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

[Test] New documentation
by Hrvoje Prgeša 03 Aug '08

03 Aug '08

There used to be a better version of the documentation at http://www.patmedia.net/~rogeeff/html/index.html. However it's down at the moment and the official/current documentation is very lacking (and broken). Can the new documentation be found elsewhere? Hrvoje Prgeša

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[boost-users][Date Time] time_period containing specific day?
by Igor R 03 Aug '08

03 Aug '08

Hi, What's the best way to check whether a time_period contains some day of month (eg. 15th)? Thanks, Igor'.

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How to build a python extension using Visual C++ IDE instead of bjam?
by happybrowndog 03 Aug '08

03 Aug '08

Is there a way to build a boost python extension using Visual C++ IDE instead of bjam? Has anyone done it, and how is it done?

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[date_time and others] Boost's cstdint.hpp types in Boost libraries
by Ruediger Berlich 03 Aug '08

03 Aug '08

Hi there, I use the date_time library quite a bit, due to its power and ease of use (quote me on that ;-) . One of the things that make working with it a bit awkward (and I presume the same is true for some other Boost libraries) is that it doesn't use Boost integer types througout the entire library. E.g., the boost::posix_time::hours class expects a "long" , which on most (but probably not all) systems, will be the same as a boost::int32_t (and shouldn't it be an unsigned type ?). This means that, if I really want to adhere to each library's specifications, I have to support three integer type systems in an application: std::size_t for containers, boost::(u)intXX_t and the "traditional" (unsigned) short/int/long types. Instead I'm now just giving the hour/minute/... classes an int32_t . Having a common set of integer types throughout Boost would be high on my wishlist. Kind Regards / Mit freundlichen Gruessen, Ruediger Berlich

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[DateTime] 1.35.0: Patch to fix warning
by Peter Klotz 03 Aug '08

03 Aug '08

The attached patch fixes an unused parameter warning in boost/date_time/time.hpp. Best regards, Peter.

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Thread safe stack template or class ?
by Ramesh 03 Aug '08

03 Aug '08

Hello, Does boost provide a thread safe stack class implementation? Thanks /Ramesh

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BGL newbie kamada_kawai_spring_layout never returns
by Eric B 03 Aug '08

03 Aug '08

Hi I'm trying to use BGL to build a layout for a graph. I have my own graph representation which is used to feed a boost graph which I intend to use to compute vertices positions. The positions will then be used to update my own graph representation. It works for some graph but for some others kamada_kawai_spring_layout never returns. So I think the code is ok But I Might have missed something when using kamada_kawai_spring_layout. Is it limited to some specific graph topologies ?!!! Some hints or help would be greatly appreciated. Thank you. Here after the relevant part of the code and the execution logs The log produced: NB DE VERTICES 10 NB DE EDGES 14 UNDIRECTEED NB DE VERTICES 10 UNDIRECTEED NB DE EDGES 13 vertex 32426192 is L1T1 boost id 0 nb edges 5 vertex 32429496 is L1T2 boost id 1 nb edges 4 vertex 32432404 is L1T3 boost id 2 nb edges 1 vertex 32434028 is L1T4 boost id 3 nb edges 1 vertex 32435652 is L1T5 boost id 4 nb edges 1 vertex 32438816 is L2T1 boost id 5 nb edges 2 vertex 32440868 is L2T2 boost id 6 nb edges 6 vertex 32445060 is L2T3 boost id 7 nb edges 2 vertex 32446684 is L2T4 boost id 8 nb edges 2 vertex 32448308 is L2T5 boost id 9 nb edges 2 edge from L1T1 to L2T1 edge from L1T1 to L2T2 edge from L1T1 to L2T3 edge from L1T1 to L2T4 edge from L1T1 to L2T5 edge from L1T2 to L1T3 edge from L1T2 to L1T4 edge from L1T2 to L1T5 edge from L1T2 to L2T2 edge from L2T1 to L2T2 edge from L2T2 to L2T3 edge from L2T2 to L2T4 edge from L2T2 to L2T5 BOOST GRAPH DESSCRIPTION using internal ids 0 <--> 5 6 7 8 9 1 <--> 2 3 4 6 2 <--> 1 3 <--> 1 4 <--> 1 5 <--> 0 6 6 <--> 0 1 5 7 8 9 7 <--> 0 6 8 <--> 0 6 9 <--> 0 6 BOOST GRAPH DESSCRIPTION using my ids 32426192 <--> 32438816 32440868 32445060 32446684 32448308 32429496 <--> 32432404 32434028 32435652 32440868 32432404 <--> 32429496 32434028 <--> 32429496 32435652 <--> 32429496 32438816 <--> 32426192 32440868 32440868 <--> 32426192 32429496 32438816 32445060 32446684 32448308 32445060 <--> 32426192 32440868 32446684 <--> 32426192 32440868 32448308 <--> 32426192 32440868 Computing circle_graph_layout Computing kamada_kawai_spring_layout <<<<< NEVER RETURNS The code: // TYPES DECLARATIONS AND INCLUDES #include <boost/utility.hpp> #include <boost/graph/graph_utility.hpp> #include <boost/graph/random.hpp> #include <boost/pending/indirect_cmp.hpp> enum vertex_id_t { vertex_id = 500 }; enum edge_id_t { edge_id = 501 }; enum vertex_position_t { vertex_position = 502 }; namespace boost { BOOST_INSTALL_PROPERTY(vertex, id); BOOST_INSTALL_PROPERTY(edge, id); BOOST_INSTALL_PROPERTY(vertex, position); } struct point { double x; double y; }; #include <boost/graph/adjacency_list.hpp> typedef boost::adjacency_list< boost::vecS , boost::vecS , boost::undirectedS , boost::property<vertex_id_t, int , boost::property<vertex_position_t, point> > , boost::property<edge_id_t, int> > Graph; typedef boost::property<vertex_id_t, int> VertexId; typedef boost::property<edge_id_t, int> EdgeID; #include <boost/graph/fruchterman_reingold.hpp> #include <boost/graph/random_layout.hpp> #include <boost/graph/kamada_kawai_spring_layout.hpp> #include <boost/graph/circle_layout.hpp> #include <boost/graph/adjacency_list.hpp> #include <boost/random/linear_congruential.hpp> // #include <boost/test/minimal.hpp> #include <iostream> #include <boost/limits.hpp> // CODE TO COMPUTE THE LAYOUT Extract::Graph gr; // this is my own graph representation // feeds gr .... std::cout << " NB DE VERTICES " << gr.Vertices.size() << std::endl; std::cout << " NB DE EDGES " << gr.Edges.size() << std::endl; if ( gr.Edges.size() ) { Graph g; // boost graph Extract::Graph::Undirected undirected_graph(gr); std::cout << " UNDIRECTEED NB DE VERTICES " << undirected_graph.Vertices.size() << std::endl; std::cout << " UNDIRECTEED NB DE EDGES " << undirected_graph.Edges.size() << std::endl; boost::property_map<Graph, vertex_id_t>::type vertex_id_map = get(vertex_id, g); // Add vertices to boost graph int vertex_internal_id = 0; for (Extract::Graph::Undirected::tVertices::iterator elt = undirected_graph.Vertices.begin() , stop = undirected_graph.Vertices.end() ; elt != stop ; ++elt) { // boost vertex are the same as index in set add_vertex( (int)elt->first // this the memory location of my own vertice data , g ); std::cout << " vertex " << (int)elt->first << " is " << elt->first->Name->get().c_str() << " boost id " << vertex_internal_id << " nb edges " << elt->second << std::endl; elt->second = vertex_internal_id; // use map for later edge addition => we associate internal data and boost vertices ids ++vertex_internal_id; } // Add edges to boost graph int current_edge_id = 0; for (Extract::Graph::Undirected::tEdges::iterator elt = undirected_graph.Edges.begin() , stop = undirected_graph.Edges.end() ; elt != stop ; ++elt) { add_edge( undirected_graph.Vertices[*elt->begin()] // use map to get the boost vertex_internal_id for first , undirected_graph.Vertices[*elt->rbegin()] // use map to get the boost vertex_internal_id for second , 1 , g ); std::cout << " edge from " << (*elt->begin())->Name->get().c_str() << " to " << (*elt->rbegin())->Name->get().c_str() << std::endl; } std::cout << "BOOST GRAPH DESSCRIPTION using internal ids" << std::endl; print_graph(g); std::cout << "BOOST GRAPH DESSCRIPTION using my ids" << std::endl; print_graph(g,vertex_id_map); std::cout << "Computing circle_graph_layout" << std::endl; boost::circle_graph_layout( g , get(vertex_position, g) , 10.0 ); std::cout << "Computing kamada_kawai_spring_layout" << std::endl; boost::kamada_kawai_spring_layout( g , get(vertex_position, g) , get(edge_id, g) , boost::side_length(50.0) ); // THE PROGRAM NEVER RETURNS HERE <<<<<<<<<<<<<<<<<<<<<<<<<< print_graph_layout( g , get(vertex_position, g) ); }

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Re: [Boost-users] statechart::asynchronous_state_machine and state-local storage
by Tim Crews (boost) 03 Aug '08

03 Aug '08

Andreas: Thank you for your prompt responses. Also, since I neglected to do so in my initial post, thank you for the statechart library itself. I spent a considerable amount of time implementing (and, alas, debugging) a statechart library of my own in C# a few years ago. When another statechart-based project came along, and it was using C++, I was relieved to learn that your library existed. Returning to the subject at hand: The member variable that I want to share is a single boolean flag. It would only be written by "self", and only read by self's twin. There would not be any member variables that required shared read/write access. I would use the provisions of the Boost thread library to ensure that these accesses were thread-safe, as Igor suggested. But these are moot points if the framework makes such access impossible by design. Given the limited amount of data involved, it will be easy to implement the required communication using an event as you advised. Thanks again, Tim Crews GECO, Inc. >> You can't, see above. Two asynchronous state machine must only exchange >> data in >> a, well, asynchronous manner. That is, have the requesting state machine >> post >> an event to the other FSM, which in turn posts the requested data in an >> event >> back to the requesting FSM. Of course you'll have to be careful to always >> *copy* the data and never let both state machines access the same data >> through >> e.g. pointers. > <snip> It depends on how long the lock is taken by each FSM. If we're just talking lock, read/write, unlock then no I don't think you'd have any problems with just two FSMs. The longer the lock is taken the more could shared data access become a bottleneck and adversely affect performance. Of course, for Tims problem (access of state-local data), this is not a good solution as it would inevitably make the data non-local. Regards, -- Andreas Huber When replying by private email, please remove the words spam and trap from the address shown in the header.

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boost::variant as class member - linker error
by Kevin Martin 02 Aug '08

02 Aug '08

I'm new to boost::variant and I can't seem to use it in a class because I get linker errors. I can't find any reference to this in the archive or the docs so I figure it must be something silly I'm missing. Any help appreciated. The compilation command, error, and files are shown below. Thanks, Kevin Martin g++ -I $BOOSTINC test.cpp a.cpp /usr/lib64/gcc-lib/x86_64-suse-linux/3.3.5/../../../../x86_64-suse- linux/bin/ld: ` .gnu .linkonce .t ._ZN5boost6detail7variant15visitation_implIN4mpl_4int_ILi0EEENS1_20visitation_impl_stepINS_3mpl6l_iterINS7_6l_itemINS3_5long_ILl2EEEiNS9_INSA_ILl1EEESsNS7_5l_endEEEEEEENS8_ISD_EEEENS1_9destroyerEPvNS_7variantIiSsNS1_5void_ESM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_E18has_fallback_type_EEEN7Visitor11result_typeEiiRSP_T2_NS3_5bool_ILb0EEET3_PT_PT0_ ' referenced in section `.rodata' of /tmp/ccZwRSZE.o: defined in discarded section ` .gnu .linkonce .t ._ZN5boost6detail7variant15visitation_implIN4mpl_4int_ILi0EEENS1_20visitation_impl_stepINS_3mpl6l_iterINS7_6l_itemINS3_5long_ILl2EEEiNS9_INSA_ILl1EEESsNS7_5l_endEEEEEEENS8_ISD_EEEENS1_9destroyerEPvNS_7variantIiSsNS1_5void_ESM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_SM_E18has_fallback_type_EEEN7Visitor11result_typeEiiRSP_T2_NS3_5bool_ILb0EEET3_PT_PT0_ ' of /tmp/ccZwRSZE.o The files are: ==== a.h ==== #ifndef __A_HEADER__ #define __A_HEADER__ #include <boost/variant.hpp> #include <string> class A { boost::variant<int, std::string> a; public: void setToString(const std::string &x); void setToInt(int x); int which() const; }; #endif ==== a.cpp ==== #include "a.h" int A::which() const { return this->a.which(); } void A::setToString(const std::string &x) { this->a = x; } void A::setToInt(int x) { this->a = x; } ==== test.cpp ==== #include "a.h" #include <iostream> int main() { A a; a.setToString("abc"); std::cout << a.which() << std::endl; a.setToInt(123); std::cout << a.which() << std::endl; return 0; }

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FW: statechart::asynchronous_state_machine and state-local storage
by Tim Crews (boost) 02 Aug '08

02 Aug '08

Hello: I have two instances of the same state machine, which are launched as asynchronous_state_machines. I also have some state-local storage in these state machines that I would like to be able to access from outside the state machines. Actually, to be more precise, I want each instance of the state machine to be able to access a single member variable of its twin. The problem is, if I create an asynchronous state machine in the usual way (via fifo_scheduler<>::initiate_processor() and fifo_scheduler<>::operator (), it seems that the actual instance of the state machine is buried in the framework somewhere; I don't have access to a pointer to the state machine itself. Can anyone tell me how I go about getting a reference to the state machine that is instantiated when fifo_scheduler<>::initiate_processor is called? Thank you, Tim Crews GECO, Inc.

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