ACSE/Presentation and ROSE Interface Programmer's Guide

42 Chapter 3

Using ACSE/Presentation

Step 4: Release the Association

Processes must cooperate to ensure that no data is lost when the

association is released. This can be accomplished by requesting a release,

accepting the release, then terminating the association.

Requesting the Release

After Process A has completed sending user data, it sends a release

request to Process B using ap_snd() with the A_RELEASE_REQ

primitive (Figure 9).

Process B uses ap_poll() to monitor events, and calls ap_rcv() to receive

the release request.

Figure 3-9 Release Request

Conﬁrm the Release Request

Process B accepts the request and sends a positive response using the

ap_snd() call with the A_RELEASE_RSP primitive (Figure 3-10).

Communication

Endpoint A

Endpoint B

Process A

Process B

AP Environment A AP Environment B

Initiator

Responder

ap_snd()

ap_poll()

ap_rcv()

release request