No builtin support for std::string& in return values.

[Kevin Stenerson]

There exists support for string references as parameters, but there is no built-in support for string references as return values.
Note, in this particular case I'm mostly concerned with a type like "const std::string&".

Just for reference, in case I'm doing something completely silly, here is the end of the error output received when using retval('const std::string &')

File "/usr/lib64/python2.7/site-packages/pybindgen/typehandlers/base.py", line 1437, in lookup
    raise TypeLookupError(tried_names)
pybindgen.typehandlers.base.TypeLookupError: ['std::string &']

[Gustavo Carneiro (gjc)]

This is because it is simply not possible to return a reference to a temporary variable, at least in "reverse wrappers". Adding support for returning references is really hard. I suggest you just use std::string instead of std::string& as type. It will probably work just as well as long as you are not using it in a virtual method or attribute.