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Bind and shared_ptr
by Robin 03 Jun '04

03 Jun '04

Hi, The current bind defines the placeholder _1, _2 etc. I was wondering if there is another placeholder that will deference the placeholder if the container is holding pointers instead of copies? Usually I store shared_ptrs in containers instead of direct copies as they are polymorphic class C; // this is our object we are storing typedef boost::shared_ptr<C> CSP; std::vector<CSP> C_List; Now we have a function that operates on C void Operate(C &c); C_List clist; // the list of shared_ptrs to C // this won't compile std::for_each (clist.begin (), clist.end (), boost::bind (Operator,_1)); I have to make an auxillary function to compile void Wrap_Operate (CSP &c) { Operate(*c); } std::for_each (clist.begin (), clist.end (), boost::bind (Wrap_Operate, _1)); Is there to avoid making the additional function and have a placeholder that will dereference directly (eg *_1, *_2)? Can I have the cake and eat it? Robin

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(no subject)
by Mike Feldmeier 02 Jun '04

02 Jun '04

Hi everyone, Could someone please point me in the right direction with this one? : class data { int x; }; class worker { void run(&data d); }; void run_worker(worker& w, data& d) { boost::thread(boost::bind(&worker::run, &my_worker, _1)(boost:ref(my_data))); } void main() { worker my_worker; data my_data; run_worker(my_worker, my_data); } Compiling this yields.. test.cpp(24) : error C2440: 'type cast' : cannot convert from 'boost::_bi::bind_t<R,F,L>::result_type' to 'boost::thread' with [ R=void, F=boost::_mfi::mf1<void,worker,data &>, L=boost::_bi::list2<boost::_bi::list_av_2<worker *,boost::arg<1>>::B1,boost::_bi::list_av_2<worker *,boost::arg<1>>::B2> ] Expressions of type void cannot be converted to other types Can I not bind to functions with a void return type? Changing it to int, produces a similar message. Any help appreciated! Thanks, Mike _________________________________________________________________ FREE pop-up blocking with the new MSN Toolbar get it now! http://toolbar.msn.click-url.com/go/onm00200415ave/direct/01/

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bjam failed to build (mingw)
by krejci.lukas＠volny.cz 02 Jun '04

02 Jun '04

Hi, I have updated from CVS today, set the dev-cpp bin directory into PATH and run: build.bat mingw. This build has failed, attachment '1.txt' contains stdout&stderr outputs. Then I set two additional environment variables: set MINGW_ROOT_DIRECTORY=C:\Dev-Cpp set BOOST_JAM_TOOLSET_ROOT=C:\Dev-Cpp\ and again run: build.bat mingw. This build failed too, attachment '2.txt' contains stdout&stderr outputs. Am I something missing? Have a nice day, L.

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BGL: "degree" with listS
by Bayle Shanks 02 Jun '04

02 Jun '04

I have another question. The following code won't compile. But if you change the first "listS" to "vecS", then it does. I can't find anything in the docs which forbids the use of "degree" with adjacency_list <listS, listS, ... ------------- #include <boost/config.hpp> #include <list> #include <boost/graph/adjacency_list.hpp> using namespace boost; using namespace std; typedef property<vertex_color_t, default_color_type, property<vertex_distance_t,std::size_t, property<vertex_degree_t,std::size_t, property<vertex_in_degree_t, std::size_t, property<vertex_out_degree_t,std::size_t> > > > > VertexProperty; typedef adjacency_list<listS, listS, bidirectionalS, VertexProperty> Graph; typedef boost::graph_traits<Graph>::vertex_descriptor vertexType; int main(int, char*[]) { Graph g; vertexType v0; v0 = add_vertex(g); out_degree(v0, g); } ----------- the compile error is: ----------- /usr/include/boost/iterator/iterator_traits.hpp: In function `void std::distance(_InputIterator, _InputIterator, _Distance&) [with _InputIterator = std::_List_iterator<boost::detail::sei_<size_t, std::_List_iterator<boost::list_edge<size_t, boost::no_property>, boost::list_edge<size_t, boost::no_property>&, boost::list_edge<size_t, boost::no_property>*>, boost::no_property>, const boost::detail::sei_<size_t, std::_List_iterator<boost::list_edge<size_t, boost::no_property>, boost::list_edge<size_t, boost::no_property>&, boost::list_edge<size_t, boost::no_property>*>, boost::no_property>&, const boost::detail::sei_<size_t, std::_List_iterator<boost::list_edge<size_t, boost::no_property>, boost::list_edge<size_t, boost::no_property>&, boost::list_edge<size_t, boost::no_property>*>, boost::no_property>*>, _Distance = size_t]': /usr/include/g++-v3/bits/stl_list.h:307: instantiated from `size_t std::list<_Tp, _Alloc>::size() const [with _Tp = boost::detail::sei_<size_t, std::_List_iterator<boost::list_edge<size_t, boost::no_property>, boost::list_edge<size_t, boost::no_property>&, boost::list_edge<size_t, boost::no_property>*>, boost::no_property>, _Alloc = std::allocator<boost::detail::sei_<size_t, std::_List_iterator<boost::list_edge<size_t, boost::no_property>, boost::list_edge<size_t, boost::no_property>&, boost::list_edge<size_t, boost::no_property>*>, boost::no_property> >]' /usr/include/boost/graph/detail/adjacency_list.hpp:1409: instantiated from `typename Config::degree_size_type boost::out_degree(typename Config::vertex_descriptor, const boost::adj_list_helper<Config, Base>&) [with Config = boost::detail::adj_list_gen<boost::adjacency_list<boost::listS, boost::vecS, boost::bidirectionalS, VertexProperty, boost::no_property, boost::no_property, boost::listS>, boost::vecS, boost::listS, boost::bidirectionalS, VertexProperty, boost::no_property, boost::no_property, boost::listS>::config, Base = boost::bidirectional_graph_helper_with_property<boost::detail::adj_list_gen<boost::adjacency_list<boost::listS, boost::vecS, boost::bidirectionalS, VertexProperty, boost::no_property, boost::no_property, boost::listS>, boost::vecS, boost::listS, boost::bidirectionalS, VertexProperty, boost::no_property, boost::no_property, boost::listS>::config>]' graph2.cpp:26: instantiated from here /usr/include/boost/iterator/iterator_traits.hpp:54: `template<Iterator> struct boost::iterator_category' is not a function, /usr/include/g++-v3/bits/stl_iterator_base_types.h:196: conflict with `template<_Iter> typename std::iterator_traits::iterator_category std::iterator_category(const _Iter&)' /usr/include/g++-v3/bits/stl_iterator_base_funcs.h:102: in call to `iterator_category' ----------- thanks, bayle

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BGL: multigraphs with remove_edge_if
by Bayle Shanks 01 Jun '04

01 Jun '04

Hi, I have a question about the BGL. I'm trying to get remove_edge_if to work with a multigraph. The documentation doesn't seem to prohibit this: http://www.boost.org/libs/graph/doc/MutableGraph.html http://www.boost.org/libs/graph/doc/adjacency_list.html However, the following sample code crashes. It is intended to add two vertices v0 and v1, and to add two edges from v0 to v1, and then to remove all of the edges by passing an always-true predicate to remove_edge_if. ------------------- #include <boost/config.hpp> #include <iostream> // for std::cout #include <utility> // for std::pair #include <boost/utility.hpp> // for boost::tie #include <boost/graph/graph_traits.hpp> // for boost::graph_traits #include <boost/graph/adjacency_list.hpp> #include <boost/graph/graphviz.hpp> using namespace std; using namespace boost; typedef adjacency_list<vecS, vecS, bidirectionalS > UnderlyingGraphType; typedef boost::graph_traits<UnderlyingGraphType>::vertex_descriptor vertexType; typedef boost::graph_traits<UnderlyingGraphType>::edge_descriptor edgeType; class truePredicate { public: truePredicate() {} bool operator()(edgeType e){ cout << "edgePred got " << e <<endl; cout << "about to return true!!!" << endl; return true; } }; int main(int,char*[]) { UnderlyingGraphType G = UnderlyingGraphType(); vertexType v0, v1; edgeType e01_1, e01_2; bool inserted; v0 = boost::add_vertex(G); v1 = boost::add_vertex(G); cout << "v0: " << v0 << endl; cout << "v1: " << v1 << endl; boost::tie(e01_1, inserted) = boost::add_edge(v0,v1,G); cout << "e1: " << e01_1 << endl; cout << "ins1: " << inserted << endl; boost::tie(e01_2, inserted) = boost::add_edge(v0,v1,G); cout << "e2: " << e01_1 << endl; cout << "ins2: " << inserted << endl; boost::write_graphviz(cout,G); boost::remove_edge_if(truePredicate(), G); boost::write_graphviz(cout,G); } ------------------- I'm using Boost 1_31_0 on Debian GNU/Linux with g++-3.0. The result of running the above code on my system is: ------------------- v0: 0 v1: 1 e1: (0,1) ins1: 1 e2: (0,1) ins2: 1 digraph G { 0; 1; 0->1 ; 0->1 ; } edgePred got (0,1) about to return true!!! edgePred got (0,1) about to return true!!! edgePred got (0,1) about to return true!!! edgePred got (4294967295,1919379812) about to return true!!! Segmentation fault ------------------- thanks for your help, bayle p.s. btw, i'm in the process of wrapping BGL for Python using Boost::Python, in case anyone is interested.

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Graph Serialization
by Daniel Z 01 Jun '04

01 Jun '04

Hello, i'm trying to use the serialization library. I manage to serialize simple class, but now i would like to serialize a boost graph, but i can't find how to do it. Anyone can tell me how to begin? Thx. Plus simple, plus fiable, plus rapide : découvrez le nouveau Caramail - http://www.caramail.lycos.fr

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boost::variant: need help with 'get'
by Caleb Epstein 01 Jun '04

01 Jun '04

I'm trying to use the "get" template with boost::variant but can't figure out how to get my compiler to recognize it. Here's a simple test program: --- #include <iostream> #include <cmath> #include <string> #include <boost/variant.hpp> using namespace boost; using namespace std; typedef variant<int, double, string> elem_t; int main () { elem_t pi = M_PI; double d = get (pi); cout << "pi =~ " << d << endl; return 0; } --- But my compiler (gcc 3.3.2) tells me: g++ -I/home/tools/boost-1.31.0 test.cpp -o test test.cpp: In function `int main()': test.cpp:15: error: no matching function for call to `get(elem_t&)' I'm using Boost 1.31.0. Thanks for any help, -- Caleb Epstein | bklyn . org | The Golden Rule of Arts and Sciences: cae at | Brooklyn Dust | He who has the gold makes the rules. bklyn dot org | Bunny Mfg. |

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Boost::tokenizer and reverse iterators
by Jeff Holle 31 May '04

31 May '04

I'm using boost v1_31_0 and gcc v3.3.2 In experimenting with boost::tokenizer to meet a requirement that I have, I've tried hooking it to a reverse iterator. This act produced a run-time error. This is the code: const string test = "One:Two:Three:Four"; typedef char_separator<char> Sep; typedef tokenizer<Sep,string::const_reverse_iterator> Tok; Sep sep(":"); Tok t(test,sep); for (Tok::iterator iter=t.end();iter!=t.begin();++iter) cout << *iter << endl; Executing this produces continous output of "garbage". Switching the ".end()" and ".begin()" references in the for loop doesn't fix this problem. Switching from "const_reverse_iterator" to "const_iterator" produces the following output: One Two Three Four Is there a way to use a reverse iterator with boost:tokenizer?

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BGL: boost::read_graphviz()
by Andreas Scherer 31 May '04

31 May '04

Dear Group, During some initial experiments with the BGL-GraphViz interface, I observed a significant asymmetry between a given DOT graph input with boost::read_graphviz() and output with boost::write_graphviz() (without changing any attributes). Given the input DOT file (which is, of course, much longer with the full set of information) <metro.dot> graph metro { node[ fontname = "luxirr", style = filled, fillcolor = white ]; "Arts et Métiers"; subgraph ligne_1 { node[ fillcolor = "orange" ]; "La Défense/Grande Arch" -- "Esplanade de la Défense"; } } </metro.dot> The elementary BGL program <metro.cxx> #include <boost/graph/graphviz.hpp> int main( void ) { boost::GraphvizGraph g_dot; boost::read_graphviz( "metro.dot", g_dot ); boost::write_graphviz( "metro_boost.dot", g_dot ); } </metro.cxx> transforms this into the output DOT file <metro_boost.dot> graph ligne_1 { node [fillcolor="orange", fontname="luxirr", style="filled"]; subgraph ligne_1 { node [fillcolor="orange", fontname="luxirr", style="filled"]; 1[label="La Défense/Grande Arch"]; 2[label="Esplanade de la Défense"]; 1 -- 2; } 0[label="Arts et Métiers"]; } </metro_boost.dot> It seems that somewhere on the way, the graph and node (and edge) attributes get clobbered. Note that even the graph name "metro" gets replaced by the name of the (last) subgraph "ligne_1", and /all/ node attributes get mixed up. This seems to be somewhat similar to the recent edge-related problem posted by Hideaki Hiraki. I have not (yet) tried to mess with the graphviz parser code, so I am asking here for help. Thanks. Greetings, Andreas

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bjam hanging on MacOS X
by Nick Bastin 31 May '04

31 May '04

I downloaded Boost 1.31.0 and built bjam with the build.sh script. Now, when I try to build boost with bjam -sTOOLS=darwin install, it just hangs, with no output to the console at all. Is there a way to set it into a verbose mode to see what's going on, or does anybody have any idea what's wrong? This is MacOS X 10.3.3 (7G33) on a 12" powerbook G4 (1.33Ghz) with the latest developer tools (7K249). -- Nick

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