Basic importing question

[Christian Heimes]

Bruno Desthuilliers wrote:
> As the name imply, built-in modules are built in the interpreter - IOW, 
> they are part of the interpreter *exposed* as modules[1]. Unless you 
> have a taste for gory implementation details, just don't worry about this.
> 
> Other "ordinary" modules need of course to be executed once when first 
> loaded - IOW, the first time they are imported. All statements[2] at the 
> top-level of the module are then sequentially executed, so that any 
> relevant object (functions, classes, whatever) are created and bound in 
> the module's namespace.

Builtin modules like thread, signal etc. as well as C extensions like 
socket have an initialization function. The initialization function is 
called during the first import of a module. It creates the module object 
and assigns objects to its __dict__ attribute.

Builtin modules are statically linked into the Python executable / 
library while normal C extensions are shared libraries. Some modules are 
builtins because they are required during boot strapping. It's possible 
to embed most C modules into the core.

Christian