Waiting for ThreadPool

[Michael D. Ober]

If I use standard Threading.Threa d threads, I can issue a Join on the thread
variable and wait for it to complete. How can I do this on the Background
Worker Threads in a threadpool without looping. Basically, I will be
queuing an unknown number of worker threads in the pool and I need to wait
for them all to complete.

Thanks,
Mike Ober.

[Nick Hounsome]

Re: Waiting for ThreadPool


"Michael D. Ober" <obermd.@.alum. mit.edu.nospam> wrote in message
news:wbC1g.3973 $Fy2.3884@newsr ead3.news.pas.e arthlink.net...[color=blue]
> If I use standard Threading.Threa d threads, I can issue a Join on the
> thread
> variable and wait for it to complete. How can I do this on the Background
> Worker Threads in a threadpool without looping. Basically, I will be
> queuing an unknown number of worker threads in the pool and I need to wait
> for them all to complete.[/color]

Pool threads never exit or they wouldn't be in the pool. Consequently you
cannot Join with them.

See WaitHandle.Wait All

NB. It is crucial when using pool threads that you don't throw an exception
out of your delegate without signalling that it has exited (unlike Join
where you will get to know) therefore the delegate should ALWAYS be a
try...catch...f inally block.

Ideally you use some sort of shared object to store the completion state,
initialize it to "software messed up" at the top of the try block, set it to
"success" at the bottom, set it to sepcific errors in the catch and signal
completion in the finally block.

[Michael D. Ober]

Re: Waiting for ThreadPool


Thanks.

Mike.

"Nick Hounsome" <News@NickHouns ome.Me.Uk> wrote in message
news:JkG1g.2934 02$zk4.106149@f e3.news.blueyon der.co.uk...[color=blue]
>
>
> "Michael D. Ober" <obermd.@.alum. mit.edu.nospam> wrote in message
> news:wbC1g.3973 $Fy2.3884@newsr ead3.news.pas.e arthlink.net...[color=green]
> > If I use standard Threading.Threa d threads, I can issue a Join on the
> > thread
> > variable and wait for it to complete. How can I do this on the[/color][/color]
Background[color=blue][color=green]
> > Worker Threads in a threadpool without looping. Basically, I will be
> > queuing an unknown number of worker threads in the pool and I need to[/color][/color]
wait[color=blue][color=green]
> > for them all to complete.[/color]
>
> Pool threads never exit or they wouldn't be in the pool. Consequently you
> cannot Join with them.
>
> See WaitHandle.Wait All
>
> NB. It is crucial when using pool threads that you don't throw an[/color]
exception[color=blue]
> out of your delegate without signalling that it has exited (unlike Join
> where you will get to know) therefore the delegate should ALWAYS be a
> try...catch...f inally block.
>
> Ideally you use some sort of shared object to store the completion state,
> initialize it to "software messed up" at the top of the try block, set it[/color]
to[color=blue]
> "success" at the bottom, set it to sepcific errors in the catch and signal
> completion in the finally block.
>
>
>[/color]

[William Stacey [MVP]]

Re: Waiting for ThreadPool

In the delegate, increment an int before exit. The last delegate out closes
the door - or in this case, it does a Set(). You other thread is waiting on
event.WaitOne() similar to a Join. So one event should handle it.

try
{
// run delegate code.
}
finally
{
int c = Interlocked.Inc rement(ref count);
if ( c >= numToWait) // Last one out?
autoEvent.Set() ;
}

--
William Stacey [MVP]

"Michael D. Ober" <obermd.@.alum. mit.edu.nospam> wrote in message
news:wbC1g.3973 $Fy2.3884@newsr ead3.news.pas.e arthlink.net...
| If I use standard Threading.Threa d threads, I can issue a Join on the
thread
| variable and wait for it to complete. How can I do this on the Background
| Worker Threads in a threadpool without looping. Basically, I will be
| queuing an unknown number of worker threads in the pool and I need to wait
| for them all to complete.
|
| Thanks,
| Mike Ober.
|
|
|