Status codes

The I/O PCB status code is set by IMS™ in response to the server GU for the TIM. A status code of bb indicates successful completion of the GU call. Because the only data explicit-mode servers receive from the message queue is the TIM, the only call issued by the server is a GU, requesting a new TIM. Thus, the only status codes an explicit-mode server should receive are bb, which indicates successful completion of the GU; and QC, which indicates that there are no more messages on the message queue for that transaction. In response to the QC status code, the server program should end normally.