Delphi: Wait for threads to finish

Question

I read this article about creating a thread pool: http://delphi.about.com/od/kbthread/a/delphi-thread-pool-example-using-asynccalls.htm

The reason I use the author's version is because of the waitAll function he made. This is working OK except for the fact that calling waitAll blocks the GUI thus losing the idea of using threads. Any hint/tip on what's needs to be changed? I emailed the author but he didn't respond.

I thought of adding Application.ProcessMessages; in the waiting loop but I don't think it's a good idea. Thanks

Answer 1

Waiting for all tasks to complete in the GUI thread is the wrong way to do it. Don't do that.

Instead arrange for each task to signal completion to the main thread. When the main thread receives the final completion signal, it can perform whatever task is needed to executed. You might make a counter of all the tasks that are to run. Each task that completes signals the main thread which decrements the count. When it reaches zero they are all done

Or create another background thread with the sole task of waiting on all the other tasks. That's fine in a background thread as it won't block the UI. When that wait completes, send a message to the UI thread.