It is permissible to implement this function by returning 0 to indicate that the bits were not saved and, therefore, must be saved by the calling routine.
GreCloseScreenChangeArea calls EnterDriver and performs entry checks. The function checks that the hsca field matches one of the existing SCAs. If it does, the function removes the SCA from the linked list, frees the SCA memory via FreeMem and updates the linked list.
If the SCA to be closed is the last created (that is, there are no more in the linked list), then GreSetProcessControl is called to turn off the COM_SCR_BOUND bit on subsequent calls to the display driver. Resetting this bit prevents any further screen bounds accumulation until another call is made to GreOpenScreenChangeArea.
Before returning either TRUE or FALSE, GreCloseScreenChangeArea calls ExitDriver.