500:/lib/skill_raise.c (/lib/skill_raise.c)
(int) sk_hook_learn_known(string skill)
/*
 * Function name: sk_hook_learn_known
 * Description  : Player wants to learn an already known skill.
 * Arguments    : string skill - the skill the player tried to learn.
 * Returns      : int 0 - as always with notify_fail.
 */
