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boost link error
by Pervez, Salman 20 Mar '12

20 Mar '12

Hi everyone, I need some help debugging a link error I am getting. I am trying to compile an application that uses boost, here is the error. g++ -g -O2 -o .libs/sesame sesame-SysAgent.o sesame-Sysimage.o sesame-Package.o -L/home/spervez1/db-4.6.21/build_unix/lib -L/home/spervez1/boost_1_49_0/lib\ /home/spervez1/qpidc-0.14/src/.libs/libqmf.so /home/spervez1/qpidc-0.14/src/.libs/libqmfengine.so /home/spervez1/qpidc-0.14/src/.libs/libqpidclient.so /hom\ e/spervez1/qpidc-0.14/src/.libs/libqpidcommon.so -lboost_program_options -lboost_filesystem -ldl /home/spervez1/qpidc-0.14/src/.libs/libqpidtypes.so -luuid \ /home/spervez1/dbus-1.4.16/dbus/.libs/libdbus-1.so -lpthread -lrt -Wl,--rpath -Wl,/home/spervez1/qpid-tools/lib -Wl,--rpath -Wl,/home/spervez1/dbus-1.4.16/\ lib /usr/bin/ld: warning: libboost_system.so.1.49.0, needed by /home/spervez1/boost_1_49_0/lib/libboost_filesystem.so, not found (try using -rpath or -rpath-link) /home/spervez1/qpidc-0.14/src/.libs/libqpidcommon.so: undefined reference to `boost::system::system_category()' /home/spervez1/qpidc-0.14/src/.libs/libqpidcommon.so: undefined reference to `boost::system::generic_category()' collect2: ld returned 1 exit status I have boost installed in /home/spervez1/boost_1_49_0/ Here are the two commands that led to this error CPPFLAGS="-I/home/spervez1/db-4.6.21/build_unix/include -I/home/spervez1/boost_1_49_0/include" LDFLAGS="-L/home/spervez1/db-4.6.21/build_unix/lib -L/home/spervez1/boost_1_49_0/lib" ./configure --with-qpid-checkout=/home/spervez1/qpidc-0.14 --with-db4-devel=/home/spervez1/db-4.6.21/build_unix --with-boost=/home/spervez1/boost_1_49_0/ make I've researched some online and others have been able to solve this problem by adding the -lboost_filesystem flag which already exists in the makefile command so I'm a bit confused what the error could be. I'll appreciate any input on this. Thanks. Salman ________________________________ CONFIDENTIALITY AND SECURITY NOTICE The contents of this message and any attachments may be confidential and proprietary and also may be covered by the Electronic Communications Privacy Act. This message is not intended to be used by, and should not be relied upon in any way, by any third party. If you are not an intended recipient, please inform the sender of the transmission error and delete this message immediately without reading, disseminating, distributing or copying the contents. Citadel makes no assurances that this e-mail and any attachments are free of viruses and other harmful code.

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some simple questions on Date/Time parsing and formatting
by John M. Dlugosz 20 Mar '12

20 Mar '12

The Boost function ptime from_iso_string seems to only take part of a ISO 8601 date string. In particular, strings coming from XML will have a trailing Z. Even knowing that we will always get 'Z' and not some arbitrary timezone information, it seems a kludge to truncate the last character from the string before feeding it to a function that claims to parse an ISO date/time string. Am I missing something? Second, is there a simple function to format a ptime using the conventions of the current Locale? I see functions for "simple" and "iso", but user-facing output (as opposed to creating an XML file) needs to use local conventions. Thanks, —John

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[Graph] Example: astar_search_no_init over an infinite, implicit graph
by Luke Meyers 20 Mar '12

20 Mar '12

Having finally gotten this working, I wanted to share it. As the topic states, this is an implementation of an infinite, implicit graph, and an example that searches the graph with astar_search_no_init. I didn't find any examples out there of anyone doing this particular thing, so I hope it may be helpful to my fellow travelers. This code is a bastardization of some stuff from a game I'm working on (blatant plug: http://snarglequest.blogspot.com/) and the "city search" example code from the BGL docs. I'm sure it could be more concise, but I hope you'll find it accessible. Oh, and critiques would of course be welcome. I said it's working, not perfect; I'm sure there are many things I could be doing in better ways, and I'd love to know about them. Luke /** * Example use of boost::astar_search_no_init on an infinite, implicitly-defined graph. * * The graph type used here is XYGraph, representing an infinite grid of squares. Each * square is connected to its eight neighbors; however, the example shows how to use * boost::filtered_graph to make the search take place only along orthogonal edges. */ #include <iostream> #include <list> #include <map> #include <set> #include <utility> #include <boost/graph/graph_traits.hpp> #include <boost/graph/astar_search.hpp> #include <boost/graph/filtered_graph.hpp> #include <boost/operators.hpp> #include <boost/ref.hpp> namespace Direction { enum id { MIN = 0, N = MIN, S, E, W, NW, NE, SE, SW, NONE }; } struct XY : public boost::additive<XY, boost::totally_ordered<XY, boost::equivalent<XY> > > { typedef int X; typedef int Y; XY(X x = 0, Y y = 0); // Same square counts. bool adjacentTo(XY const& that) const; XY & operator=(XY const& that); XY & operator+=(XY const& that); bool operator<(XY const& that) const; X x; Y y; XY neighbor(Direction::id direction) const; std::set<XY> allNeighbors() const; }; std::ostream & operator<<(std::ostream & os, XY const& xy); struct neighbor_iterator; /* * Model of: * * Graph * * IncidenceGraph */ struct XYGraph { XYGraph(); // Graph concept requirements typedef XY vertex_descriptor; typedef std::pair<XY, XY> edge_descriptor; typedef boost::undirected_tag directed_category; typedef boost::disallow_parallel_edge_tag edge_parallel_category; typedef boost::incidence_graph_tag traversal_category; // IncidenceGraph concept requirements typedef neighbor_iterator out_edge_iterator; typedef int degree_size_type; }; namespace boost { template <> struct graph_traits<XYGraph> { typedef XYGraph G; typedef G::vertex_descriptor vertex_descriptor; typedef G::edge_descriptor edge_descriptor; typedef G::out_edge_iterator out_edge_iterator; typedef G::directed_category directed_category; typedef G::edge_parallel_category edge_parallel_category; typedef G::traversal_category traversal_category; typedef G::degree_size_type degree_size_type; typedef void in_edge_iterator; typedef void vertex_iterator; typedef void vertices_size_type; typedef void edge_iterator; typedef void edges_size_type; }; } // IncidenceGraph concept requirements std::pair<XYGraph::out_edge_iterator, XYGraph::out_edge_iterator> out_edges(XYGraph::vertex_descriptor v, XYGraph const& g); XYGraph::degree_size_type out_degree(XYGraph::vertex_descriptor v, XYGraph const& g); XYGraph::vertex_descriptor source(XYGraph::edge_descriptor e, XYGraph const& g); XYGraph::vertex_descriptor target(XYGraph::edge_descriptor e, XYGraph const& g); // Iterator struct neighbor_iterator : public boost::iterator_facade<neighbor_iterator, std::pair<XY,XY>, boost::forward_traversal_tag, std::pair<XY,XY> > { public: neighbor_iterator(); neighbor_iterator(XY xy, Direction::id direction); neighbor_iterator & operator=(neighbor_iterator const& that); std::pair<XY,XY> operator*() const; void operator++(); bool operator==(neighbor_iterator const& that) const; bool equal(neighbor_iterator const& that) const { return operator==(that); } void increment() { operator++(); } private: XY xy; Direction::id direction; }; struct orthogonal_only; template <typename Graph> class distance_heuristic; struct found_goal {}; // exception for termination // visitor that terminates when we find the goal class astar_goal_visitor : public boost::default_astar_visitor { public: astar_goal_visitor(XY goal) : m_goal(goal) {} virtual void examine_vertex(XY xy, XYGraph const& g) { std::cout << "Exploring " << xy << "..." << std::endl; if(xy == m_goal) throw found_goal(); } virtual void examine_vertex(XY xy, boost::filtered_graph<XYGraph, orthogonal_only> const& g) { std::cout << "Exploring " << xy << "..." << std::endl; if(xy == m_goal) throw found_goal(); } private: XY m_goal; }; template <typename K, typename V> class default_map { public: typedef K key_type; typedef V data_type; typedef std::pair<K,V> value_type; default_map(V const& defaultValue) : defaultValue(defaultValue) {} V & operator[](K const& k) { if (m.find(k) == m.end()) { m[k] = defaultValue; } return m[k]; } private: std::map<K,V> m; V const defaultValue; }; struct PredecessorMap { PredecessorMap() {} PredecessorMap(PredecessorMap const& that) : m(that.m) {} typedef XY key_type; typedef XY value_type; typedef XY & reference_type; typedef boost::read_write_property_map_tag category; XY & operator[](XY xy) { return m[xy]; } std::map<XY,XY> m; }; XY get(PredecessorMap const& pm, XY xy) { std::map<XY,XY>::const_iterator found = pm.m.find(xy); return (found != pm.m.end()) ? found->second : xy; } void put(PredecessorMap & pm, XY key, XY value) { pm.m[key] = value; } // Filter used to traverse grid only along orthogonal (non-diagonal) edges. struct orthogonal_only { typedef std::pair<XY,XY> Edge; bool operator()(Edge const& edge) const { return edge.first.x == edge.second.x || edge.first.y == edge.second.y; } }; // Euclidean distance heuristic (square root omitted) template <typename Graph> class distance_heuristic : public boost::astar_heuristic<Graph, int> { public: distance_heuristic(XY goal) : m_goal(goal) {} unsigned operator()(XY xy) { int dx = m_goal.x - xy.x; int dy = m_goal.y - xy.y; unsigned retval = static_cast<unsigned>(dx * dx + dy * dy); return retval; } private: XY m_goal; }; int main(int argc, char **argv) { XYGraph baseGraph; boost::filtered_graph<XYGraph, orthogonal_only> g(baseGraph, orthogonal_only()); //BOOST_CONCEPT_ASSERT((IncidenceGraphConcept< boost::filtered_graph<XYGraph, orthogonal_only> >)); XY start(0,0); XY goal(5,7); std::cout << "Start vertex: " << start << std::endl; std::cout << "Goal vertex: " << goal << std::endl; PredecessorMap p; typedef boost::associative_property_map< default_map<XY,unsigned> > DistanceMap; typedef default_map<XY,unsigned> WrappedDistanceMap; WrappedDistanceMap wrappedMap = WrappedDistanceMap(std::numeric_limits<unsigned>::max()); wrappedMap[start] = 0; DistanceMap d = DistanceMap(wrappedMap); try { astar_search_no_init(g, start, distance_heuristic<XYGraph>(goal) , visitor(astar_goal_visitor(goal)) . distance_map(d) . predecessor_map(boost::ref(p)) . weight_map(boost::associative_property_map< default_map<std::pair<XY,XY>,unsigned> >( default_map<std::pair<XY,XY>,unsigned>(1))) . vertex_index_map(boost::associative_property_map< std::map<XY,unsigned> >(std::map<XY,unsigned>())) . rank_map(boost::associative_property_map< std::map<XY,unsigned> >(std::map<XY,unsigned>())) . color_map(boost::associative_property_map< std::map<XY,boost::default_color_type> >( std::map<XY,boost::default_color_type>())) . distance_compare(std::less<unsigned>()) . distance_combine(std::plus<unsigned>()) ); } catch(found_goal const&) { // found a path to the goal std::list<XY> shortest_path; for(XY xy = goal;; xy = p[xy]) { shortest_path.push_front(xy); if(p[xy] == xy) break; } std::cout << "Shortest path from " << start << " to " << goal << ": "; std::list<XY>::iterator spi = shortest_path.begin(); std::cout << start; for(++spi; spi != shortest_path.end(); ++spi) std::cout << " -> " << (*spi); std::cout << std::endl; return 0; } std::cout << "Didn't find a path from " << start << "to" << goal << "!" << std::endl; return 0; } XYGraph::XYGraph() {} std::pair<XYGraph::out_edge_iterator, XYGraph::out_edge_iterator> out_edges(XYGraph::vertex_descriptor v, XYGraph const& g) { return std::make_pair( XYGraph::out_edge_iterator(v, Direction::MIN), XYGraph::out_edge_iterator(v, Direction::NONE) ); } XYGraph::degree_size_type out_degree(XYGraph::vertex_descriptor v, XYGraph const& g) { return v.allNeighbors().size(); } XYGraph::vertex_descriptor source(XYGraph::edge_descriptor e, XYGraph const& g) { return e.first; } XYGraph::vertex_descriptor target( XYGraph::edge_descriptor e, XYGraph const& g) { return e.second; } neighbor_iterator::neighbor_iterator() {} neighbor_iterator::neighbor_iterator(XY xy, Direction::id direction) : xy(xy) , direction(direction) { } neighbor_iterator & neighbor_iterator::operator=(neighbor_iterator const& that) { xy = that.xy; direction = that.direction; return *this; } std::pair<XY,XY> neighbor_iterator::operator*() const { std::pair<XY,XY> const retval = std::make_pair(xy, xy.neighbor(direction)); return retval; } void neighbor_iterator::operator++() { direction = static_cast<Direction::id>(int(direction) + 1); } bool neighbor_iterator::operator==(neighbor_iterator const& that) const { return xy == that.xy && direction == that.direction; } XY::XY(X x, Y y) : x(x) , y(y) { } bool XY::adjacentTo(XY const& that) const { return abs(x - that.x) <= 1 && abs(y - that.y) <= 1; } XY & XY::operator=(XY const& that) { x = that.x; y = that.y; return *this; } XY & XY::operator+=(XY const& that) { x += that.x; y += that.y; return *this; } bool XY::operator<(XY const& that) const { return x < that.x || (x == that.x && y < that.y); } std::ostream & operator<<(std::ostream & os, XY const& xy) { os << "(" << xy.x << "," << xy.y << ")"; return os; } XY XY::neighbor(Direction::id direction) const { using namespace Direction; int dx = 0, dy = 0; switch (direction) { case NW: case W: case SW: dx = -1; break; case NE: case E: case SE: dx = 1; } switch (direction) { case NW: case N: case NE: dy = -1; break; case SW: case S: case SE: dy = 1; } XY const neighbor(x + dx, y + dy); return neighbor; } std::set<XY> XY::allNeighbors() const { std::set<XY> neighbors; for (int dx = -1; dx <= 1; ++dx) for (int dy = -1; dy <= 1; ++dy) neighbors.insert(XY(x+dx,y+dy)); return neighbors; }

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Tokenizer - multiple separators
by asif saeed 20 Mar '12

20 Mar '12

Hi, Can I pass multiple separators (for example ";|") in a char_sep to Boost::Tokenizer? Can I then use boost is_any_of to tokenize of any of these separator characters? Can you give me an example? Does Boost::Tokenizer already do this? Thanks in advance. Best regards, Asif

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[XML] validate closing tags with boost property tree read_xml?
by Simon Coakley 20 Mar '12

20 Mar '12

boost::property_tree::xml_parser::read_xml uses the default rapidxml behaviour of not validating closing tags. With rapidxml you can use the flag parse_validate_closing_tags to turn this on. Boost does not support any such flag. Is there anyway to turn it on using Boost or will I have to use rapidxml directly? Thanks

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Status of move semantics with boost::optional
by mark pashley 20 Mar '12

20 Mar '12

Rvalue references and Move semantics are a major C++11 feature that can significantly speed up code by reducing unnecessary copies. The STL has been updated to use this new feature when a c++11/0x compiler is used (e.g. gcc 4.6) I stumbled across this ticket : https://svn.boost.org/trac/boost/ticket/1841 which discusses the addition of move semantics to boost::optional. Is there any news on when the boost::optional library will support move semantics? I am primarily interested in using this library with a c++11/0x compiler (e.g. GCC 4.6). -- View this message in context: http://boost.2283326.n4.nabble.com/Status-of-move-semantics-with-boost-opti… Sent from the Boost - Users mailing list archive at Nabble.com.

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[Graph] filtered_graph of IncidenceGraph is not an IncidenceGraph
by Luke Meyers 20 Mar '12

20 Mar '12

Hello, list. First time poster, sometime reader. Today I finally achieved a milestone I've been working towards in my BGL-oriented project: I got astar_search_no_init working on an implicit graph. Now I want to filter the input graph to restrict the search, and I'm running into trouble with filtered_graph. My implicit graph class is a model of IncidenceGraph, as required by astar_search_no_init, but when I apply filtered_graph to it I find that the result is no longer an IncidenceGraph (according to BOOST_CONCEPT_ASSERT). The filtered_graph documentation saith: If the underlying Graph type models VertexAndEdgeListGraph and > PropertyGraph then so does the filtered graph. If the underlying Graph type > models fewer or smaller concepts than these, then so does the filtered > graph. >From this, I would assume that if I run filtered_graph on an IncidenceGraph, the result will be a model of IncidenceGraph, not just of Graph. Also, if my input is an IncidenceGraph and not a VertexAndEdgeListGraph, I'd hope compilation would not fail if I don't have graph_traits defined for types required by VertexAndEdgeListGraph, but it does: c:\src\boost_1_49_0\boost\graph\filtered_graph.hpp(181) : error C2039: > 'in_edge_iterator' : is not a member of 'boost::graph_traits<XYGraph>' When I provide a bunch of dummy typedefs to get around this error, I can get to the point of doing a BOOST_CONCEPT_ASSERT((IncidenceGraphConcept<* FilteredGraphType*>)). This fails: c:\src\boost_1_49_0\boost\graph\graph_concepts.hpp(94) : error C2679: > binary '=' : no operator found which takes a right-hand operand of type > 'XY' (or there is no acceptable conversion) XY here is my vertex descriptor type. The edge descriptor is a pair<XY,XY>, but for some reason it's getting XY out of the graph_traits instead and failing in this strange way. Am I missing something? Are my expectations incorrect? Is this actually a bug (or two)? At the bottom is a decently small example that fails for me (some function bodies excised for brevity -- my concerns are pre-link). Is there a way to work around this without making my graph into a model of VertexAndEdgeListGraph? Since my graph is infinite, this would hardly seem sensible. Thanks in advance for any assistance. Incidentally, if anyone's interested to see a working example of astar_search_no_init over an implicit graph, I'd be happy to clean up the code a little and post it. Luke Project blog (SnargleQuest, a Roguelike game): http://snarglequest.blogspot.com/ // Code listing #include <iostream> #include <list> #include <map> #include <set> #include <utility> #include <boost/graph/filtered_graph.hpp> #include <boost/graph/graph_concepts.hpp> #include <boost/graph/graph_traits.hpp> #include <boost/operators.hpp> using namespace boost; using namespace std; namespace Direction { enum id { MIN = 0, N = MIN, S, E, W, NW, NE, SE, SW, NONE, NUM_DIRECTIONS }; } struct XY : public boost::additive<XY, boost::totally_ordered<XY, boost::equivalent<XY> > > { typedef int X; typedef int Y; XY(X x = 0, Y y = 0); XY & operator=(XY const& that); XY & operator+=(XY const& that); bool operator<(XY const& that) const; X x; Y y; }; std::ostream & operator<<(std::ostream & os, XY const& xy); struct neighbor_iterator; /* * Model of: * * Graph * * IncidenceGraph */ struct XYGraph { XYGraph(); // Graph concept requirements typedef XY vertex_descriptor; typedef std::pair<XY, XY> edge_descriptor; typedef undirected_tag directed_category; typedef disallow_parallel_edge_tag edge_parallel_category; typedef incidence_graph_tag traversal_category; // IncidenceGraph concept requirements typedef neighbor_iterator out_edge_iterator; typedef int degree_size_type; }; // IncidenceGraph concept requirements std::pair<XYGraph::out_edge_iterator, XYGraph::out_edge_iterator> out_edges(XYGraph::vertex_descriptor v, XYGraph const& g); XYGraph::degree_size_type out_degree(XYGraph::vertex_descriptor v, XYGraph const& g); XYGraph::vertex_descriptor source(XYGraph::edge_descriptor e, XYGraph const& g); XYGraph::vertex_descriptor target(XYGraph::edge_descriptor e, XYGraph const& g); // Iterator struct neighbor_iterator : public boost::forward_iterator_helper<neighbor_iterator, XY, std::ptrdiff_t, XY *, XY> { public: neighbor_iterator(); neighbor_iterator(XY xy, Direction::id direction); neighbor_iterator & operator=(neighbor_iterator const& that); std::pair<XY,XY> operator*() const; void operator++(); bool operator==(neighbor_iterator const& that) const; }; namespace boost { template <> struct graph_traits<XYGraph> { typedef XYGraph G; typedef G::vertex_descriptor vertex_descriptor; typedef G::edge_descriptor edge_descriptor; typedef G::out_edge_iterator out_edge_iterator; typedef G::directed_category directed_category; typedef G::edge_parallel_category edge_parallel_category; typedef G::traversal_category traversal_category; typedef G::degree_size_type degree_size_type; // Shouldn't have to do this! typedef void in_edge_iterator; typedef void vertex_iterator; typedef void vertices_size_type; typedef void edge_iterator; typedef void edges_size_type; }; } struct orthogonal_only { typedef pair<XY,XY> Edge; bool operator()(Edge const& edge) { return edge.first.x == edge.second.x || edge.first.y == edge.second.y; } }; int main(int argc, char **argv) { BOOST_CONCEPT_ASSERT((IncidenceGraphConcept<XYGraph>)); // This fails BOOST_CONCEPT_ASSERT((IncidenceGraphConcept< filtered_graph<XYGraph, orthogonal_only> >)); return 0; }

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boost::noncopyable - I see
by John M. Dlugosz 20 Mar '12

20 Mar '12

The compiler (VS10) generates this when the copy constructor is used somewhere by mistake. It doesn't tell me where the offending use is, unlike putting a private dummy declaration right in the class. So it did its job, but is most unfriendly about it.

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[Iterator] shared_container_iterator usability
by Szymon Gatner 19 Mar '12

19 Mar '12

Hello boosters, a design question: how often (if ever) and under which circumstances do you use shared_container_iterator? (http://www.boost.org/doc/libs/1_49_0/libs/utility/shared_container_iterator…) I don't feel too good about allocating a vector<> on the heap but I guess it was made for some reason and motivated by actuall need. What are good use cases for such iterator? Obviously returning a container from function (as presented in example) is not one of them. Cheers, Simon

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Thread safety in Boost.Test
by Eric Teutsch 19 Mar '12

19 Mar '12

I found this article from 2003. http://lists.boost.org/Archives/boost/2003/02/44515.php I gather that 9 years later, Boost.Test is still not thread-safe (at least it's still on the To-Do list). Can somebody explain what BOOST_TEST_THREAD_SAFE accomplishes? Thanks, Eric T This message, and the documents attached hereto, is intended only for the addressee and may contain privileged or confidential information. Any unauthorized disclosure is strictly prohibited. If you have received this message in error, please notify us immediately so that we may correct our internal records. Please then delete the original message. Thank you.

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