root@dialog.UUCP (Christian Motz) (09/17/89)
For some time now I have tried to implement a kill-mechanism similar to the one used in UN*X on dear old Amy. I am using the exception mechanism provided by Exec. Everything works fine, I can send the "kill"-signal to the process, the process suspends execution, enters the exception handling routine and exits -- or gurus. It *ALWAYS* gurus if the process has been doing I/O when it was killed. But it is not really the process itself that gurus, but dos.library: it reports an AN_AsyncPkt (unexpected packet received). Up to now I have tried several things to prevent this kind of behaviour, but so far I haven't been successful. What is it I have overlooked? I would greatly appreciate any pointers on how to get rid of this problem. -- Christian Motz uucp: ...!uunet!mcvax!unido!nadia!dialog!root "Trust me, I know what I'm doing!" -- Sledge Hammer Bix: cmotz
dillon@POSTGRES.BERKELEY.EDU (Matt Dillon) (09/18/89)
:For some time now I have tried to implement a kill-mechanism similar
:to the one used in UN*X on dear old Amy. I am using the exception
:mechanism provided by Exec.
: Everything works fine, I can send the "kill"-signal to the process,
:the process suspends execution, enters the exception handling routine
:and exits -- or gurus. It *ALWAYS* gurus if the process has been
:doing I/O when it was killed. But it is not really the process itself
:that gurus, but dos.library: it reports an AN_AsyncPkt (unexpected
:packet received).
: Up to now I have tried several things to prevent this kind of
:behaviour, but so far I haven't been successful. What is it I have
:overlooked? I would greatly appreciate any pointers on how to get rid
:of this problem.
Because the current implementation of the send-wait packet function
for DOS only allows once packet to be pending for a process at a time.
When you enter the exception handler, interrupting an IO operation, and
then try to do another IO operation on top of it, *poof*.
Um, I would give up. There is no way to do it properly asynchronously.
Not only DOS, but you can't go interrupt arbitrary library calls
in the middle of their execution! Think of a graphics.library call
that gets interrupted!
-Matt