Asynchronous processing with DFSMShsm

Asynchronous processing of the ARCHRCAL and ARCHBACK macros is provided by the ASYNC parameter. This parameter is to be used in conjunction with a no-wait or wait request:

no-wait: Sends a request to DFSMShsm and returns control to the user as soon as the request is queued. The user is not notified of the request processing other than a completion message, if the user is logged onto TSO at the time the request ends.
wait: Sends a request to DFSMShsm and does not receive control back until the request has completed. In the return notification, a return code and reason code indicate whether the processing was successful.

The ASYNC=YES parameter allows you, as a program submitter, a way to send requests to DFSMShsm and immediately receive control back so that you can do other things while DFSMShsm is processing your request. DFSMShsm notifies you when the request is complete and returns a return code and reason code.

Before ASYNC=YES will successfully run in your requesting user program, you, as a program submitter, must perform the following tasks:

Ensure that the requesting user program is an authorized program because protected CSA storage is used to communicate the request.
Specify the ASYNC=YES option and the WAIT=YES option when you code the requested user macro.
Save the ECB address that is returned in register 1 and do not free this area until the ECB is posted. When the request is queued in CSA, control is returned to the requester. Register 1 contains the address of an ECB that is posted when the request is finished. For certain errors during an asynchronous request, register 1 contains zero indicating that an ECB is not passed. Check the return and reason codes under these conditions.
After the ECB has been posted, issue the ARCFMWE user macro to free the CSA storage used in this method by specifying the saved ECB address. Upon return from the ARCFMWE macro, the return code is in register 15 and a reason code is in register 0.