On most modern systems it is possible to configure Python to support
dynamic loading of extension modules implemented in C. When shared
libraries are used dynamic loading is configured automatically;
otherwise you have to select it as a build option (see below). Once
configured, dynamic loading is trivial to use: when a Python program
executes import foo, the search for modules tries to find a
file `foomodule.o' (`foomodule.so' when using shared
libraries) in the module search path, and if one is found, it is
loaded into the executing binary and executed. Once loaded, the
module acts just like a built-in extension module.
The advantages of dynamic loading are twofold: the `core' Python binary gets smaller, and users can extend Python with their own modules implemented in C without having to build and maintain their own copy of the Python interpreter. There are also disadvantages: dynamic loading isn't available on all systems (this just means that on some systems you have to use static loading), and dynamically loading a module that was compiled for a different version of Python (e.g. with a different representation of objects) may dump core.