Function openfallingtrap

src/trap.c:6251–6289

for magic unlocking; returns true if targeted monster (which might be hero) gets hit by a trap (target might avoid its effect) */

/* for magic unlocking; returns true if targeted monster (which might
   be hero) gets hit by a trap (target might avoid its effect) */
boolean
openfallingtrap(
    struct monst *mon,
    boolean trapdoor_only,
    boolean *noticed) /* set to true iff hero notices the effect; */
{                     /* otherwise left with its previous value intact */
    struct trap *t;
    boolean ishero = (mon == &gy.youmonst), result;

    if (!mon)
        return FALSE;
    if (mon == u.usteed)
        ishero = TRUE;
    t = t_at(ishero ? u.ux : mon->mx, ishero ? u.uy : mon->my);
    /* if no trap here or it's not a falling trap, we're done
       (note: falling rock traps have a trapdoor in the ceiling) */
    if (!t || ((t->ttyp != TRAPDOOR && t->ttyp != ROCKTRAP)
               && (trapdoor_only || (t->ttyp != HOLE && !is_pit(t->ttyp)))))
        return FALSE;

    if (ishero) {
        if (u.utrap)
            return FALSE; /* already trapped */
        *noticed = TRUE;
        dotrap(t, FORCETRAP);
        result = (u.utrap != 0);
    } else {
        if (mon->mtrapped)
            return FALSE; /* already trapped */
        /* you notice it if you see the trap close/tremble/whatever
           or if you sense the monster who becomes trapped */
        *noticed = cansee(t->tx, t->ty) || canspotmon(mon);
        /* monster will be angered; mintrap doesn't handle that */
        wakeup(mon, TRUE);
        result = (mintrap(mon, FORCETRAP) != Trap_Effect_Finished);
        /* mon might now be on the migrating monsters list */
    }
    return result;
}

/* only called when the player is doing something to the chest directly;
   returns True if chest is destroyed, False if it remains in play */