https://svn.boost.org/trac10/ticket/512 <pre class="wiki">The first time I submitted I forgot to check the box for uploading the zip archive... I want to draw your attention to a possible flaw in the implementation of the write_graphviz method from the Boost Graph Library. The current implementation uses the assignment operator for the vertex and edge iterators. This is natural, but some examples fail to compile with this version. The problem comes from the predicates witch don't have default constructors. When trying to assign a vertex iterator of a graph filtered with such a predicate, the compiler issues an error: C2512:'positive_edge_weight_pred&lt;MyEdgeWeightMap&gt;' : no appropriate default constructor available with [ MyEdgeWeightMap=EdgeWeightMapT ] If a small modification in the write_graphviz implementation is made (using copy constructors instead of assignement operators), the example compiles and runs sucesfully. I am using the Microsoft Visual C++ 7.1 compiler. In conclusion, I think that this modification should be made, as it grows the flexibility of the library and doesn't add any overhead. I have attached the example (main.cpp) and the patch for graphviz.hpp (graphviz.hpp.patch). My e-mail adress is pdumitrache@bphx.ro </pre> en-us /htdocs/site/boost.png https://svn.boost.org/trac10/ticket/512 Trac 1.4.3 Douglas Gregor Mon, 23 Jan 2006 19:47:45 GMT https://svn.boost.org/trac10/ticket/512#comment:1 https://svn.boost.org/trac10/ticket/512#comment:1 <ul> <li><strong>status</strong> <span class="trac-field-old">assigned</span> → <span class="trac-field-new">closed</span> </li> </ul> <pre class="wiki">Logged In: YES user_id=249098 This is not a bug in write_graphviz. The predicate (in this case, positive_edge_weight_pred) must be both Default Constructible and Assignable, according to the requirements listed in the filtered_graph documentation. However, it does not meet these requirements. The bug (unfortunately) shows up in a call to write_graphviz. To correct the example, store the weight map by value or pointer in the predicate, not by reference. </pre> Ticket