GDSX Manual

Extended General Device Support (GDSX) Manual–134303
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9
User Exit Descriptions
User exits are the USCODE procedures that are called by TSCODE to allow you to
customize a GDSX process. All GDSX applications need a DEVICE^HANDLER
procedure to provide the application-specific logic. You include stubs, such as those
provided in the USKEL file of the installed subvolume, for all user exits that are not
customized. To prepare a source file with all the user exits, you may modify the
USKELEX, USKELEXC, or USAMPLE example files, or write your code starting with
USKELC.
User Exit Routines
Following is a list of the supported exit routines. After the list there is an alphabetically
ordered reference section containing a description of each user exit.
TSCODE calls user exits in the following order at primary process startup time:
1. USER^INIT^CONFIG^PARAMS
2. PROCESS^ASSIGNS (called only if an ASSIGN command is entered at the TACL
prompt)
3. PROCESS^USER^PARAMS (called only if a USERPARAM command is entered at
the TACL prompt)
4. USER^VERSION
5. USER^INITIALIZE
If GDSX is run as a process pair, the backup process for TSCODE calls the same five
user exits in the same order. In the primary process TSCODE checkpoints data to the
backup and calls USER^BACKUP. Finally, if at some later time the primary process
dies, the new primary, which was formerly the backupprocess, calls
USER^TAKEOVER, followed by USER^BACKUP.
DEVICE^HANDLER
This procedure is typically used to modify the communication of each thread between a
requester and another file (often a terminal). Running copies of DEVICE^HANDLER
code are called DEVICE^HANDLER tasks.
DEVICE^HANDLER USER^INITIALIZE
LINE^HANDLER USER^INIT^CONFIG^PARAMS
PROCESS^ASSIGNS USER^REPLIES
PROCESS^USER^PARAMS USER^START
USER^ATTRIBUTES USER^STOP
USER^BACKUP USER^TAKEOVER
USER^COMMANDS USER^VERSION