Function costly_adjacent

src/shk.c:5368–5381

called by sanity checking when an unpaid or no_charge item is not at a costly_spot; it might still be within the boundary of the shop; if so, those flags are still valid */

   costly_spot; it might still be within the boundary of the shop; if so,
   those flags are still valid */
boolean
costly_adjacent(
    struct monst *shkp,
    coordxy x, coordxy y)
{
    struct eshk *eshkp;

    if (!shkp || !inhishop(shkp) || !isok(x, y))
        return FALSE;
    eshkp = ESHK(shkp);
    /* adjacent if <x,y> is a shop wall spot, including door;
       also treat "free spot" one step inside the door as adjacent */
    return (levl[x][y].edge || (x == eshkp->shk.x && y == eshkp->shk.y));
}

/* called by dotalk(sounds.c) when #chatting; returns obj if location
   contains shop goods and shopkeeper is willing & able to speak */