473:/lib/skill_raise.c (/lib/skill_raise.c)
(int) sk_hook_unknown_skill(string skill, string verb)
/*
 * Function name: sk_hook_unknown_skill
 * Description  : Player tries to improve or learn an unknown skill.
 * Arguments    : string skill - The skill he sought for.
 *                string verb  - 'learn' or 'improve'.
 * Returns      : int 0 - as always with notify_fail.
 */
