NAG Library Manual, Mark 29.3
```/* nag_specfun_bessel_y1_real_vector (s17arc) Example Program.
*
* Copyright 2023 Numerical Algorithms Group.
*
* Mark 29.3, 2023.
*/
#include <nag.h>
#include <stdio.h>

int main(void) {
Integer exit_status = 0;
Integer i, n;
double *f = 0, *x = 0;
Integer *ivalid = 0;
NagError fail;

INIT_FAIL(fail);

/* Skip heading in data file */
scanf("%*[^\n]");

printf(
"nag_specfun_bessel_y1_real_vector (s17arc) Example Program Results\n");
printf("\n");
printf("     x           f          ivalid\n");
printf("\n");
scanf("%" NAG_IFMT "", &n);
scanf("%*[^\n]");

/* Allocate memory */
if (!(x = NAG_ALLOC(n, double)) || !(f = NAG_ALLOC(n, double)) ||
!(ivalid = NAG_ALLOC(n, Integer))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}

for (i = 0; i < n; i++)
scanf("%lf", &x[i]);
scanf("%*[^\n]");

/* nag_specfun_bessel_y1_real_vector (s17arc).
* Bessel function Y_1(x)
*/
nag_specfun_bessel_y1_real_vector(n, x, f, ivalid, &fail);
if (fail.code != NE_NOERROR && fail.code != NW_IVALID) {
printf("Error from nag_specfun_bessel_y1_real_vector (s17arc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}

for (i = 0; i < n; i++)
printf(" %11.3e %11.3e %4" NAG_IFMT "\n", x[i], f[i], ivalid[i]);

END:
NAG_FREE(f);
NAG_FREE(x);
NAG_FREE(ivalid);

return exit_status;
}
```