Using queues

There is a special parameter for the queue API called the queue control structure, which is called TPQCTL in the API. It contains additional parameters and response information for the queue operations. Because of the heritage of the C programming language, each parameter must be paired with a flag value that indicates that the parameter is set. Otherwise, it is ignored. The most important parameters are as follows:

• corrid is a correlation identifier up to 32 characters long. TPQCORRID must be set in flags to indicate the presence of this field.
• deq_time tells when the message should be dequeued from the queue. When TPQTIME_ABS is set in flags, deq_time contains seconds since the UTC epoch. When TPQTIME_REL is set in flags, the value is the number of seconds after enqueueing the message.
• replyqueue and failurequeue are names of queues where a successful or failure response message will be stored. TPQREPLY or TPQFAILUREQ must be set in flags to indicate...