#include <stdio.h>

/* On Linux we need to add an underscore to the name of a Fortran 77
   variable when using it from C */
#define F77_NAME(f) f##_
#define F77_CALL(f) f##_

double F77_NAME(ddot)(int *, double *, int *, double *, int *);

#define N 1000000
#define REPS 1000

double x[N], y[N];

int main()
{
    double s;
    int i, j, one, n;

    for (i = 0; i < N; i++)
	x[i] = y[i] = i + 1;
    one = 1;
    n = N;

    for (j = 0; j < REPS; j++) {
	s = F77_CALL(ddot)(&n, x, &one, y, &one);
    }

    printf("sum = %f\n", s);
    return 0;
}