UCBINFO DEVCOUNT

UCBINFO DEVCOUNT

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

Use the UCBINFO DEVCOUNT macro to obtain a count of the UCBs for a device class.

Syntax

The standard form of the DEVCOUNT 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.

DEVCOUNT

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

,GROUP=DEVICELASS

,DEVCLASS=ALL	Default: ALL
,DEVCLASS=CHAR
,DEVCLASS=COMM
,DEVCLASS=CTC
,DEVCLASS=DASD
,DEVCLASS=DISP
,DEVCLASS=TAPE
,DEVCLASS=UREC

,GROUP=OTHER

,DEVGROUP=PAVBASE	Default: PAVBASE
,DEVGROUP=PAVALIAS

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

,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:

DEVCOUNT

Specifies that the system is to return a count of the UCBs.

,COUNT=count addr

Specifies the address of the fullword field that is to receive the count.

,GROUP=DEVICECLASS

GROUP specifies the grouping upon which the UCB count is based.

DEVICECLASS indicates that the UCB count is based on device classes.

Specifies the device class for which the corresponding UCBs are to be counted:

ALL: Counts UCBs for all device classes
CHAR: Counts UCBs for character reader device class
COMM: Counts UCBs for communications device class
CTC: Counts UCBs for channel to channel device class
DASD: Counts UCBs for direct access device class
DISP: Counts UCBs for display device class
TAPE: Counts UCBs for tape device class
UREC: Counts UCBs for unit record device class

,GROUP=OTHER

GROUP specifies the grouping upon which the UCB count is based.

OTHER indicates that the UCB count is not based on device classes.

,DEVGROUP=PAVBASE

,DEVGROUP=PAVALIAS

Specifies the device group for which the corresponding UCBs are to be counted.

PAVBASE, counts UCBs for Parallel Access Volume (PAV) base UCBs.
PAVALIAS, counts UCBs for Parallel Access Volume (PAV) alias UCBs.

,SUBCHANNELSET=ID

,SUBCHANNELSET=ALL

,SUBCHANNELSET=ID: Indicates the UCB count is based on one subchannel set. DEFAULT: ID
,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 UCBINFO request is to be performed. DEFAULT: 0.
,SUBCHANNELSET=ALL: Indicates the UCB count is based on all subchannel sets. DEFAULT: ID

,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 DEVCOUNT 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 DEVCOUNT function completed successfully. Action: None.
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. The system could not access the caller's parameter list. Action: Check to see if your program inadvertently overlaid the parameter list generated by 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 the correct value on the SCHSET keyword.
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 return a count of all DASD devices, code:

         UCBINFO  DEVCOUNT,COUNT=CTAREA,DEVCLASS=DASD,           X
         RETCODE=INFORTCD,RSNCODE=RSNCD
         .
         .
         .

         DS  0D
CTAREA   DS  F
INFORTCD DS  F
RSNCD    DS  F