Re: how do you send a fortran character string from GCC to GFortran ?

On Thu, 02 Jan 2025 02:27:54 -0600, Lynn McGuire wrote:
 

How do you send a fortran character string from GCC to GFortran ?
>
I cannot get this to link.  I can do the reverse, send a fortran
character string from Gfortran to GCC.
>
I do have the additional complication that I do not know the length of
the fortran character string being sent from GCC to Gfortran at compile
time, only run time.  So that is a character*(*) string.
>
I am not using the ISO C binding.

 As Thomas as indicated, ISO C binding was introduced into the
Fortran standard to address your needs.  But, if you want to
go old school with gcc/gfortran, then
 % cat aa.c
#include <string.h>
 void
string_(char *s, int *slen)
{
    strncpy(s, "abc", *slen);
}
 % cat bb.f90
program foo
    external :: string
    character(len=10) str
    call string(str, len(str))
    print *, '>>' // str //'<<'
end program foo
 % ~/work/bin/gcc -c aa.c
% gfcx -o z bb.f90 aa.o
% ./z
  >>abc<<