Multiple ASTs for a Lock in a single process ?

From: JF Mezei (jfmezei.spamnot_at_istop.com)
Date: 03/08/04 

Date: Mon, 08 Mar 2004 16:05:58 -0500

Ok, I have ALL-IN-1 do LIB$FDIND_IMAGE_SYMBOL against a shareable image of
mine, then executes a routine inside that image. 99% of the time is spent
inside my routine (for instance, when waiting for calls from the web server).

ALL-IN-1 takes a lock called OA$_SHUTDOWN with a blocking AST. (see details of
that lock at bottom of this post). Its only "Flag" is "SYSTEM".

I have tested this yesterday. When the shutdown comes into effect, a user A1
process doesn't exit until the user enters the next command. So it would seem
that the blocking AST only sets a flag. There is a DCL procedure that also
runs which will do a rather blunt STOP/ID on any process still running Allin1
after 2 minutes (does a show dev/files/nosys and then searches for all
processes with a channel to a specific allin1 file).

Back to my problem: Is there a way for my routine to also be notified when the
system manager notifies processes of the A1 shutdown ? Can one take the same
lock twice in the same process ?
Or would the only way be to have my routine cancel the lock taken by All-IN-1
and reissue it with the blocking AST pointing to my own code (which would then
call the AST that had been specified by A1 after doing my own stuff) ?

My concern is that when the shutdown is done during iddle time, no commands
would be sent by my routine to ALL-In-1, so ALL-In-1 woudln't exit by itself
and thus be unceremoniously killed. What I want is to have DCL code look at
the exit status and determine is it is just a temporary shutdown or a
requested shutdwon (with temprary shutdown, the DCL could wait a couple
minutes and then try to restart the app).

Here is what SDA tells me about the lock :

Process index: 0057 Name: A1 Extended PID: 20400557
-------------------------------------------------------
Lock data:

Lock id: 0E00077C PID: 000A0057 Flags: SYSTEM
Par. id: 00000000 SUBLCKs: 0
LKB: 80C5A000 BLKAST: 000B260A
PRIORTY: 0000

Granted at CR 00000000-FFFFFFFF

Resource: 54554853 5F24414F OA$_SHUT Status:
 Length 13 0000004E 574F445F _DOWN...
 User mode 00000000 00000000 ........
 System 00000000 00000000 ........

Local copy

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