### 3.3.2 Extension source files

The second argument to the `Extension` constructor is a list of source files. Since the Distutils currently only support C/C++ extensions, these are normally C/C++ source files. (Be sure to use appropriate extensions to distinguish C++ source files: .cc and .cpp seem to be recognized by both Unix and Windows compilers.)

However, you can also include SWIG interface (.i) files in the list; the `build_ext` command knows how to deal with SWIG extensions: it will run SWIG on the interface file and compile the resulting C/C++ file into your extension.

** SWIG support is rough around the edges and largely untested; especially SWIG support of C++ extensions! Explain in more detail here when the interface firms up. **

On some platforms, you can include non-source files that are processed by the compiler and included in your extension. Currently, this just means Windows resource files for Visual C++. ** get more detail on this feature from Thomas Heller! **