#include "foo.h" int csub(int arg) { return (2*arg); } int fwrapper(int arg) { int res; printf("Calling the Fortran 77 subroutine from the C wrapper...\n"); F77_FUNC(fsub,FSUB)(&arg,&res); printf("Returned from the Fortran 77 subroutine...\n"); return res; }