HP-UX SNAplus2 CPI-C Programmer's Guide (June 2003)

Concepts
Confirmation Processing
Chapter 142
In the previous example, the first Received call has a status_received
of CM_CONFIRM_RECEIVED, indicating that a confirmation is required
before the partner program can continue.
Responding to a Confirmation Request
The invoked program issues the Confirmed call to confirm receipt of
data; this frees the invoking program to resume processing.
Deallocating the Conversation
Because the synchronization level of the conversation is set to
CM_CONFIRM, the Deallocate call sends a confirmation request with the
data flushed from the buffer.
For the second Receive call, status_received is
CM_CONFIRM_DEALLOC_RECEIVED, indicating that the partner program
requires a confirmation, generated by the Confirmed call, before the
conversation can be deallocated.