TS/MP Pathsend and Server Programming Manual (G06.24+, H06.03+)

Writing Pathway Servers
NonStop TS/MP Pathsend and Server Programming Manual–132500
4-16
Correlating Messages With a Dialog
When the one-transaction-per-dialog model is used, the transaction is automatically
aborted when the server returns an error value (FEEOF, or any other value besides
FEOK or FEContinue) in the reply. When the any-transaction-per-dialog model is used
(when bit 14 of the dialog flags is equal to 1), no automatic transaction abort occurs. In
either case, the requester should abort the transaction when it receives an error reply.
Correlating Messages With a Dialog
After a message with a “dialog begin” indication has been received, all messages
received on that open of $RECEIVE will pertain to that dialog until one of the following
occurs:
•
The server terminates the dialog.
•
A Pathsend dialog abort system message (system message -121) is received,
indicating that the dialog has been aborted. To receive Pathsend dialog abort
messages, the server must be monitoring system messages of this type. For more
information about Pathsend dialog abort messages, refer to “Detecting an Aborted
Dialog” later in this section.
•
A path error (such as CPU down or network down) occurs on the link to the
LINKMON process.
Continuing a Dialog
To indicate that the dialog should continue, the server replies to a message in the dialog
with an error value of FECONTINUE (70).
Aborting a Dialog
The server can abort a dialog by replying to any message in the dialog with an error
value of FEEOF (1).
Terminating a Dialog
After the dialog has started, either the requester or the server can abort it, but only the
server can end it. To end the dialog, the server replies to a message in the dialog with an
error value of FEOK (0).
Detecting an Aborted Dialog
When a dialog is aborted, either explicitly or by termination of the requester, the server
receives a Pathsend dialog abort system message (system message -121), if the server is
monitoring system messages of this type. Context-sensitive Pathsend servers must
ensure that Pathsend dialog abort system messages are monitored on $RECEIVE. The
Pathsend dialog abort system message is described in the Guardian Procedure Errors
and Messages Manual.
When a server receives a Pathsend dialog abort system message, the server should call
FILE_GETRECEIVEINFO_ to obtain the file number and process handle associated
with the message. The server can then use these parameters to identify the dialog. The
server should reply to the Pathsend dialog abort system message with an error value of