[Python-bugs-list] Re: SWIG's embed.i and Python 1.5.2 on WinNT (PR#25)

[fp@contact.de]

Hi Guido,

SWIG automatically generates scripting language bindings
for C libraries. It provides a feature to build a standalone
interpreter that contains the wrapper module and all the
standard builtin modules of Python. For that purpose the
SWIG-generated module source provides its own `main',
"grabs" Python's inittab[] structure, adds the wrapper
module, sets PyImport_Inittab to the patched inittab and
calls Py_Main(). The generated source looks like this
(with some omissions):

	#define _PyImport_Inittab swig_inittab
	/* Grab Python's inittab[] structure */

	#include <config.c> /* This is Pythons's config.c! */

	#undef _PyImport_Inittab 

	/* Now define our own version of it.
	   Hopefully someone does not have more than 1000
	   built-in modules */

	struct _inittab _SwigImport_Inittab[1000];       

	[...]

	int
	main(int argc, char **argv) {
		swig_add_builtin(); /* add wrapper module */
		PyImport_Inittab = _SwigImport_Inittab;
		return Py_Main(argc,argv);
	}

If you allow, I'd like to forward your questions to Dave Beazley
(beazley@cs.uchicago.edu), the author of SWIG.

	- frank

P.S. Sorry for the duplicate PR#26. I was braindead and
     pressed "Reload".

Guido van Rossum wrote:
> I don't think that exporting module initialization calls is the right
> solution.  I don't know SWIG -- why is it calling these functions?
> If you reference some other extension module, will it require that
> module's init function to be exported?  On Unix, will it fail if those
> extensions happen to be dynamically loaded instead of statically linked?
> 
> A better approach would be to use the PyImport_ImportModule()
> function to import the module by name.  This will find the module
> you're looking for regardless of whether it is built in or provided
> as a shared library.

-- 
Frank Patz
CONTACT Software GmbH                 email: fp@contact.de
Wiener Str. 1-3                       phone: +49 421 20153 18
D-28359 Bremen                        fax:   +49 421 20153 41