[capi-sig] Compiling/Linking external Functions (setup.py, distutils, gcc?)

[Philipp Heuser]

Hello all,

I would like to use an existing C-Function from python. Therfore I made 
up an wrapper (wrap.c), where all the variable transformations from 
Python to C are done. That works. Now I would like to call the external 
fuction, which is placed in lets say ext_foo.a with a corresponding 
ext_foo.h  and can be used as a library from plain C.

I am assuming, that I do have to include the ext_foo.h in my wrap.c with
#include "ext_foo.h"

that I have to introduce the function in my C-Code:

extern int foo(int);

that I have to tell the setup.py using the distutils stuff where the 
library can be found...

when compiling a C-Code which is not for python usage I do type

gcc -o test.o ./test.c ./ext_foo.a -I./foo_h_file_path/

and everything is fine,
where within these setup.py files do I have to mention the ./ext_foo.a ? 
When I do place it in the sources-tag, setup procedure complains that it 
doesn't know any .a files... if I don't mention it explicitly, just 
giving the include_dirs, compilation works fine, but when importing from 
python 'import wrap' I do get the message: Symbol not found: _foo

Any help is very much appreciated!
Thanks
Philipp