check (int experr, const char *prefix)
{
  const char *msg = nbd_get_error ();
  int errnum = nbd_get_errno ();

  fprintf (stderr, "error: \"%s\"\n", msg);
  fprintf (stderr, "errno: %d (%s)\n", errnum, strerror (errnum));
  if (strncmp (msg, prefix, strlen (prefix)) != 0) {
    fprintf (stderr, "%s: test failed: missing context prefix: %s\n",
             progname, msg);
    exit (EXIT_FAILURE);
  }
  if (errnum != experr) {
    fprintf (stderr, "%s: test failed: "
             "expected errno = %d (%s), but got %d\n",
             progname, experr, strerror (experr), errnum);
    exit (EXIT_FAILURE);
  }
}
check (int experr, const char *prefix)
{
  const char *msg = nbd_get_error ();
  int errnum = nbd_get_errno ();

  fprintf (stderr, "error: \"%s\"\n", msg);
  fprintf (stderr, "errno: %d (%s)\n", errnum, strerror (errnum));
  if (strncmp (msg, prefix, strlen (prefix)) != 0) {
    fprintf (stderr, "%s: test failed: missing context prefix: %s\n",
             progname, msg);
    exit (EXIT_FAILURE);
  }
  if (errnum != experr) {
    fprintf (stderr, "%s: test failed: "
             "expected errno = %d (%s), but got %d\n",
             progname, experr, strerror (experr), errnum);
    exit (EXIT_FAILURE);
  }
}