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From: i91@nikhefh.UUCP (Fons Rademakers)
Newsgroups: comp.sys.apollo
Subject: How to simulate A-synchronous System Traps (AST)?
Message-ID: <372@nikhefh.UUCP>
Date: Thu, 25-Jun-87 10:30:33 EDT
Article-I.D.: nikhefh.372
Posted: Thu Jun 25 10:30:33 1987
Date-Received: Sat, 27-Jun-87 06:53:43 EDT
Reply-To: i91@nikhefh.UUCP (Fons Rademakers)
Distribution: world
Organization: Nikhef-H, Amsterdam (the Netherlands).
Lines: 35

As far as I know Apollo does not have something like the 
VAX AST (Asynchronous System Trap) facility. I would like to
know, however, how I could simulate something like this AST facility.

I ask this because I am making an application that has to react
to IPC events and to DIALOG events. I have a routine that sets and looks
at the eventcounts for both events and jumps to the respective
event input routines. The problem however is that the gpr (dialog) 
eventcount is always increased when the locator (i.e. the mouse) 
is moved, even when the mouse is outside the pad connected to the 
process. This results in a lot of task_id=0 and event_id=0 events,
which makes the cursor flicker unpleasantly (because of the quick
succession of gpr_$acquire and release calls).

It would be much nicer to be able to setup an AST routine for IPC
events. This routine would then be called, a-synchronously, whenever
an IPC event occurs.

I could simulate something like AST's by sending, before sending IPC data,
a DOMAIN/IX kill(pid, SIGUSR1) signal to the remote process which then
jumps in its SIGUSR1 fault handling routine to receive the IPC data.
The problem with this scheme, however, is that I lose the ability to
send my IPC messages between different nodes, since I don't know
how to send kill's across nodes. Also I don't know how to find the PID of
a process of which I only know its name. Are there some undocumented
proc2_$... and pm_$... routines to do this?

To be short, does somebody know how to solve this problem elegantly?

Regards, Fons Rademakers.
-- 
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