HP-UX SNAplus2 R7 APPC Programmer's Guide

Concepts
Synchronous and Asynchronous APPC Calls
Reset
The conversation has not started or has been terminated.
1.7.6 Half-Duplex Verbs Not Permitted in Full-Duplex Conversations
The following verbs apply only in half-duplex conversations, and are not required in full-duplex conversations. Any
of these verbs issued in a full-duplex conversation will receive an error return code.
• [MC_]CONFIRM
• [MC_]CONFIRMED
• [MC_]PREPARE_TO_RECEIVE
• [MC_]RECEIVE_AND_POST
• [MC_]REQUEST_TO_SEND
• [MC_]TEST_RTS
• [MC_]TEST_RTS_AND_POST
1.8 Sending and Receiving Expedited Data
In addition to the normal data sent using [MC_]SEND_DATA and received using receive verbs, APPC TPs may
also send and receive SNA expedited data. This data is handled separately by the SNA network, and may arrive at
the destination before normal data. A TP sends expedited data using the [MC_]SEND_EXPEDITED_DATA verb,
and receives it using the [MC_]RECEIVE_EXPEDITED_DATA verb; expedited data will never be returned on the
standard receive verbs.
Not all APPC implementations support expedited data. If the remote TP is using an APPC implementation other
than SNAplus2 that does not support expedited data, the local TP cannot send or receive it.
Because expedited data flows separately from normal data, a TP can issue [MC_]SEND_EXPEDITED_DATA or
[MC_]RECEIVE_EXPEDITED_DATA in any conversation state except Reset state. These verbs do not cause any
state change.
1.9 Synchronous and Asynchronous APPC Calls
UNIX
On HP-UX systems, SNAplus2 provides two alternative entry points to the APPC library:
• Synchronous entry point, APPC. If the application uses this entry point, SNAplus2 does not return control to
the application until verb processing has finished.
• Asynchronous entry point, APPC_Async. If the application uses this entry point, SNAplus2 returns control
to the application immediately. When verb processing has finished, SNAplus2 uses an application-supplied
callback routine to return the results of the verb processing to the application.
WINDOWS
On Windows systems, SNAplus2 provides three alternative entry points to the APPC library:
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