exitwhen is used to specify the events which may occur within xxx, their occurrence is indicated by using the name of the event as a statement. When some event does occur, the relevant action is carried out, and then control passes just after '''. This construction provides a very clear separation between determining that some situation applies, and the action to be taken for that situation.exitwhen is conceptually similar to exception handling, and exceptions or similar constructs are used for this purpose in many languages.
exitwhen is used to specify the events which may occur within xxx their occurrence is indicated by using the name of the event as a statement When some event does occur the relevant action is carried out and then control passes just after ''' This construction provides a very clear separation between determining that some situation applies and the action to be taken for that situationexitwhen is conceptually similar to exception handling and exceptions or similar constructs are used for this purpose in many languages