Simulate Thread.Join

[Michael D. Ober]

In the non-pooled System.Threading.Thread class, there is a Join method that
will wait until the thread is complete. How can I easily simulate this
using the thread pool. Basically, I have an application that, given it's
druthers, would generate over 300 threads, but because of resource
limitations, 10 to 15 is a realistic maximum before thread contention
becomes an issue. I know I can control the number of worker threads in the
thread pool, but I don't know how to detect that all the threads (or for
that matter, any specific thread) is complete. I need something akin to
Thread.Join.

Thanks,
Mike.

 

[UL-Tomten]

In the non-pooled System.Threading.Thread class, there is a Join method that
will wait until the thread is complete. How can I easily simulate this
using the thread pool.

Use the static System.Threading.WaitHandle.WaitAll using
AutoResetEvents passed when Queueing your UserWorkItems.

http://msdn2.microsoft.com/en-us/library/system.threading.waithandle.waitall.aspx

 

[Michael D. Ober]

Can I add to the array while it's being waited on? My problem domain
involves walking directories on a remote system and I don't know how many
threads will be created on any given run.

Mike.

 

[UL-Tomten]

Can I add to the array while it's being waited on? My problem domain

If the number of workers changes while you wait, it sounds like you
don't need a Thread.Join at all, but rather some implementation of the
consumer/producer pattern:

http://www.yoda.arachsys.com/csharp/threads/deadlocks.shtml

 

[Michael D. Ober]

What I ended up doing was creating a application global Semaphore with the
initial count and maximum count the same. Then at the beginning of each
thread I did a waitone on the semaphore. At the end of the thread
processing, I did a Release on the semaphore. This results in a lot of
threads being created (my test run created over 300 threads), but only a few
in a running state at any given time with the rest waiting on the semaphore.
The specific order the threads run was immaterial to this application - just
that they all run.

Thanks,
Mike.