WAIT and NOWAIT: Specifying whether to wait for command completion

Explanation

WAIT and NOWAIT are mutually exclusive, optional parameters to specify whether you want to wait for the HSENDCMD requested function command to complete before control is returned to the user. If WAIT or NOWAIT is used, it must immediately follow HSENDCMD and precede command.

WAIT
Wait for the HSENDCMD requested function command to complete before control is returned to the user. The following DFSMShsm commands (when used with the HSENDCMD WAIT) cannot ensure that the action will have completed at the time control is returned to the requester, because the processing of the command merely sets a flag or builds a request that is subsequently processed by another task.
  • LOG
  • QUERY SPACE
  • STOP
  • SWAPLOG
When you use the WAIT parameter with a command that processes a single item (such as one data set) or a volume as a single unit (such as DUMP), an ARC1000I message is issued if the process is successful, or an ARC1001I message is issued if the process is not successful. The following is a list of these commands:
  • ABACKUP
  • ARECOVER
  • BACKDS
  • BACKVOL with DUMP parameter
  • DELETE of a migrated data set
  • MIGRATE of a data set
  • RECALL
  • RECOVER of a data set
  • RECOVER of a volume from a DFSMSdss physical full-volume copy

Other commands, when issued with the WAIT parameter, do not issue a successful termination message or set an HSENDCMD failing return code; however, they do issue explicit error messages for failing conditions.

If you press the TSO attention key when the WAIT parameter has been specified on a command request, and you confirm your intention to “attention out” of the request, an ARC1800I message is issued. This action makes your terminal available for use but does not cause DFSMShsm to discontinue processing the request. If the request is for recalling or recovering a data set, a volume mount request (ARC0612I) message can be issued.

NOWAIT
Do not want to wait for the HSENDCMD requested function command to complete before control is returned to the user. The completion message does not occur until the requested function is complete. If the NOWAIT option is being used with the ABACKUP, ARECOVER, BACKDS, BACKVOL, DELETE, MIGRATE, RECALL, or RECOVER commands, an ARC1007I message is issued after the command has been communicated to DFSMShsm. After DFSMShsm has processed the request, a completion message (ARC1000I or ARC1001I) is written, indicating respectively success or failure of the request. If the request is for recalling or recovering a data set, a volume mount request (ARC0612I) message is issued.

Defaults

The default is NOWAIT.

Usage notes:
  1. The following are HSENDCMD return codes and their meanings:
    Return code
    Meaning
    0
    With the WAIT option, communication with DFSMShsm is successful and the function is successful.

    With the NOWAIT option, communication with DFSMShsm is successful. It is not known if the function is or is not successful.

    4
    With the WAIT option, the function has encountered an error.
    8
    With the WAIT or NOWAIT option, communication with DFSMShsm has failed.
  2. The HSENDCMD command name must precede each authorized command you issue from a TSO terminal.
  3. An HSENDCMD return code of 4 indicates that a functional error occurred during processing when one of the previously identified commands was being performed. Specific errors can be determined by the ARC1001I message and the DFSMShsm messages accompanying it. However, if the command was BACKVOL CDS, then specific errors can be determined by the ARC0741I, ARC0744E, and ARC0747I messages. Return code 4 means a functional error only when one of these specifically identified commands is issued. Note that a return code of 4 will be returned from any request when DFSMShsm cannot recognize the command or all of its parameters.
  4. These HSENDCMD return codes are set in Register 15. They can be tested in a CLIST using as variables &LASTCC or &MAXCC; They can also be tested with the COND parameter within JCL when the commands are issued in the TSO batch environment.
  5. If you issue multiple HSENDCMD commands at the same time, some specifying the WAIT parameter and others the NOWAIT parameter, all of the commands with the WAIT parameter are processed first, regardless of the order in which the commands were received.
  6. The WAIT and NOWAIT parameters of the HSENDCMD command have implications for HOLD command processing that are function specific. Refer to the specific processing function for an explanation.
Parent topic: Optional parameters of the HSENDCMD command