TS/MP Pathsend and Server Programming Manual (H06.05+, J06.03+)

for bit 14 is 1, the server can abort the dialog by replying to the message with an error value of
FEEOF (1).
When the one-transaction-per-dialog model is used (when bit 14 of the dialog flags is equal to 0),
the server must end the dialog by replying FEOK to a message before the requester can commit
the associated TMF transaction. To allow requesters to ask the server to end the dialog, you can
program your server to recognize a user-defined “end request” command.
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 these 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
or the ACS subsystem processes.
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 either FEOK (0) or FEEOF (1); these
values direct the LINKMON process or the ACS subsystem processes to release the link for re-use.
If a processor or network failure occurs, it is possible to have a dialog abort but not receive a
Pathsend dialog abort message. Therefore, to monitor all aborted dialogs, your server must also
monitor CPU down, remote CPU down, and loss of communication with network node system
Writing Context-Sensitive Servers 73