UCBINFO PRFXDATA

UCBINFO PRFXDATA

z/OS MVS Programming: Authorized Assembler Services Reference SET-WTO
SA23-1375-00

Use the UCBINFO PRFXDATA macro to obtain a copy of the UCB prefix extension segment.

Syntax

The standard form of the PRFXDATA option of the UCBINFO macro is written as follows:

Syntax	Description

`name`	`name`: symbol. Begin `name` in column 1.

␢	One or more blanks must precede UCBINFO.

UCBINFO

␢	One or more blanks must follow UCBINFO.

PRFXDATA

,DEVN=`devn addr`	`devn addr`: RS-type address or register (2) - (12).

,SCHSET=`schset`	`schset` RS-type address or register (2) - (12).
,SCHSET=0	Default: 0

,UCBPTR=`ucbptr addr`	`ucbptr addr`: RS-type address or register (2) - (12). Note: Specify either DEVN or UCBPTR, but not both.

,UCBPAREA=`ucbparea addr`	`ucbparea addr`: RX-type address or register (2) - (12).

,IOCTOKEN=`ioctoken addr`	`ioctoken addr`: RX-type address or register (2) - (12).

,LINKAGE=SYSTEM	Default: SYSTEM
,LINKAGE=BRANCH

,PLISTVER=IMPLIED_VERSION
,PLISTVER=MAX	Default: IMPLIED_VERSION
,PLISTVER=`plistver`	`plistver`: 2

,RETCODE=`retcode addr`	`retcode addr`: RX-type address or register (2) - (12).

,RSNCODE=`rsncode addr`	`rsncode addr`: RX-type address or register (2) - (12).

Parameters

The parameters are explained as follows:

PRFXDATA

Specifies that the system is to obtain information from the UCB prefix extension segment.

,DEVN=devn addr

Specifies the address of a halfword that contains, in binary form, the device number of the device.

,SCHSET=schset

,SCHSET=0

Specifies the name (RS-type), or address in register (2)-(12), of an optional byte input that specifies a subchannel set for which the information from the UCB prefix extension segment is to be obtained. DEFAULT: 0.

,UCBPTR=ucbptr addr

Specifies the address of a fullword that contains the address of the UCB common segment. The caller can obtain the address of the UCB common segment by a UCBPTR parameter on a UCBLOOK macro.

,UCBPAREA=ucbparea addr

Specifies the address of a 48-character storage area into which the system copies the UCB prefix extension segment. The IOSDUPI mapping macro maps the area.

,IOCTOKEN=ioctoken addr

Specifies the address of a 48-character storage area that contains the MVS I/O configuration token. The caller can obtain this token by issuing the IOCINFO macro, which is described in z/OS MVS Programming: Assembler Services Reference ABE-HSP. If the I/O configuration token that is current when UCBINFO is invoked does not match the token whose address is supplied here, the system issues a return code to the caller.

If you set the input IOCTOKEN (specified by ioctoken addr) to binary zeros, UCBINFO sets IOCTOKEN to the current I/O configuration token.

,LINKAGE=SYSTEM

,LINKAGE=BRANCH

Specifies the type of call that the system is to generate:

SYSTEM: Specifies a Program Call (PC)
BRANCH: Specifies a Branch entry

LINKAGE=BRANCH is intended for performance-sensitive programs.

,PLISTVER=IMPLIED_VERSION

,PLISTVER=MAX

,PLISTVER=plistver

Specifies the version of the macro. PLISTVER determines which parameter list the system generates. PLISTVER is an optional input parameter on all forms of the macro, including the list form. When using PLISTVER, specify it on all macro forms used for a request and with the same value on all of the macro forms. The values are:

IMPLIED_VERSION, which is the lowest version that allows all parameters specified on the request to be processed. If you omit the PLISTVER parameter, IMPLIED_VERSION is the default.
MAX, if you want the parameter list to be the largest size currently possible. This size might grow from release to release and affect the amount of storage that your program needs.
If you can tolerate the size change, IBM recommends that you always specify PLISTVER=MAX on the list form of the macro. Specifying MAX ensures that the list-form parameter list is always long enough to hold all the parameters you might specify on the execute form; in this way, MAX ensures that the parameter list does not overwrite nearby storage.
2, if you use the currently available parameters.

To code, specify in this input parameter one of the following:

IMPLIED_VERSION
MAX
A decimal value of 2

,RETCODE=retcode addr

Specifies the address of a fullword field into which the system copies the return code from GPR 15.

,RSNCODE=rsncode addr

Specifies the address of a fullword field into which the system copies the reason code from GPR 0.

Return and reason codes

When the UCBINFO PRFXDATA macro returns control to your program, GPR 15 (or retcode addr, if you coded RETCODE) contains a return code, and GPR 0 (or rsncode addr, if you coded RSNCODE) contains a reason code.

Hexadecimal Return Code	Hexadecimal Reason Code	Meaning and Action
00	None	Meaning: The PRFXDATA function completed successfully. Action: None.
04	None	Meaning: Program error. No UCB exists for the device number specified in the DEVN parameter. Action: Correct the device number and reissue the macro.
08	01	Meaning: Program error. A caller in AR mode specified an ALET that was not valid. Action: Correct the ALET and reissue the macro.
08	02	Meaning: Program error. An error occurred when the system tried to access the caller's parameter list. Action: Ensure that you have met the environmental requirements for the macro, and reissue the macro.
08	03	Meaning: Program error. The UCB address provided by the caller does not represent a valid UCB. Action: Correct the UCB address and reissue the macro.
08	05	Meaning: Program error. An error occurred when the system referenced the caller-supplied area specified in the IOCTOKEN parameter. This reason code is valid only for callers using the IOCTOKEN parameter. Action: Correct the IOCTOKEN parameter.
08	0B	Meaning: The value specified on the SCHSET keyword is not valid. Action: Enter a valid value.
0C	None	Meaning: Environmental error. The I/O configuration token supplied through the IOCTOKEN parameter is not current. This return code is valid only for callers using the IOCTOKEN parameter. Action: Obtain the current I/O configuration token by issuing an IOCINFO macro or by setting the input IOCTOKEN parameter in the UCBINFO macro to zero.
20	None	Meaning: System error. An unexpected error occurred. Action: Supply the return code to the appropriate IBM support personnel.

Example

To invoke UCBINFO to obtain a copy of the UCB prefix extension segment, code:

         UCBINFO  PRFXDATA,DEVN=DEVNUM,UCBPAREA=UAREA,            X
         RETCODE=INFORTCD
         .
         .
         .

         DS  0D
DEVNUM   DS  H
UAREA    DS  CL48
INFORTCD DS  F