Returns 1 if the key code given was released this frame, then returns 0 whilst the key is up. This only applies to platforms with a full sized keyboard such as PC and Mac, otherwise all keys will return 0. You can check if a keyboard exists by checking GetKeyboardExists returns 1. Key codes are in the range 0 to 255, anything out of range will return 0. Check out the scan codes page in the guides section of the help files to see which key matches which key code
integer GetRawKeyReleased( key )