Boost.Python __init__() should return None, not 'NoneType'

Question

I have a whole bunch of working C++ code that I want to write Python bindings for. I\'m trying to use Boost.Python since it seems to be the easiest way to get this working,

Answer 1

This error is probably due to linking against the wrong Python library. Make sure your extension as well as the Boost Python library are linked against the Python installation you are using to import the module.

On Linux you can check against which libraries you've linked with ldd. On OS X otool -L does the same thing. So, for example

otool -L libpcap_ext.so
otool -L /path/to/libboost_python-mt.dylib

should list the Python library they are linked against.

With CMake you can use the variable PYTHON_LIBRARY to change which Python library is used. As an example, on the command line you can set it with

cmake -DPYTHON_LIBRARY="/path/to/libpython2.7.dylib" source_dir

Lastly, on OS X a quick and dirty way (i.e. without recompiling) to change the dynamically linked libraries is install_name_tool -change.