SWIG and Cython

Overall, if you consider SWIG (http://swig.org/) as a way to write a native Python module, you could be fooled to think that Cython and SWIG are similar. SWIG is mainly used to write wrappers for language bindings. For example, if you have some C code as follows:

int myFunction (int, const char *){ … }

You can write the SWIG interface file as follows:

/* example.i */
%module example
%{
  extern int myFunction (int, const char *);
...
%}

Compile this with the following:

$ swig -python example.i

You can compile and link the module as you would do for a Cython output since this generates the necessary C code. This is fine if you want a basic module to simply call into C from Python. But Cython provides users with much more.

Cython is much more developed and optimized, and it truly understands how to work with C types and memory management and how to handle exceptions. With SWIG, you cannot manipulate data; you simply call into functions on the C side from Python. In Cython, we can...