NAG Library Manual, Mark 29.1
Interfaces:  FL   CL   CPP   AD 

NAG CL Interface Introduction
Example description
/* nag_specfun_bessel_k1_scaled (s18cdc) Example Program.
 *
 * Copyright 2023 Numerical Algorithms Group.
 *
 * Mark 29.1, 2023.
 */

#include <nag.h>
#include <stdio.h>

int main(void) {
  Integer exit_status = 0;
  double x, y;
  NagError fail;

  INIT_FAIL(fail);

  /* Skip heading in data file */
  scanf("%*[^\n]");
  printf("nag_specfun_bessel_k1_scaled (s18cdc) Example Program Results\n");
  printf("     x           y\n");
  while (scanf("%lf", &x) != EOF)
  {
    /* nag_specfun_bessel_k1_scaled (s18cdc).
     * Scaled modified Bessel function exp(x) K_1(x)
     */
    y = nag_specfun_bessel_k1_scaled(x, &fail);
    if (fail.code != NE_NOERROR) {
      printf("Error from nag_specfun_bessel_k1_scaled (s18cdc).\n%s\n",
             fail.message);
      exit_status = 1;
      goto END;
    }
    printf("%12.3e%12.3e\n", x, y);
  }

END:
  return exit_status;
}