EXIT statement

Purpose

Transfer program execution out of a block structure.

Syntax

EXIT [FOR | FUNCTION | IF | DO | LOOP | MACRO | SELECT | SUB | TRY]

EXIT [, EXIT] [, ...] [, ITERATE]

Remarks

The EXIT statement lets you leave a structure prematurely. Using EXIT by itself will leave the most recently executed structure. For example:

FOR ix = 1 TO 10

DO UNTIL x > 10

...

EXIT ' will exit from the DO LOOP

LOOP

*EXIT* *option*	Structure exited
FOR	FOR/NEXT loop
FUNCTION	FUNCTION/END FUNCTION function
IF	IF/END IF block (see notes below)
DO or LOOP	DO/LOOP or WHILE/WEND loop
MACRO	MACRO/END MACRO block
SELECT	SELECT statement
SUB	SUB/END SUB procedure
TRY	TRY/END TRY block

If you want to exit a structure other than the one most recently executed, you must include that type of structure as part of the EXIT statement, as follows:

FOR ix = 1 TO 10

DO UNTIL x > 10

...

EXIT FOR ' will exit DO and FOR NEXT loop

LOOP

Using EXIT is preferred over using GOTO.

You can exit nested loops by using multiple EXIT statements without the loop type, and separated by commas:

EXIT, EXIT ' exit both loops

LOOP

You can also exit one loop and immediately iterate another:

FOR x = 1 TO 10

EXIT, ITERATE

LOOP

' never gets here

If you EXIT the PBMAIN or WINMAIN function, your program will stop running.

Care should be exercised when constructing exits within a nested IF/THEN block. For example:

IF x& THEN

IF y& THEN

{statements1}

EXIT IF

{statements2}

END IF

{statements3}

END IF

In the above nested block, the EXIT IF statement exits only the inner IF/THEN block (in which the EXIT statement is located), resulting in execution continuing at the {statements3} portion. That is, EXIT IF does not exit the overall IF/THEN structure.

Whilst EXIT can provide a convenient mechanism to escape a structure, subtle logic problems can arise when converting a nested single-line IF statement into an IF-block structure. For example:

IF x& = 1 THEN

IF y& = 82 THEN EXIT IF

y& = 12

END IF

…is not logically equivalent to:

IF x& = 1 THEN

IF y& = 82 THEN

EXIT IF

END IF

y& = 12

END IF

Restrictions

Before using EXIT to leave a Function, you should assign the desired function result before EXIT is executed. By default, the value returned by the function will be zero or an empty string as determined by the Function return type. For example:

FUNCTION x() AS LONG

...

IF condition THEN

FUNCTION = -1&

EXIT FUNCTION ' return -1

END IF

...

END FUNCTION