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From: Andreas.Kaiser@p0.f7014.n244.z2.Fidonet.stgt.sub.org (Andreas Kaiser)
Newsgroups: comp.os.os2.programmer
Subject: Help With Unblocking Threads
Message-ID: <669205541.1@ananke.Fidonet.stgt.sub.org>
Date: 17 Mar 91 09:09:00 GMT
Sender: FredMail@p822.f7014.n244.z2.Fidonet.stgt.sub.org
Lines: 24


In einer Message an All, vom <16 Mar 142 03:02>, schreibst Du:

 CG> I have a multi-thread application. There are 4 threads, although
 CG> only 2 are of interest here. The main thread controls network
 CG> operations, and thread 2 controls the keyboard. If the user wants
 CG> to terminate the connection, they hit Esc. When the keyboard thread
 CG> detects the Esc key stroke, it calls DosFlagProcess and ends. This
 CG> in turn unblocks the network read (EINTR) and thread 1 cleans up
 CG> and does some other processing. This all works great.

 CG> A problem arises however when the server application wants to end
 CG> the transaction. The network read ends when the connection is closed,
 CG> but how do I end the keyboard thread???

By DosExit :-). The "famous" multi-threading of OS/2 is seriously incomplete, since the only way to control threads is Suspend. That's it. No signalling, no way to kill a thread.

If you need threads which have to communicate by signals or have to kill each other, use parallel processes with shared memory.

There is another way: The MSDOS approach ;-). Forget all you learnt about efficient multitasking and do a timer-poll on every resource which does not have a timeout possibility. Not the way OS/2 was built for, but sometimes is the only way to do real-time processing, especially since device monitor calls do not have timeouts.

                Gruss, Andreas

 * Origin: kaiser@ananke.stgt.sub.org - Stuttgart (2:244/7014.0)