I used SWIG to wrap my c++ class. Some methods have a const std::string& as a parameter. SWIG creates a type called SWIGTYPE_p_std__string however
const std::string&
SWIGTYPE_p_std__string
I was trying to solve this myself when I found your question.
You need to include
%include "std_string.i"
in your .i file. See:
.i
STL/C++ library
for more details.