IBM AS/400 manual Example of Unhandled Function Check, Operation as well, PGM1

		Using Exception Handlers
Note: The	same	exception handling events described would apply to a
call	(CALLB	operation) as well.

Example of Unhandled Function Check

The following scenario describes the events which occur when a funct occurs in a main procedure and is not handled. This scenario has th assumptions:

1. There are		two	programs,	PGM1	and	PGM2, each	containing a procedur
PRC1	and PRC2 respectively.
2. PRC1	calls	PGM2	dynamically	and	PRC2	receives	control.

3. The CALL operation code in PRC1 does not have an error indicator

4. No RPG	exception handlers have been coded	in PRC2. That is, ther
error	indicator coded and there is no *PSSR	error subroutine.

5. PRC2 has a pointer address error.

When PGM1 calls PGM2, a pointer error occurs because the basing point defined as null. Consequently, MCH1306 is generated. A function check o when PRC2 tries to percolate the exception past the control boundary depicts this scenario and the events which occur.

PASS 1

Call Stack Active Exception Handler List

Percolate MCH3601

PASS 2

Procedure PRC1

CALL PRC2

Procedure PRC2

D FLD S 5A BASED(PTR)

CEVAL PTR=NULL C EVAL FLD='ABCDE'

MCH3601 issued

RPG default Hdlr

RPG default Hdlr

Call Stack Active Exception Handler List

Percolate CPF9999

Procedure PRC1

CALL PRC2

Procedure PRC2

D FLD S 5A BASED(PTR)

CEVAL PTR=NULL C EVAL FLD='ABCDE'

CPF9999 issued

RPG default Hdlr

RPG default Hdlr

Figure 110. Scenario for Unhandled Function Check

Chapter 12. Handling Exceptions225