Function valid_cloud_pos

src/read.c:1068–1074

Can a stinking cloud physically exist at a certain position? * NOT the same thing as can_center_cloud. */

 * NOT the same thing as can_center_cloud.
 */
boolean
valid_cloud_pos(coordxy x, coordxy y)
{
    if (!isok(x,y))
        return FALSE;
    return ACCESSIBLE(levl[x][y].typ) || is_pool(x, y) || is_lava(x, y);
}

/* Callback for getpos_sethilite, also used in determining whether a scroll
 * should have its regular effects, or not because it was out of range.