SNAX/APC Application Programming Manual

Verb Definitions
SNAX/APC Application Programming Manual—138786
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REQUEST-TO-SEND Verb
REQUEST-TO-SEND Verb
The REQUEST-TO-SEND verb informs the remote TP that the local TP wants to enter
Send state.
When the local TP is in Receive state and has data to send, it issues REQUEST-TO-
SEND to the remote TP. The verb completes immediately because it simply notifies the
remote TP. However, the transition to Send state does not occur until the remote TP
actually enters Receive state (by issuing a RECEIVE-AND-WAIT request or
equivalent).
The local TP detects that the state transition has occurred by issuing a RECEIVE-AND-
WAIT verb request until the WHAT-RECEIVED field contains a SEND or CONFIRM-
SEND (a value of 3 or 5). The remote TP can continue to send data for as long as
necessary before changing to Receive state.
Request Details
REQ-UOW-CODE
This field must contain the value 1007, which identifies the REQUEST-TO-SEND
verb.
Considerations
•
The local TP must be in the Receive or Confirm state.
•
REQUEST-TO-SEND results in an expedited SIGNAL request being sent to the
remote LU.
•
If a REQUEST-TO-SEND verb is processing when SNAX/APC receives a
CANCEL system message from the application program, SNAX/APC deactivates
the session and replies to the cancelled IPC. SNAX/APC frees the internal resources
after finishing the processing of the verb.
Request Format
?SECTION REQUEST-TO-SEND-REQ,TANDEM
01 REQUEST-TO-SEND-REQ.
02 RS-HEADER.
03 REQ-UOW-ID PIC X(2).
03 REQ-UOW-CODE PIC 9(4) COMP.
Reply Format
?SECTION REQUEST-TO-SEND-REP,TANDEM
01 REQUEST-TO-SEND-REP.
02 RSR-HEADER.
03 REP-UOW-ID PIC X(2).
03 REP-VERB-CODE PIC 9(4) COMP.
03 REP-RETURN-CODE PIC S9(4) COMP.
03 REP-RETURN-CODE-DETAIL PIC S9(4) COMP.