IECIEPRM Parameter List

The parameters passed to a Version 3 or Version 4 installation exit during label processing vary slightly among different types of exits. These differences, are noted in the "Description" column in Table 1. The parameter list is passed to the exit as an address in general purpose register 1; it is 32 bytes in length and is mapped by macro IECIEPRM beginning at DSECT IECIEPRM. Parameter fields not available to a particular exit are set to zero. The only fields allowed to be altered by an exit are the return code (IECIEXRC) and the user area (IECIEUSR); changing any other field has an unpredictable effect on system processing. A flag in the parameter list indicates which type of exit was entered.

Table 1. ISO/ANSI Version 3 or Version 4 Exit Parameter List. All fields apply to all four exits unless otherwise stated in description.
Offset	Length or Bit Pattern	Name	Description
00 (X'00')	4	IECIEID	Parameter list identifier (APRM)
04 (X'04')	4	IECIESIZ	Length of IECIEPRM
08 (X'08')	4		Reserved
12 (X'12')	1	IECIEFL1	Exit flags
EXACTLY ONE OF THE FOLLOWING FOUR BITS IS ON FOR EACH CALL
	1... ....	IECIEVAL	Entry is Validity Check
	.1.. ....	IECIEVAE	Entry is Volume Access
	..1. ...	IECIEFAE	Entry is File Access
	...1 ....	IECIEVSP	Entry is Validation Suppression
	.... 1...	IECIEWRT	Label will be written (WRITE)
	.... .1..	IECIEEOV	EOV in process
13 (X'13')	1	IECIEERR	Validation error type (valid only for label validation exit)
	1... ....	IECIEVRS	Version coexistence conflict¹
	.1.. ....	IECIEUNK	Unsupported or unknown value
	..1. ....	IECIEADJ	Invalid field alignment
	...1 ....	IECIESEQ	Label sequence error
	.... 1...	IECIEDUP	Duplicate file name
	.... .1..	IECIECHR	Invalid character type
	.... ..1.	IECIEXPR	Invalid expiration date
	.... ...1	IECIESYM	Symmetry conflict²
14 (X'14')	1	IECIEPOS	Starting character position in label examined³ (Valid only for label validation exit)
15 (X'15')	1	IECIEXRC	Return code from exit processing. Set by exit.
	1... ....	IECIESUP	Suppress label validation⁵
	.000 0000	IECIERC0	Accept volume
	.000 0100	IECIERC4	Reject volume (ignored for VSP Exit)
16 (X'16')	1	IECIEJAC	User-requested file accessibility code.
17 (X'17')	2		Reserved
19 (X'19')	1	IECIEDCB	Copy of open parmlist options (4 low order bits)
	.... ..1.	IECIEOUT	Bit on for OUTPUT, OUTIN
	X'0E'	IECIEIN	These are bits off for INPUT, RDBACK
20 (X'20')	4	IECIELBL	Address of label being processed⁷
24 (X'24')	4	IECIEUCB	Address of UCB for volume will be a 24 bit actual or captured address⁸
28 (X'28')	4	IECIEUSR	User area. Set to zero by the system before the first call. Set by exit for use on later calls.
32 (X'32')	0	IECIEND	End of exit parameter list

Notes:

"Version" error is set for the open, close, EOV message routine for internal use, and the volume is unconditionally rejected.
A symmetry conflict results from a condition that produces non-matching or asymmetrical labels framing a file, and/or inconsistent file structure.
The first character position is offset 0, the second position is offset 1, and so forth.
A return code of 4 is set by the IBM-supplied exits. This causes a volume to be rejected. The exception is the validation suppression exit, which always sets a return code of zero in the IBM-supplied exits (although the system always unconditionally accepts a volume after execution of the validation suppression exit). IECIEXRC is ignored by open or EOV when control returns from RACF.
IECIESUP is recognized any time the volume access exit returns to the system, when RACF returns to the system after it was passed the parameter list, or when the validation suppression exit returns to the system.
The file accessibility code in IECIEJAC is only valid when Write Mode (IECIEWRT) was set on by the caller of the file access exit. This code comes from ACCODE (A-Z) or LABEL (password, 1 or 3) parameters from the user job step (blank, if none). If bit IECIEWRT is set and the value in IECIEJAC is valid as a file accessibility code, then IECIEJAC will be written in the file label when the exit returns.
For volume access exit and file access exit, the label area contains the accessibility code from tape. When the label area is not available to the exit, IECIELBL is zero. Binary zeros indicate data in the label that is not available to an exit. The volume accessibility code is always available in the UCB tape class extension at UCBCXACC (for ISO/ANSI) when an ISO/ANSI volume has been opened and not removed.
The UCB tape class extension for ISO/ANSI volumes contain the VOL1 label standard version number, the VOL1 owner identification, and the VOL1 accessibility code. The extension can be addressed by the following sequence:
```
LR    R1,xxx                 GET UCB ADDRESS
IOSCMXR ,                    GET COMMON EXTENSION ADDRESS
USING UCBCMEXT,R1
L     Rx,UCBCLEXT            GET CLASS EXTENSION ADDRESS
DROP  R1
USING IECUCBCX,Rx            IECUCBCX MAPPING
```
Note that the UCB tape class extension might reside above the 16 MB line.

You can use the base UCB to access the serial number for the mounted volume (in UCBVOLI).