can't patch rpm.c

[turhan mehmet <sokullu ultratv net>]

Hi people,

I want to make a patch to rpm.c
I want to call a python program after rpm installations. So I try this 
simple patch:

@@  rpm.c ;  int main(..) function
   ..
   ..
   case MODE_INSTALL:
   ..
+ system("/path/to/mysmallpythonapp.py");       #// my small patch
   break;


Here you have seen my simple patch. I tried not just system() function 
but also the simplest ones like puts(), fprintf() etc. but they don't work!!

I didn't understand, what's the problem here??

I even tried to add this small code additions just before the end of the 
main function.

I'm not a experienced C programmer and I just can say; "Please help!"
Thanx in advance..