Discussion: The POPALL statement clears all return addresses from the GOSUB stack. It is used to branch directly from a nested subroutine (at any level) to the main program.
Note: If the subroutine stack is empty, the POPALL statement has no effect (i.e., it does not result in an exception branch).
GOSUB 1000 . 500 PRINT (0) "CUSTOMER OVER CREDIT LIMIT." . 1000 OPEN (1) "C1A",EXCP=9000 READ (1,1000) EXCP=8000 IF ARTOTAL > 0 THEN 2000 . RETURN ! 2000 FLAG1$ = "Y" IF ARTOTAL > CRLIMIT THEN POPALL AND GOTO 500 . RETURN
In this example, the main section of the program directs control to subroutine label 1000. Within that subroutine, if a certain condition is met (namely if ARTOTAL is greater than 0), program control is directed to a nested subroutine at label 2000.
Within the nested subroutine, if a certain condition is met (in this case, ARTOTAL greater than CRLIMIT), all return addresses are popped from the subroutine stack and program control is transferred directly to statement 500 in the main section.