colin@la.excelan.com (Colin Goldstein) (03/16/91)
The News Manager)
Nntp-Posting-Host: la
Organization: Novell Inc., Open Systems Div., San Jose CA.
Date: Sat, 16 Mar 1991 03:02:54 GMT
Hi, I would appreciate some help with the following problem.
I have a multi-thread application. There are 4 threads, although
only 2 are of interest here. The main thread controls network
operations, and thread 2 controls the keyboard. If the user wants
to terminate the connection, they hit Esc. When the keyboard thread
detects the Esc key stroke, it calls DosFlagProcess and ends. This
in turn unblocks the network read (EINTR) and thread 1 cleans up
and does some other processing. This all works great.
A problem arises however when the server application wants to end
the transaction. The network read ends when the connection is closed,
but how do I end the keyboard thread???
Here is the code segment I'm using:
KbdThread() /* This is thread 2 */
{
KBDKEYINFO keyinfo; /* structure for keystroke info. */
USHORT rc;
rc = KbdCharIn(&keyinfo, IO_WAIT, 0);
if (rc) {
// some error;
}
.
.
.
}
I've tried using DosClose(0), which does unblock KbdCharIn() and
returns with an error (rc = 3924). This error is undocumented and
I'm not sure that the behaviour of STDIN and STDOUT will be after
I've done this. I could live with this solution if I knew that this
error will be consistant, and if this solution will work in the
future. If anyone has any ideas please share them with me.
Thanks,
Colin
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\-------------------------------------------------------------------/Andreas.Kaiser@p0.f7014.n244.z2.Fidonet.stgt.sub.org (Andreas Kaiser) (03/17/91)
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)