[Boost-users] Another C++ inheritence/polymorphism problem

From: Welson Sun (welson_sun_at_[hidden])
Date: 2005-02-10 18:42:07

Hi, here is another problem I met:

$ g++ main.cpp
main.cpp: In member function `void
   schedule_vertex_writer<Graph>::operator()(std::ostream&, const Vertex&)
   const [with Vertex = unsigned int, Graph =
   boost::adjacency_list<boost::vecS, boost::vecS, boost::bidirectionalS,
   BasicOperator, boost::no_property, boost::no_property, boost::listS>]':
/usr/local/include/boost/graph/graphviz.hpp:264:   instantiated from `void
boost
::write_graphviz(std::ostream&, const Graph&, VertexPropertiesWriter,
EdgeProper
tiesWriter, GraphPropertiesWriter) [with Graph =
boost::adjacency_list<boost::ve
cS, boost::vecS, boost::bidirectionalS, BasicOperator, boost::no_property,
boost
::no_property, boost::listS>, VertexPropertiesWriter =
schedule_vertex_writer<bo
ost::adjacency_list<boost::vecS, boost::vecS, boost::bidirectionalS,
BasicOperat
or, boost::no_property, boost::no_property, boost::listS> >,
EdgePropertiesWrite
r = boost::default_writer, GraphPropertiesWriter = boost::default_writer]'
/usr/local/include/boost/graph/graphviz.hpp:292:   instantiated from `void
boost
::write_graphviz(std::ostream&, const Graph&, VertexWriter) [with Graph =
Graph,
 VertexWriter = schedule_vertex_writer<boost::adjacency_list<boost::vecS,
boost:
:vecS, boost::bidirectionalS, BasicOperator, boost::no_property,
boost::no_prope
rty, boost::listS> >]'
main.cpp:93:   instantiated from here
main.cpp:52: error: passing `const BasicOperator' as `this' argument of `
   virtual OperatorType* BasicOperator::getOperatorType()' discards
qualifiers

The source code is in the attachment.

Thanks!