yp_first
int yp_first(char *indomain, char *inmap, char **outkey, int *outkeylen,
rv = yp_first(st->domain, map, &st->key,
rv = yp_first(st->domain, map, &st->key,
if (yp_first(ypdomain, "shells", &key, &keylen, &data, &datalen))
rv = yp_first(st->yp_domain, "services.byname",
rv = yp_first(st->domain, "rpc.bynumber",