Long floating-point number

Sample C usage (by Value) Fortran function

#pragma linkage (cfort,FORTRAN)
#include <stdio.h>
double cfort(double);
main()
{
  double x, y;
  x=12.5;
  y=cfort(x);
  printf
    ("Value returned to C: %f\n", y);
}

FUNCTION CFORT ( ARG )
REAL*8 CFORT
REAL*8 ARG
PRINT *, 'FORTRAN ARG VALUE:', ARG
CFORT = ARG
END

Sample C usage (by Reference) Fortran function

#pragma linkage (cfort,FORTRAN)
#include <stdio.h>
double cfort(double *);
main()
{
  double x, y;
  x=12.5;
  y=cfort(&x);
  printf
    ("Value returned to C: %f\n", y);
}

FUNCTION CFORT ( ARG )
REAL*8 CFORT
REAL*8 ARG
PRINT *, 'FORTRAN ARG VALUE:', ARG
CFORT = ARG
END