IWMSSEM – WLM Server Select Secondary Service

The IWMSSEM service selects the next secondary work request from the queue associated with the caller's server task.

If there are no queued secondary work requests waiting for selection the calling task will be suspended, pending arrival of work to do. The caller cannot rely upon asynchronous exits receiving control while the task is suspended.

Secondary work requests are considered to be extensions of an original work request selected using IWMSSEL. The caller must invoke WLM services in the following sequence:

• The caller invokes the IWMSSEL macro to select an initial work request. IWMSSEL returns a token identifying the server task. The caller is responsible for passing the server token to the queueing manager so that it can insert secondary work requests.
• The caller invokes the IWMSTBGN macro to establish an environment for processing the work request selected using IWMSSEL. This environment also covers all secondary work requests.
• The caller invokes the IWMSSEM macro to select each secondary work request. The queueing manager is responsible for indicating the last secondary work request so that the server task knows when not to try to select another one.
• After the last secondary work request has been processed, the caller invokes the IWMSTEND macro to remove the environment created by IWMSTBGN.
• The caller invokes IWMSSEL to select a new primary work request, and repeats the above flow.

In the above flow, IWMSSEL, IWMSTBGN, IWMSSEM, and IWMSTEND must be invoked from the same task.