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About threading? How to know if threads finished?

Hello. I'd like to know if there's a way to know if all threads started
using the threadpool are finished.

How can I ensure that all threads finished?

--

Regards,

Diego F.

Jun 7 '07 #1
8 2643
Your own pooled threads would have to let you know somehow... perhaps
a synchronised counter? and if your threads Pulse when decrementing
you should be able to simulate a Join (to all):

private static int threadCount;
private static readonly object threadLock = new object();
private static void ThreadStarted() {
lock (threadLock) {
threadCount++;
}
}
private static void ThreadEnded() {
lock (threadLock) {
threadCount--;
if(threadCount< =0) {
Monitor.Pulse(t hreadLock);
}
}
}
private static void WaitForAll() {
lock (threadLock) {
while (threadCount 0) {
Monitor.Wait(th readLock);
}
}
}
private void ThreadMethod() {
ThreadStarted() ;
try {
// do somthing
} finally {
ThreadEnded();
}
}
Jun 7 '07 #2
or more conveniently... (note I have not either approach myself...
just thinking aloud...)
private static void ThreadMethod() {
using (new ThreadWatcher() ) {
// do something
}
}
private sealed class ThreadWatcher : IDisposable {
private bool disposed;
public ThreadWatcher() {
ThreadStarted() ;
}
void IDisposable.Dis pose() {
if (!disposed) {
ThreadEnded();
disposed = true;
}
}
// perhaps move the related methods / fields for start / end /
wait method here too...
}

Marc

"Marc Gravell" <ma**********@g mail.comwrote in message
news:uR******** ******@TK2MSFTN GP05.phx.gbl...
Your own pooled threads would have to let you know somehow...
perhaps a synchronised counter? and if your threads Pulse when
decrementing you should be able to simulate a Join (to all):

private static int threadCount;
private static readonly object threadLock = new object();
private static void ThreadStarted() {
lock (threadLock) {
threadCount++;
}
}
private static void ThreadEnded() {
lock (threadLock) {
threadCount--;
if(threadCount< =0) {
Monitor.Pulse(t hreadLock);
}
}
}
private static void WaitForAll() {
lock (threadLock) {
while (threadCount 0) {
Monitor.Wait(th readLock);
}
}
}
private void ThreadMethod() {
ThreadStarted() ;
try {
// do somthing
} finally {
ThreadEnded();
}
}

Jun 7 '07 #3
What I'm looking for is a way of blocking the main thread until all threads
in ThreadPool are finished.

Is that possible with ThreadPool object?

--

Regards,

Diego F.
"Diego F." <di********@msn .comwrote in message
news:uU******** ******@TK2MSFTN GP02.phx.gbl...
Hello. I'd like to know if there's a way to know if all threads started
using the threadpool are finished.

How can I ensure that all threads finished?

--

Regards,

Diego F.

Jun 7 '07 #4
*all* threads? Or those that you started?

Since other code could bne using the ThreadPool, I wouldn't recommend
the first and I doubt that this is available. It seems very risky,
certainly; you should only be interested in threads that you own
(pooled or otherwise). For the second, see the WaitForAll() method
that I posted; it does exactly that - just don't call it on a pool
thread!

Marc
Jun 7 '07 #5
If I understand you, you suggest not using the ThreadPool, and starting my
own threads instead. Is that rigth?

--

Regards,

Diego F.
"Marc Gravell" <ma**********@g mail.comwrote in message
news:Ok******** ******@TK2MSFTN GP05.phx.gbl...
*all* threads? Or those that you started?

Since other code could bne using the ThreadPool, I wouldn't recommend the
first and I doubt that this is available. It seems very risky, certainly;
you should only be interested in threads that you own (pooled or
otherwise). For the second, see the WaitForAll() method that I posted; it
does exactly that - just don't call it on a pool thread!

Marc

Jun 7 '07 #6
The problem with that is if I have to start many threads.

--

Regards,

Diego F.
"Diego F." <di********@msn .comwrote in message
news:%2******** ********@TK2MSF TNGP06.phx.gbl. ..
If I understand you, you suggest not using the ThreadPool, and starting my
own threads instead. Is that rigth?

--

Regards,

Diego F.
"Marc Gravell" <ma**********@g mail.comwrote in message
news:Ok******** ******@TK2MSFTN GP05.phx.gbl...
>*all* threads? Or those that you started?

Since other code could bne using the ThreadPool, I wouldn't recommend the
first and I doubt that this is available. It seems very risky, certainly;
you should only be interested in threads that you own (pooled or
otherwise). For the second, see the WaitForAll() method that I posted; it
does exactly that - just don't call it on a pool thread!

Marc


Jun 7 '07 #7
I never mentioned anything about creating threads... all I am saying
is that your worker methods (be they thread-pool or otherwise) could
notify *something* to indicate that they are complete. I have just
tested it, and it "works OK for small values of works" - there is a
glitch that you can exit too soon if the pool item hasn't started yet
(and thus the counter is 0).

Another approach is to use a dedicated pool; I believe Jon has some
template code in his box of tricks:
http://www.yoda.arachsys.com/csharp/miscutil/

(see CustomThreadPoo l)

This should allow you to track when it is empty... or allow simple
customisation

Marc
Jun 7 '07 #8
On Jun 7, 8:07 am, "Diego F." <diego_f...@msn .comwrote:
Hello. I'd like to know if there's a way to know if all threads started
using the threadpool are finished.

How can I ensure that all threads finished?

--

Regards,

Diego F.
Take a look at how to use the WaitAll WaitHandle method:
http://msdn2.microsoft.com/en-us/library/z6w25xa6.aspx
Peter

Jun 7 '07 #9

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