Multithreaded App Stops Working

[grip003]

I have written a backup utility that simply copies certain files from one location to another on my computer. I used multithreading to handle the file copying so that I could let it run in the background while I am still working on things. The problem I am running into is that for some reason the application seems to just stop randomly some amount of time into the file copy. I also wrote a version of this software to automatically burn CD backups, and the same thing is happening. I decided to try one of my other multithreaded apps, and it also stopped in the middle of progress. These problems started occurring when I moved to a new dual-core machine. The programs seem to work fine on a single core/single processor machine. Can anyone tell me what might be wrong? Am I just not programming the multithreading correctly?

[PlausiblyDamp]

Without seeing any code it is pretty difficult to pinpoint the problem. Be aware that writing correct multi-threaded code is not a trivial task as you often need to co-ordinate the multiple threads to prevent deadlocks and race conditions occuring.

 

Any multi-cpu machine is more likely to reveal any potential issues as it is then actually running multiple threads concurrently.

[grip003]

The only resource being shared by the threads is the GUI, basically just a progress bar and a label being updated. Do you think that might be the cause of the problem?

[Wile]

If you are directly using the GUI from the separate threads, yes that can cause a lookup. GUI related stuff should be done on the thread that created the GUI components.

That sounds harder than it is, you can use <control>.InvokeRequired to see if you are on the correct thread, and <control>.Invoke to send the command to the GUI thread if you are not. Search this forum for InvokeRequired, you'll find several examples like this: http://www.xtremedotnettalk.com/showthread.php?t=86818&highlight=InvokeRequired

[grip003]

Thanks Wile, I will start looking through my code and try using the InvokeRequired stuff. I'll repost in a little while to let you know how things worked.