I am trying to extend CGraph using C++ containers only to get a cython compile error: ambiguous overloaded method on memset, memcopy and strlen. As CGraph uses bitset which I have to manipulate, I need to include bitset.pxi and bitset.pxd.pxi, so end up with a mix of c and c++ calls for cython to deal with. I am guessing that cython can't decide which memset etc calls to use, C++ or C versions.