VTAM CANCEL command

The VTAM® CANCEL command is used by IMS, and should be used by the SLU P system to terminate a chained message in progress that has not completed.

IMS sends the CANCEL command to a workstation in these situations:
  • The IMS master terminal operator issues the IMS /DEQUEUE command and IMS has not yet sent the last-in-chain transmission of a message.
  • IMS receives an exception DR1 or DR2 to a transmission of a message and has not yet sent the last-in-chain transmission.
The controller or controller application program should use the CANCEL command in these situations:
  • When an exception DR1 or DR2 is received from IMS prior to sending the last-in-chain transmission of a message.
  • When multi-RU chained input to IMS must be canceled prior to sending the last-in-chain transmission of a message. In this case, if the message to be canceled contains only the begin-bracket indicator, the VTAM CANCEL command can include the end-bracket indicator, the change-direction indicator, or no additional indicators.