Return codes and error processing

Return codes, set in the panel user exit routine, recognized by ISPF are:

0: Successful operation.
8: Exit-defined failure. ISPF sets the .MSG control variable and displays or redisplays the panel with the message.
20 (or code unrecognized by ISPF): Severe error in the exit routine.

For an exit routine return code of 8, ISPF sets the .MSG control variable by using this search order:

If the value in the Message ID parameter is not blank on return to ISPF, that value is used for setting the .MSG control variable.
If the value in the Message ID parameter is blank on return, the value (if any) specified for the MSG= keyword on the PANEXIT statement is used for setting the .MSG control variable.
If neither the Message ID parameter nor the MSG= keyword has been given a value, the default ISPF exit error message is used for setting the .MSG control variable.

The panel section in which the .MSG control variable is set affects the message display as follows:

)INIT or )REINIT section: the message is displayed on the panel.
)PROC section: the panel, including the message to be displayed, is redisplayed.

If the return code from the exit routine is either 20 or not one of the recognized codes, the display service terminates with a severe error condition. ISPF sets the ZERRMSG system variable by using this search order:

If the value in the Message ID parameter is not blank on return to ISPF, it is used for setting the ZERRMSG system variable. This allows the exit routine to define the message to be used in case of a severe error.
If the value in the Message ID parameter is blank on return, the value (if any) specified for the MSG= keyword on the PANEXIT statement is used for setting the ZERRMSG system variable.
If neither the Message ID parameter nor the MSG= keyword has been given a value, the default ISPF exit error message is used for setting ZERRMSG.

If CONTROL ERRORS CANCEL is in effect, ISPF displays on the severe error panel the message indicated by the value of ZERRMSG.