Function TunnelBridgeIsFree

src/vehicle.cpp:551–565

* Finds vehicle in tunnel / bridge * @param tile first end * @param endtile second end * @param ignore Ignore this vehicle when searching * @return Succeeded command (if tunnel/bridge is free) or failed command (if a vehicle is using the tunnel/bridge). */

 * @return Succeeded command (if tunnel/bridge is free) or failed command (if a vehicle is using the tunnel/bridge).
 */
CommandCost TunnelBridgeIsFree(TileIndex tile, TileIndex endtile, const Vehicle *ignore)
{
	for (TileIndex t : {tile, endtile}) {
		/* Value v is not safe in MP games, however, it is used to generate a local
		 * error message only (which may be different for different machines).
		 * Such a message does not affect MP synchronisation.
		 */
		for (const Vehicle *v : VehiclesOnTile(t)) {
			if (v->type != VEH_TRAIN && v->type != VEH_ROAD && v->type != VEH_SHIP) continue;
			if (v == ignore) continue;
			return CommandCost(STR_ERROR_TRAIN_IN_THE_WAY + v->type);
		}
	}
	return CommandCost();
}

/**
 * Tests if a vehicle interacts with the specified track bits.