boost@@V?$map@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V12@U?$less@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@ D@2@@std@@@2@V?$allocator@U?$pair@$$CBV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V12@@std@@@2@@std@@U?$property@W4graph_vertex_attribute_t@boost@@V?$map@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V12@U?$less@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@2@V?$allocator@U?$pair@$$CBV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V12@@std@@@2@@std@@U?$property@W4graph_edge_attribute_t@boost@@V?$map@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V12@U?$less@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@2@V?$allocator@U?$pair@$$CBV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V12@@std@@@2@@std@@U?$property@W4graph_name_t@boost@@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@Uno_property@2@@2@@2@@2@@2@UlistS@2@@boost@@@1@@Z) referenced in function _main 1>D:\Mihaela\Projects_Cpp\Test_Boost\Debug\Test_graphviz.exe : fatal error LNK1120: 1 unresolved externals Sorry for my bad english. Thanks in advance, Mishe __________________________________________________________ Sent from Yahoo! Mail. A Smarter Inbox. http://uk.docs.yahoo.com/nowyoucan.html

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betweenness centrality
by ivanballatore＠libero.it 25 Feb '08

25 Feb '08

Hi, i'm an italian developper and i have a question about the function brandes_betweenness_centrality. I would know if it's possbile to run brandes_betweenness_centrality only on a subset of nodes of a graph, because the execution of the function on the entire graph is too long. I want to calculate the betweenness approximation starting from the value computed for this subset of vetexes. Sorry for my english(i'm italian...).

1 0

subgraph with vertex lists
by Boris Lau 25 Feb '08

25 Feb '08

Hello, I'm new to boost and a bit confused about how to choose the vertex list type. My graph has around 50.000, and will be pruned down to roughly 500, so I use clear_vertex and remove_vertex a lot. According to http://www.boost.org/libs/graph/doc/adjacency_list.html, this works well only with VL=listS, otherwise I cannot safely remove vertices. Is that true? Ok, let's assume for now I need to use VL=listS in order to be able to safely remove vertices. How can I use the subgraph adaptor? It seems to require the vertex_index property, so I tried this: typedef subgraph< adjacency_list<listS, listS, undirectedS, property<vertex_index_t, int>, property<edge_index_t, int> > > Graph; which gives me nasty errors. It does make sense, if adding vertex_index to listS does not work. I was surprised by this, because adding edge_index does do the job if I use EL=listS: typedef subgraph< adjacency_list<listS, vecS, undirectedS, property<vertex_index_t, int>, property<edge_index_t, int> > > Graph; So, back to the topic. I need to be able to remove vertices and edges, and I need to use subgraphs. What can I do? Thanks for any help, Boris

1 1

fusion library not in boost 1.34.1?
by Robert Dailey 25 Feb '08

25 Feb '08

Hi, I've been working out of the development branch for boost for a while and I always took for granted that fusion was part of the library. However, after downgrading back to 1.34.1, I notice it isn't in there. Is there a reason for this? How do I go about downloading a version of fusion that will work with 1.34.1? Thanks.

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