Specifying the Delivery Options for Messages

The XCF signaling service supports options that allow ordered message delivery between members and the specification of a time limit within which message delivery must complete.

Ordered message delivery means that messages are presented for input to the receiving member's message user routine in exactly the same order that they were accepted by the XCF Message Out service. Ordered message delivery is only provided between a particular pair of members; the sequencing is performed for a particular sender and receiver pair. The sender must ensure that the message-out requests are made in the desired order. The sender should wait for successful return from the XCF Message Out service before initiating the next ordered request for the same sender/receiver pair.
A timeout value is the amount of time a sender is willing to wait for its IXCMSGOX request to complete. XCF can notify the sender when the timeout value has been exceeded and the message is no longer available for processing.
The timeout value can also be used to indicate that XCF is to queue any messages that cannot be sent because of a lack of XCF resources (such as buffers or signaling paths). See Queueing Messages for Later Delivery for a description of this service.