Processing of MSGEXIT

The MSGEXIT module is used to customize compiler diagnostic messages and FIPS messages. The module can customize a message either by changing its severity or suppressing it.

If the MSGEXIT module assigns a severity to a FIPS message, the message is converted into a diagnostic message. (The message is shown in the summary of diagnostic messages in the listing.)

A MSGEXIT summary at the end of the compiler listing shows how many messages were changed in severity and how many messages were suppressed.

Table 1. **MSGEXIT processing**
Action by compiler	Action by exit module
Loads the exit module (`mod5`) during initialization
Calls the exit module with an OPEN operation code (op code)	Optionally processes `str5` and passes the status of the OPEN request to the compiler
Calls the exit module with a MSGSEV operation code (op code) when the compiler is about to issue a diagnostic message or FIPS message	One of the following actions: Indicates no customization of the message (by setting return code to 0) Specifies a new severity for (or suppression of) the message, and sets return code to 4 Indicates that the operation failed (by setting return code to 12)
Calls the exit module with a CLOSE op code	Optionally frees storage and passes the status of the CLOSE request to the compiler
Deletes the exit module (`mod5`) during compiler termination

MSGEXIT parameters

The compiler uses 10 parameters, passed by reference, to communicate with the exit module. The return code and user-requested severity parameters are set by the exit module for return to the compiler; the other items are passed from the compiler to the exit module.

Table 2. **MSGEXIT parameters**
Parameter number	Parameter item	Description of item
1	User-exit type	Halfword that identifies which user exit is to perform the operation. 6=MSGEXIT
2	Operation code	Halfword that indicates the type of operation: 0=OPEN 1=CLOSE 5=MSGSEV: customize message severity
3	Return code	Fullword, set by the exit module, that indicates the success of the requested operation. For op code MSGSEV: 0=Message not customized 4=Message found and customized 12=Operation failed
4	User-exit work area	Six-fullword work area provided by the compiler for use by the user-exit module. Sixth word: for use by MSGEXIT
5	Not used	(Used by the other exits)
6	Message exit data	Three-halfword area (on a halfword boundary). First halfword: the message number of the message to be customized Second halfword: for a diagnostic message, the default severity; for a FIPS message, the FIPS category as a numeric code Third halfword: the user-requested severity for the message (-1 to indicate suppression)
7	`str5`	First halfword (on a halfword boundary): the length of the string, followed by the string
8	Not used	(Used only by LIBEXIT)
9	Not used	(Used only by LIBEXIT)
10	Not used	(Used only by LIBEXIT)

Example: MSGEXIT user exit