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[iterator] unrelated type problem with iterator_facade arrow operator
by Michael Fawcett 23 Mar '09

23 Mar '09

Can someone confirm if the attached code doesn't compile intentionally or if this is a bug? I'm sorry for not posting a minimal example but I couldn't figure out how to reduce the problem. It requires Windows (uses ATL::CAdapt and ATL::CComBSTR) and I've tested using VS 2005 and VS2008. This bug manifests when the Reference type has overloaded the address-of operator to return a type not implicitly convertible to Value * (I believe). Changing lines 324-326 in iterator_facade.hpp from: static type make(Reference x) { return implicit_cast<type>(&x); } to: static type make(Reference x) { return implicit_cast<type>(boost::addressof(x)); } and adding the appropriate include makes the attached code compile. Full error log below: 1>c:\dev\vendor\boost\1.37.0\boost\iterator\iterator_facade.hpp(326) : error C2664: 'boost::implicit_cast' : cannot convert parameter 1 from 'BSTR *' to 'ATL::CComBSTR *' 1> Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast 1> c:\dev\vendor\boost\1.37.0\boost\iterator\iterator_facade.hpp(325) : while compiling class template member function 'ATL::CComBSTR *boost::detail::operator_arrow_result<ValueType,Reference,Pointer>::make(Reference)' 1> with 1> [ 1> ValueType=ATL::CComBSTR, 1> Reference=ATL::CComBSTR &, 1> Pointer=ATL::CComBSTR * 1> ] 1> c:\dev\vendor\boost\1.37.0\boost\iterator\iterator_facade.hpp(641) : see reference to class template instantiation 'boost::detail::operator_arrow_result<ValueType,Reference,Pointer>' being compiled 1> with 1> [ 1> ValueType=ATL::CComBSTR, 1> Reference=ATL::CComBSTR &, 1> Pointer=ATL::CComBSTR * 1> ] 1> c:\dev\vendor\boost\1.37.0\boost\iterator\iterator_adaptor.hpp(271) : see reference to class template instantiation 'boost::iterator_facade<Derived,Value,CategoryOrTraversal,Reference,Difference>' being compiled 1> with 1> [ 1> Derived=test::atl::CAdapt_iterator<std::_Vector_iterator<ATL::CAdapt<ATL::CComBSTR>,std::allocator<ATL::CAdapt<ATL::CComBSTR>>>>, 1> Value=ATL::CComBSTR, 1> CategoryOrTraversal=std::random_access_iterator_tag, 1> Reference=ATL::CComBSTR &, 1> Difference=__w64 int 1> ] 1> c:\dev\personal\boost\iterator_adaptor_bug\main.cpp(65) : see reference to class template instantiation 'boost::iterator_adaptor<Derived,Base,Value,Traversal,Reference>' being compiled 1> with 1> [ 1> Derived=test::atl::CAdapt_iterator<std::_Vector_iterator<ATL::CAdapt<ATL::CComBSTR>,std::allocator<ATL::CAdapt<ATL::CComBSTR>>>>, 1> Base=std::_Vector_iterator<ATL::CAdapt<ATL::CComBSTR>,std::allocator<ATL::CAdapt<ATL::CComBSTR>>>, 1> Value=ATL::CComBSTR, 1> Traversal=std::random_access_iterator_tag, 1> Reference=ATL::CComBSTR & 1> ] 1> c:\dev\personal\boost\iterator_adaptor_bug\main.cpp(103) : see reference to class template instantiation 'test::atl::CAdapt_iterator<Iterator>' being compiled 1> with 1> [ 1> Iterator=std::_Vector_iterator<ATL::CAdapt<ATL::CComBSTR>,std::allocator<ATL::CAdapt<ATL::CComBSTR>>> 1> ] Thanks for any insight, --Michael Fawcett

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Re: [Boost-users] Dijkstra shortest path
by Florian.PONROY＠fr.thalesgroup.com 23 Mar '09

23 Mar '09

Hi, The following algorithm should do the trick: // predecessors is the predecessor map // destinationNode is the node you want to reach // sourceNode is the source of the graph int currentNode = destinationNode; int predecessorNode = 0; std::cerr << boost::format("--- PATH: %d <- ") % destinationNode; do { predecessorNode = predecessors[currentNode]; if (predecessorNode == currentNode) { // Unreachable nextHop = 0; std::cerr << "XXX" << std::endl; break; } else if (predecessorNode == sourceNode) { // Next hop found nextHop = currentNode; std::cerr << sourceNode << std::endl; break; } else { // One hop on the path currentNode = predecessorNode; std::cerr << boost::format("%d <- ") % currentNode; } } while (true); Hope it helps, Florian -----Message d'origine----- De : boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org]De la part de dwaem Envoyé : lundi 23 mars 2009 16:23 À : boost-users(a)lists.boost.org Objet : Re: [Boost-users] Dijkstra shortest path Steven Watanabe-4 wrote: > > AMDG > > dwaem wrote: >> int weight[] = {1, 1, 2, 2, 3, 4, 3, 4, 5, 6, 7}; >> >> <snip> >> >> it shows >> distances and parents: >> distance(A) = 0, parent(A) = C >> distance(B) = 0, parent(B) = A >> distance(C) = 0, parent(C) = C >> distance(D) = 0, parent(D) = C >> distance(E) = 0, parent(E) = C >> >> >> which makes no sense. >> > > You're not using the weight array anywhere, > so you get the default weight of 0 for every edge. > > In Christ, > Steven Watanabe > > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users > > Yes this is my obviouse oversight. But now when I have founded shortest path from node A to node B. How to display full path from A to B, not only parent of the last node. -- View this message in context: http://www.nabble.com/Dijkstra-shortest-path-tp22626827p22662345.html Sent from the Boost - Users mailing list archive at Nabble.com. _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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Dijkstra shortest path
by dwaem 23 Mar '09

23 Mar '09

Hi I made a little change to example from manual which search shortest path http://www.boost.org/doc/libs/1_37_0/libs/graph/example/dijkstra-example.cpp http://www.boost.org/doc/libs/1_37_0/libs/graph/example/dijkstra-example.cpp by adding add_edge function but is seams to give incorect results #include <boost/config.hpp> #include <algorithm> #include <vector> #include <utility> #include <iostream> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/reverse_graph.hpp> #include <boost/graph/graph_utility.hpp> #include <boost/graph/dijkstra_shortest_paths.hpp> #include <boost/graph/graph_traits.hpp> #include <boost/graph/adjacency_list.hpp> using namespace boost; int main() { typedef adjacency_list < vecS, vecS, bidirectionalS, no_property, property < edge_weight_t, int > > graph; typedef graph_traits < graph >::vertex_descriptor vertex_descriptor; typedef graph_traits < graph >::edge_descriptor edge_descriptor; graph G(5); enum nodes { A, B, C, D, E }; add_edge(A, E, G); add_edge(B, E, G); add_edge(C, E, G); add_edge(A, B, G); add_edge(B, D, G); add_edge(B, A, G); add_edge(B, C, G); add_edge(C, A, G); add_edge(C, D, G); add_edge(D, A, G); add_edge(D, B, G); int weight[] = {1, 1, 2, 2, 3, 4, 3, 4, 5, 6, 7}; char name[] = "ABCDE"; std::cout << "\n"; vertex_descriptor s = vertex(C, G); property_map<graph, edge_weight_t>::type weightmap = get(edge_weight, G); std::vector<vertex_descriptor> p(num_vertices(G)); std::vector<int> d(num_vertices(G)); dijkstra_shortest_paths(G, s, predecessor_map(&p[0]).distance_map(&d[0])); std::cout << "distances and parents:" << std::endl; graph_traits < graph >::vertex_iterator vi, vend; for (tie(vi, vend) = vertices(G); vi != vend; ++vi){ std::cout << "distance(" << name[*vi] << ") = " << d[*vi] << ", "; std::cout << "parent(" << name[*vi] << ") = " << name[p[*vi]] << std::endl; } std::cout << std::endl; } it shows distances and parents: distance(A) = 0, parent(A) = C distance(B) = 0, parent(B) = A distance(C) = 0, parent(C) = C distance(D) = 0, parent(D) = C distance(E) = 0, parent(E) = C which makes no sense. Marcin Matuszak -- View this message in context: http://www.nabble.com/Dijkstra-shortest-path-tp22626827p22626827.html Sent from the Boost - Users mailing list archive at Nabble.com.

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[lambda]How can I call function of objects in std::list while using std::for_each?
by 钱晓明 23 Mar '09

23 Mar '09

Please help me! I want to call a virtual function of objects in std::list while using std::for_each: struct DiscardableItem { void Discard() { std::cout<<"Discard item!"<<std::endl; } }; std::list<DiscardableItem*> items; items.push_back(new DiscardableItem); items.push_back(new DiscardableItem); std::for_each( items.rbegin(), items.rend(), _1->*&DiscardableItem::Discard ); But DiscardableItem::Discard does not be called. How can I make it work? thanks! I think lambda can solve this problem easily.

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[utility] addressof issue with classes having templated conversion operators
by Gevorg Voskanyan 23 Mar '09

23 Mar '09

Hi folks, I've came across a problem with addressof() when the argument is of a class type with a template conversion operator. A minimal test case reproducing the issue is attached. Using boost 1.38, the example fails to compile under gcc 4.2.2, with the following error: ../../../../vendor/boost/boost_1_38_0/boost/utility/addressof.hpp: In function 'T* boost::addressof(T&) [with T = convertible]': addressof_conversion.cpp:17: instantiated from here boost/boost_1_38_0/boost/utility/addressof.hpp:42: error: ISO C++ says that these are ambiguous, even though the worst conversion for the first is better than the worst conversion for the second: ../../../../vendor/boost/boost_1_38_0/boost/utility/addressof.hpp:26: note: candidate 1: static T* boost::detail::addressof_impl<T>::f(T&, long int) [with T = convertible] ../../../../vendor/boost/boost_1_38_0/boost/utility/addressof.hpp:32: note: candidate 2: static T* boost::detail::addressof_impl<T>::f(T*, int) [with T = convertible] AFAICT gcc is right complaining here, according to 13.3.3 The same example compiles OK with boost 1.33.1, and the changeset that causes the difference seems to be this one: https://svn.boost.org/trac/boost/changeset/44705 Can this be considered a regression? How should this issue be addressed? Thanks, Gevorg

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Suggestion about using Signals2
by Daniele Barzotti 23 Mar '09

23 Mar '09

Hi, I need some help on using signals2 in my app, I hope to explain my problem well. I have a thread that reads from the RS232: void SerialPort::reading() { ... read... if (data_available) signal_OnData; } the signal_OnData is: typedef boost::signals2::signal<void ()> _signal_void; _signal_void signal_OnData; And I connect it to a method MyUserClass::OnDataReceived() Into this method (MyUserClass::OnDataReceived) I need to re-send some data to RS232, but the SerialPort::reading thread is locked because it's waiting the OnDataReceived ends.. In fact, when the methods OnDataReceived ends, I receive data again. How can I solve this problem? Thanks in advance! Daniele.

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Re: [Boost-users] [Graph] Computing reachable vertices on a graph
by Florian.PONROY＠fr.thalesgroup.com 23 Mar '09

23 Mar '09

Hi Andrew, Thank you very much for your reply. I eventually implemented Steven Watanabe's solution, which seems easier to me. Since I only need to know which nodes are actually reachable, I may get rid of distances for now. Thanks again, Florian -----Message d'origine----- De : boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org]De la part de Andrew Sutton Envoyé : vendredi 20 mars 2009 18:35 À : boost-users(a)lists.boost.org Objet : Re: [Boost-users] [Graph] Computing reachable vertices on a graph However, I encounter the following issue : in this example, vertices are numbered from 0 to 5. However, in my project, this is not the case, vertices could be numbered 5, 38, 42, 384... Using a vector in that case might not work as expected, a map<vertex, distance> would probably be better. I'm not quite familiar with BGL so far, maybe should I deal with a specific property map? Or using a visitor to record a vertex distance upon graph discovery? I'm a little bit lost, any help will be greatly appreciated! You probably shouldn't rely on vertex indices as the canonical id of the vertex. The method of identifying vertices (and edges) in an adjacency list varies with the vertex set and edge set type selectors (indices or identifeirs for vecS aren't the same as listS). There are a couple of different approaches. The easiest would be to simply maintain a mapping of id to vertex descriptor. For example: map<int, graph_traits<Graph>::vertex_descriptor> verts; verts[5] = add_vertex(g); verts[58] = add_vertex(g); // and so on. You can couple that bundled vertex properties to get a kind of bimap. struct vertex_props { int id; } typedef adj_list<vecS, vecS, directedS, vertex_props> Graph; template <typename Graph, typename Map> void add_vertex(Graph& g, Map& verts, int id) { vertex_descriptor v = add_vertex(g); verts[id] = v; g[v].id = id; } add_vertex(g, verts, 5); add_vertex(g, verts, 58); ... cout << g[*vertices(g).begin]->id << "\n"; Hope that helps, Andrew Sutton andrew.n.sutton(a)gmail.com <mailto:andrew.n.sutton@gmail.com>

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Re: [Boost-users] [Graph] Computing reachable vertices on a graph
by Florian.PONROY＠fr.thalesgroup.com 23 Mar '09

23 Mar '09

Hi Steven, I just tried your solution, which works perfectly well. The vector is actually sized to the number of reachable nodes. I just added a reachable.reserve(max_number_of_nodes) to avoid multiple reallocations. Thank you very much for your help, Florian -----Message d'origine----- De : boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org]De la part de Steven Watanabe Envoyé : vendredi 20 mars 2009 18:36 À : boost-users(a)lists.boost.org Objet : Re: [Boost-users] [Graph] Computing reachable vertices on a graph AMDG Florian.PONROY(a)fr.thalesgroup.com wrote: > I need to get the list of all reachable vertices from a given vertex in a graph. I'm currently using the BFS algorithm to achieve that, which seems to fit well to my need. > How does this work: #include <boost/graph/adjacency_list.hpp> #include <boost/graph/breadth_first_search.hpp> #include <boost/graph/visitors.hpp> #include <vector> #include <iterator> typedef boost::adjacency_list< boost::vecS, boost::vecS, boost::directedS > Graph; int main() { Graph G(1); boost::add_edge(0, 1, G); boost::add_edge(1, 2, G); boost::add_edge(2, 5, G); boost::add_edge(3, 2, G); boost::add_edge(4, 3, G); boost::add_edge(5, 3, G); typedef Graph::vertex_descriptor Vertex; std::vector<Vertex> reachable; // The source vertex Vertex s = *(boost::vertices(G).first); boost::breadth_first_search(G, s, boost::visitor( boost::make_bfs_visitor( boost::write_property( boost::identity_property_map(), std::back_inserter(reachable), boost::on_discover_vertex())))); } In Christ, Steven Watanabe _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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trouble with correct type definition of multi_index::nth_index
by Sandeep Gupta 23 Mar '09

23 Mar '09

Hi, In the following code I am trying to get an handle to the index of a multi_index container. The compiler says "invalid initialization of reference of type ‘boost::multi_index::detail:..". Not sure why this is so. Since I wasn't sure about the source of error I have pasted the full code ( sans declarations) is give below. Thanks sandeep ///-------------------------Full code --------------------- template<typename Col1_t, typename Col2_t, typename Col3_t, typename Col4_t> class TupleStore { typedef tuple<Col1_t, Col2_t, Col3_t, Col4_t> tuple_t; typedef multi_index_container < tuple_t, indexed_by < ordered_unique<tuple_member_extractor<tuple_t,0> > > > tuplestore_t; tuplestore_t m_tuplestore; public: template<int n> void lookup_key(Col1_t key) const { typedef typename tuplestore_t:: template nth_index<n>::type tuplestore_index_t; ///compiler error here tuplestore_index_t& indexx = m_tuplestore.get<n>(); } }; int main() { TupleStore<int,int,int,int> tstr; tstr.lookup_key<0>(5); }

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phoenix for_each and std::cout
by Sandeep Gupta 23 Mar '09

23 Mar '09

Hi, I am trying to use phoenix::for_each to print each element of iterator range. Would appreciate if any clarification as to why statements 1 and 2 are giving compile errors. Thanks sandeep //-------------code snippet int x; counting_iterator<int> first(0), last(10); iterator_range<counting_iterator<int> > ir(first, last); phoenix::for_each(ir, std::cout<<x<<' ')(); //stmt 1 ; compile error phoenix::for_each(ir, std::cout<<arg1<<' ')(); //stmt 2; compile error

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Struggling to compile encfs, linking with boost library
by Jean Jordaan 22 Mar '09

22 Mar '09

Hi there I want to use encfs on a box with a Debian distro that doesn't have recent encfs and boost packages available, so I'm compiling them from source. I installed boost like this:: $ ./configure --prefix=/home/zope/local It seems to complete fine. This incantation finds the libraries, but dies shortly thereafter:: zope@iwlearn:/home/zope/src/encfs-1.5$ CPPFLAGS=-I/home/zope/local/include/boost-1_38 ./configure --with-boost-libdir=/home/zope/local/lib --prefix=/home/zope/local [...] checking for boostlib >= 1.34... yes checking whether the Boost::System library is available... yes checking for exit in -lboost_system-gcc41-mt-1_38... yes configure: WARNING: BOOST_CPPFLAGS -I/usr/include checking whether the Boost::Serialization library is available... yes checking for exit in -lboost_serialization-gcc41-mt-1_38... yes checking whether the Boost::Filesystem library is available... yes checking for exit in -lboost_filesystem-gcc41-mt-1_38... no checking for exit in -lboost_filesystem-gcc41-mt-1_38... (cached) no checking for exit in -lboost_filesystem-gcc41-mt-1_38... (cached) no checking for exit in -lboost_filesystem-gcc41-mt... no checking for exit in -lboost_filesystem-gcc41-mt... (cached) no configure: error: Could not link against boost_filesystem-gcc41-mt ! I wonder why "checking for exit" works in -lboost_serialization-gcc41-mt-1_38 and not in -lboost_filesystem-gcc41-mt-1_38 .. What does that mean, "checking for exit"? (Googling ..) -- jean . .. .... //\\\oo///\\

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Boost and C++ "physical design"
by Yang Zhang 22 Mar '09

22 Mar '09

I have a couple questions about Boost and its implications for the "physical design" of C++ projects. I'm guessing there probably aren't that many non-member, non-template functions in the Boost library, but of the ones that exist, are these usually labeled `static`, since boost is mostly a header library? Is there any advice on taming (1) the generated code size and/or (2) the build times* which result from using a header-mostly library like Boost? A large C++ project consists of many translation units (.o files) which are generated from source files that include many of the same Boost headers over and over again. (2) can be ameliorated with a distributed build process, but the more general issue here is that of consumption of compute resources, be it time or machines. -- Yang Zhang http://www.mit.edu/~y_z/

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[numeric::converter] finding the smallest c such that (a/c) + (b/c) < inf
by er 22 Mar '09

22 Mar '09

Hi All, template<typename T> struct promote{}; template<> struct promote<float> : mpl::identity<double>{}; template<> struct promote<double> : mpl::identity<long double>{}; template<typename T> //T: float, double struct fit_a_plus_b_to_range{ static T divider(T a, T b){ static const T mx = math::tools::max_value<T>(); static const T mi = math::tools::min_value<T>(); if(a > (mx - b)){ typedef typename promote<T>::type prom_t; typedef numeric::converter<T,prom_t> up_t; typedef numeric::converter<prom_t,T> down_t; prom_t au = up_t::convert(a); prom_t bu = up_t::convert(b); prom_t mu = up_t::convert(mx); prom_t cu = ((au/mu)+(bu/mu)); T delta = ...; T c = down_t::convert(cu) + delta; BOOST_ASSERT(!math::isinf((a/c)+(b/c))); return c; }else{ return (T)(1); } } }; With delta = 0.0 the assertion fails, with delta = 1.0 it works (for a few examples). What's the smallest delta value? Is there a better way to do this overall? If this is off topic, let me know...

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Serialization of a std::vector< boost::shared_ptr< A > > throws unregistered_class exception
by Benoit Gagnon 21 Mar '09

21 Mar '09

Given the following classes: class Building { ... }; class House : public Building { ... }; class Hospital : public Building { ... }; With appropriate serialization method templates such as: class House: public Building { friend class boost::serialization::access; template<class Archive> void serialize(Archive& ar, const unsigned int version ) { ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP( Building ); ar & BOOST_SERIALIZATION_NVP( mNumBedrooms ); ar & BOOST_SERIALIZATION_NVP( mNumBathrooms ); } ... I have the following registrations in main.cpp where the archiving/ restoring is performed: BOOST_SERIALIZATION_SHARED_PTR( Building ) BOOST_SERIALIZATION_SHARED_PTR( House ) BOOST_SERIALIZATION_SHARED_PTR( Hospital ) In main.ccp, I would like to serialize a std::vector< boost::shared_ptr< Building > > object. Like this: std::vector< boost::shared_ptr< Building > > buildings; ... std::ofstream ofs( "archive.txt" ); boost::archive::text_oarchive oa( ofs ); oa & BOOST_SERIALIZATION_NVP( buildings ); This compiles correctly but fails at runtime with a "unregistered_class" exception. The individual classes (Building, House, Hospital) can be serialized and restored fine individually. That is true for objects, pointers and shared_ptr. A vector of plain pointers to any of those types also works fine. But a vector of shared_ptr to any of those types fails at runtime.. What kind of registration must be done to achieve this?

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[math] log_max_value<long double>
by er 21 Mar '09

21 Mar '09

Hi All, Was this discussed before? <cmath> using namespace math::tools; typedef double RealType; log_max_value<RealType>() 709 log(max_value<RealType>()) 709.783 !math::isinf(exp(log_max_value<RealType>())) //true typedef long double RealType; log_max_value<RealType>() 11356 log(max_value<RealType>()) inf !math::isinf(exp(log_max_value<RealType>())) //false i.e. exp in cmath seems to "assume" RealType = double. i686-apple-darwin9-gcc-4.0.1

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shared_ptr as reference argument
by anony 20 Mar '09

20 Mar '09

Is there some utility in passing shared_ptr's as references as here: void bla(boost::shared_ptr<T>& bla_ptr); This avoids creating of a new object and copying overhead, but is it safe? When would you recommend it and when not?

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[Tuple] Help getting started with Tuple-based meta-programming
by Dominique Devienne 20 Mar '09

20 Mar '09

Hi All. I outline below code I keep writing which I'd like to replace with a sql_get_rows template function which would use the meta-type information bundled in the tuple declaration to automatically make as many calls to the get<T> function based on the tuple length, and "pack" the result of these calls into a tuple instance added to a container (vector in this case, but if it could be generalized to any container, all the better, although I'd be happy just with vector). I have experience with basic template stuff, and a little less basic stuff like CRTP, enable_if, and the like, but meta-programming is still new to me, which is why I'm seeking advice from experts to find out whether the below is : 1) possible, 2) would perform ok, and 3) where I should start looking to see examples doing this particular "tuple-enrolling" or perhaps even pseudo code outlining how one would go about implementing this, provided answers to (1) and (2) are positive of course. I suspect mpl and phoenix would need to be used, from the reading I've done, but the path to follow is quite unclear to me still. Any help in this matter would be appreciated. Thanks, --DD // Context: retrieving all the rows (result set) from a given SQL query. // pseudo code of boilerplate code I keep repeating right now struct { int id; std::string name; } Row; void doit() { ResultSet rset = sql_exec("select id, name from t"); std::vector<Row> rows; while (rset.hasMoreRows()) { Row row; row.id = rset.get<int>(0); row.name = rset.get<const char*>(1); rows.push_back(row); } // process rows } // Code I'd like to write instead void doit() { typedef boost::tuple<int, std::string> Row; std::vector<Row> rows; sql_get_rows("select id, name from t", rows); // optional arg to get only first N elements // process rows } PS: returning the vector would be better, but because of the copy involved I guess I must pass it as a non-const ref instead, to fill it up. Will the new move semantic from the upcoming standard allow a function to return the vector without the copy? Just curious.

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[lambda] problem with g++
by Michał Nowotka 20 Mar '09

20 Mar '09

following code does not compile with g++ while under vs2008 it works fine: //window.h ///(...) class Window { //(...) protected: //(...) double evaluate(const vector<double>& win_probabls) const; //(...) } //(...) //window.cpp #include "window.h" #include <boost/lambda/lambda.hpp> #include <boost/lambda/bind.hpp> #include <algorithm> #include <numeric> #include <cmath> //(...) double Window::evaluate(const vector<double>& win_probabls) const { return accumulate (win_probabls.begin(), win_probabls.end(), 0.0, lambda::_1 + lambda::bind(log, lambda::_2) ); } //(...) g++ returns following error: src/window.cpp:92: error: no matching function for call to 'bind(<unresolved overloaded function type>, const boost::lambda::lambda_functor<boost::lambda::placeholder<2> >&)' make: *** [build/window.o] Error 1 and I don't know what shuld I change to make it work for me... -- Regards Michał Nowotka

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[Tuple] online doc for 1.38 links to empty page
by Dominique Devienne 20 Mar '09

20 Mar '09

FYI: The link http://www.boost.org/doc/libs/1_38_0/libs/tuple/doc/tuple_advanced_interfac… referenced from http://www.boost.org/doc/libs/1_38_0/libs/tuple/doc/tuple_users_guide.html yields an empty page (modulo the page banner). The link is correct OTOH in my local install. Thanks, --DD

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Re: [Boost-users] No packets received with boost::asio::ip::udp::socket set to multicast group
by danielej 20 Mar '09

20 Mar '09

I think you need to bind to the multicast group, not the interface, in linux(as I discovered this week, it is the opposite in windows.) I am still trying to figure out how to specify the interface in linux using join_group so if you find out how please add that to the post. hope this helps, Dan -- View this message in context: http://www.nabble.com/No-packets-received-with-boost%3A%3Aasio%3A%3Aip%3A%3… Sent from the Boost - Users mailing list archive at Nabble.com.

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[Graph] Computing reachable vertices on a graph
by Florian.PONROY＠fr.thalesgroup.com 20 Mar '09

20 Mar '09

Hi all, I need to get the list of all reachable vertices from a given vertex in a graph. I'm currently using the BFS algorithm to achieve that, which seems to fit well to my need. To understand its behavior, I simplified the http://www.boost.org/doc/libs/1_38_0/libs/graph/example/bfs.cpp example source code to this : typedef boost::adjacency_list< boost::vecS, boost::vecS, boost::directedS > Graph; Graph G(1); boost::add_edge(0, 1, G); boost::add_edge(1, 2, G); boost::add_edge(2, 5, G); boost::add_edge(3, 2, G); boost::add_edge(4, 3, G); boost::add_edge(5, 3, G); typedef Graph::vertex_descriptor Vertex; std::vector<int> distances; distances.reserve(6); std::fill_n(&distances[0], 6, 0); // The source vertex Vertex s = *(boost::vertices(G).first); boost::breadth_first_search(G, s, boost::visitor(boost::make_bfs_visitor(boost::record_distances(&distances[0], boost::on_tree_edge())))); boost::print_graph(G); for (int i = 0; i < 6; i++) { std::cout << "Node " << i << " : "; if (distances[i] != 0) std::cout << "reachable, distance " << distances[i] << std::endl; else std::cout << "not reachable" << std::endl; } However, I encounter the following issue : in this example, vertices are numbered from 0 to 5. However, in my project, this is not the case, vertices could be numbered 5, 38, 42, 384... Using a vector in that case might not work as expected, a map<vertex, distance> would probably be better. I'm not quite familiar with BGL so far, maybe should I deal with a specific property map? Or using a visitor to record a vertex distance upon graph discovery? I'm a little bit lost, any help will be greatly appreciated! Thank you very much, -- Florian PONROY Thales Land & Joint France Tel. : +33(0)1 41 304 363 Fax : +33(0)1 41 303 560 Email : florian.ponroy(a)fr.thalesgroup.com

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Bug in boost.asio ssl::stream write_some read_some methods?
by Michael Peltonen 20 Mar '09

20 Mar '09

Hi, When I compile my program that uses synchronous ssl::stream methods read_some and write_some, the compiler complains about ambigious binds. I believe this is a bug in the boost.asio library. My code compiled and run fine on boost_1_36_0 in windows environment, but not with boost_1_37_0 or boost_1_38_0 on solaris SPARC 10 environment? Boost compiles fine without any errors on solaris, so I believe this is a new boost.asio bug that has been introduced in the newest two releases. I tried to confirm this by building boost_1_36_0 on my solaris machine, but could not get it to compile without errors. The error message: /usr/local/include/boost/asio/ssl/detail/openssl_stream_service.hpp: In member function `size_t boost::asio::ssl::detail::openssl_stream_service::read_some(boost::asio::ssl::detail::openssl_stream_service::impl_struct*&, Stream&, const Mutable_Buffers&, boost::system::error_code&) [with Stream = boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp> >, Mutable_Buffers = boost::asio::mutable_buffers_1]': /usr/local/include/boost/asio/ssl/stream_service.hpp:149: instantiated from `size_t boost::asio::ssl::stream_service::read_some(boost::asio::ssl::detail::openssl_stream_service::impl_struct*&, Stream&, const MutableBufferSequence&, boost::system::error_code&) [with Stream = boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp> >, MutableBufferSequence = boost::asio::mutable_buffers_1]' /usr/local/include/boost/asio/ssl/stream.hpp:397: instantiated from `size_t boost::asio::ssl::stream<Stream, Service>::read_some(const MutableBufferSequence&, boost::system::error_code&) [with MutableBufferSequence = boost::asio::mutable_buffers_1, Stream = boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp> >, Service = boost::asio::ssl::stream_service]' program.cpp:691: instantiated from here /usr/local/include/boost/asio/ssl/detail/openssl_stream_service.hpp:416: error: call of overloaded `bind(int (*)(SSL*, void*, int), boost::arg<1>, void*, int)' is ambiguous /usr/local/include/boost/bind.hpp:1298: note: candidates are: boost::_bi::bind_t<R, F, typename boost::_bi::list_av_3<a1, A2, A3>::type> boost::bind(F, A1, A2, A3) [with R = int, F = int (*)(SSL*, void*, int), A1 = boost::arg<1>, A2 = void*, A3 = int] /usr/local/include/boost/bind/bind_cc.hpp:47: note: boost::_bi::bind_t<R, R (*)(B1, B2, B3), typename boost::_bi::list_av_3<a1, A2, A3>::type> boost::bind(R (*)(B1, B2, B3), A1, A2, A3) [with R = int, B1 = SSL*, B2 = void*, B3 = int, A1 = boost::arg<1>, A2 = void*, A3 = int] /usr/local/include/boost/asio/ssl/detail/openssl_stream_service.hpp: In member function `size_t boost::asio::ssl::detail::openssl_stream_service::write_some(boost::asio::ssl::detail::openssl_stream_service::impl_struct*&, Stream&, const Const_Buffers&, boost::system::error_code&) [with Stream = boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp> >, Const_Buffers = boost::asio::const_buffers_1]': /usr/local/include/boost/asio/ssl/stream_service.hpp:132: instantiated from `size_t boost::asio::ssl::stream_service::write_some(boost::asio::ssl::detail::openssl_stream_service::impl_struct*&, Stream&, const ConstBufferSequence&, boost::system::error_code&) [with Stream = boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp> >, ConstBufferSequence = boost::asio::const_buffers_1]' /usr/local/include/boost/asio/ssl/stream.hpp:320: instantiated from `size_t boost::asio::ssl::stream<Stream, Service>::write_some(const ConstBufferSequence&, boost::system::error_code&) [with ConstBufferSequence = boost::asio::const_buffers_1, Stream = boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp> >, Service = boost::asio::ssl::stream_service]' program.cpp:704: instantiated from here /usr/local/include/boost/asio/ssl/detail/openssl_stream_service.hpp:342: error: call of overloaded `bind(int (*)(SSL*, const void*, int), boost::arg<1>, const void*, int)' is ambiguous /usr/local/include/boost/bind.hpp:1298: note: candidates are: boost::_bi::bind_t<R, F, typename boost::_bi::list_av_3<a1, A2, A3>::type> boost::bind(F, A1, A2, A3) [with R = int, F = int (*)(SSL*, const void*, int), A1 = boost::arg<1>, A2 = const void*, A3 = int] /usr/local/include/boost/bind/bind_cc.hpp:47: note: boost::_bi::bind_t<R, R (*)(B1, B2, B3), typename boost::_bi::list_av_3<a1, A2, A3>::type> boost::bind(R (*)(B1, B2, B3), A1, A2, A3) [with R = int, B1 = SSL*, B2 = const void*, B3 = int, A1 = boost::arg<1>, A2 = const void*, A3 = int] make: *** [program.o] Error 1 The code: boost::asio::io_service io_service; boost::asio::ip::tcp::acceptor acceptor(io_service, boost::asio::ip::tcp::endpoint(boost::asio::ip::tcp::v4(), 7722)); boost::asio::ssl::context context(io_service, boost::asio::ssl::context::sslv23); context.set_options( boost::asio::ssl::context::default_workarounds | boost::asio::ssl::context::no_sslv2 | boost::asio::ssl::context::single_dh_use); context.set_verify_mode( boost::asio::ssl::context::verify_peer | boost::asio::ssl::context::verify_fail_if_no_peer_cert); context.use_certificate_chain_file("server-public.pem"); context.use_private_key_file("server-private.pem", boost::asio::ssl::context::pem); context.use_tmp_dh_file("dh4096.pem"); context.load_verify_file("client-public.pem"); while(!exit) { for (;;) { std::string message; boost::array<char, 128> buf; boost::system::error_code error; boost::asio::ssl::stream<boost::asio::ip::tcp::socket> socket(io_service, context); acceptor.accept(socket.lowest_layer()); socket.handshake(boost::asio::ssl::stream_base::server); size_t len = socket.read_some(boost::asio::buffer(buf), error); if (error == boost::asio::error::eof) break; // Connection closed cleanly by peer. else if (error) throw boost::system::system_error(error); // Some other error. message.assign(buf.data(), len); if(message.compare("statistics") == 0) message = statistics_reply(); else message = error_reply(); boost::system::error_code ignored_error; socket.write_some(boost::asio::buffer(message), ignored_error); } } Regards, -Michael

1 0

[mpl] for_each and set_c: misunderstanding or bug?
by Nevin ":-]" Liber 19 Mar '09

19 Mar '09

A friend of mine is having problems using setc with for_each. Given the following code: struct p { template<typename T> void operator()(T) const { std::cout << typeid(T).name() << std::endl; } }; typedef mpl::vector_c<int, 1, 2> vc; typedef mpl::set< mpl::integral_c<int, 1>, mpl::integral_c<int, 2> > si; typedef mpl::set_c<int, 1, 2> sc; int main() { mpl::for_each<vc>(p()); mpl::for_each<si>(p()); mpl::for_each<sc>(p()); // line does not compile } Under gcc 4.0.1 and Boost 1.38.0, we get the following error messages for the line in question: boost/mpl/next_prior.hpp:30: error: no type named 'base' in 'struct boost::mpl::set0_c<int>' boost/mpl/eval_if.hpp:38: error: no type named 'type' in 'struct boost::mpl::next<boost::mpl::s_iter<sc, boost::mpl::set0_c<int> > >' boost/mpl/for_each.hpp:78: error: 'value' is not a member of '<declaration error>' boost/mpl/for_each.hpp:78: error: 'execute' is not a member of '<declaration error>' Is this a misunderstanding on how to use for_each and set_c on our part? Regards, -- Nevin ":-)" Liber <mailto:nevin@eviloverlord.com> (847) 691-1404

2 1

[version 1.38.0] Problems with dynamic linking to boost libraries
by Juan Antonio Farré Basurte 19 Mar '09

19 Mar '09

Hello, I'm using boost libraries in my research work and I need to link to graph and program options libraries. I've been working with version 1.37.0 without any problem. Now I updated to 1.38.0. I built the libraries in the same way and the same directories as 1.37.0 (on /usr/local). The compilation and dynamic linkage phase work, but when I run the program it complains with "file not found" on the shared library files. I've tried it in my home Fedora 10 installation and the Debian installation at my workplace and I have the same problem. For the moment, the only workaround I've found is explicitly linking the static versions of both libraries, while still dynamically linking to other libraries (like expat). Is there any problem in the installation phase of "./configure ; make install"? What can I do? Thanks in advance.

5 15

Boost Serialization - Base Classes (very confused)
by Adrien Guillon 19 Mar '09

19 Mar '09

Hi all, I don't understand why the following code does not work. I get an unregistered class exception. AJ #include <boost/serialization/serialization.hpp> #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/serialization/export.hpp> #include <string> #include <sstream> #include <iostream> namespace pbb { // BEGIN NAMESPACE pbb namespace internal { // BEGIN NAMESPACE internal /** * The base class for all requests to be made of a server. */ class server_request { friend class boost::serialization::access; public: virtual ~server_request(); virtual std::string description() = 0; private: template <typename Archive> void serialize(Archive& ar, const unsigned int version) { } }; class hello_request : public server_request { friend class boost::serialization::access; public: virtual ~hello_request(); virtual std::string description(); private: template <typename Archive> void serialize(Archive& ar, const unsigned int version) { ar & boost::serialization::base_object<server_request>(*this); } }; } // END NAMESPACE internal } // END NAMESPACE pbb namespace pbb { // BEGIN NAMESPACE pbb namespace internal { // BEGIN NAMESPACE internal server_request::~server_request() { } hello_request::~hello_request() { } std::string hello_request::description() { return "HELLO REQUEST"; } } // END NAMESPACE internal } // END NAMESPACE pbb BOOST_CLASS_EXPORT(pbb::internal::server_request); BOOST_CLASS_EXPORT(pbb::internal::hello_request); void msave(const pbb::internal::server_request& request, boost::archive::text_oarchive& o) { o << request; } pbb::internal::server_request* mload(boost::archive::text_iarchive& in) { pbb::internal::server_request* r; in >> r; return r; } int main() { // Create a string stream for I/O std::stringstream stream; pbb::internal::server_request* request = new pbb::internal::hello_request(); // Write a server request { boost::archive::text_oarchive out_archive(stream); msave(*request, out_archive); } // Read a server request pbb::internal::server_request* incoming_request; { boost::archive::text_iarchive in_archive(stream); incoming_request = mload(in_archive); } std::cout << incoming_request->description() << std::endl; }

2 1