Reason code

A fullword, set by the exit, to qualify the return code. Table 1 shows reason codes for each exit type, and which request they are checked after.

Table 1. User exit reason codes
Exit	Request	RSN=0	4	8	16
SOURCE	OPEN	No additional information	Input source information available		REINIT call required
SOURCE	READ	No additional information	Input source information available	Redrive requested ²
LIBRARY	OPEN	No additional information	End of member call required		REINIT call required
	FIND (macro or copy member)	No additional information	Input source information available	Redrive requested ²
	READ	No additional information	Input source information available	Redrive requested ²
LISTING TERM	OPEN	No additional information	When return code is 0, reason code 4 indicates the exit has provided a line length in the buffer length field. When return code is 4, reason code 4 indicates the exit has provided the data set information.		REINIT call required
SOURCE LIBRARY LISTING PUNCH OBJECT(z/OS® and CMS) TERM ADATA	PROCESS	No additional information	Return to exit with empty buffer	Redrive requested ²
LISTING PUNCH OBJECT(z/OS and CMS) TERM ADATA	WRITE	No additional information		Redrive requested ²
PUNCH OBJECT(z/OS and CMS)	OPEN	No additional information	Exit has provided the output data set information		REINIT call required
ADATA	OPEN	No additional information	Exit has provided the output data set information	Exit intends to discard type X'0002' and X'0090' records	REINIT call required
Notes: Multiple reason codes can be specified by OR-ing them together. When redrive is requested, the assembler issues any required error message and then recalls the exit with the same parameter list as before.