Address of an integer

Sample Fortran usage C function
POINTER*4 (P, I)
INTEGER*4 I, J
P = LOC(J)
I = 5
CALL CENTRY(P)
PRINT *,
1  'UPDATED VALUE IN FORTRAN:', I
END
#pragma linkage (centry,FORTRAN)
#include <stdio.h>
void centry(int **x)
{
  printf("C int arg value: %d\n",**x);
  **x += 1;
}