[C#] Debug mode works, Start without debugging fails

[ProChefChad]

I have an app which works great (and as expected) when I start and run it in debug mode in VS 2008 Pro. However, when I try to "Start without debugging", the app is a bust. Here's what happens:

1. I start the program
   
2. I start the main part of my program by pushing a button
   
3. The operations seem to work fine for a second, but then they don't stop when expected.
   
4. Instead, the app starts using nearly 100% of the CPU and when I close it ("X" button) it still keeps running. I have to kill it through the Task Manager.
   

I'm not sure how to debug this, since (ahhh!) I'm running it without debugging!

Does anyone know how to debug this or has anyone faced similar circumstances? I've looked online and have found next to nothing.

[night_stalker_z]

Maybe missing some files in the release folder?

[ProChefChad]

I checked and the folder contents of Debug and Release are the same. Thanks for the idea though :-) Some of the file sizes are different, but I suspect that is because the release versions don't have any of the debugging code.

[night_stalker_z]

Conditional defines?

[ProChefChad]

No, but not a bad idea either. Other ideas?

[night_stalker_z]

Is it multi threaded?

[ProChefChad]

yes, I have the main UI thread which starts an instance of a class that uses many threads to do the operations. Can you explain how this could cause the problems?

[night_stalker_z]

The VS debugger might be interfering. Do you have breakpoints?

[ProChefChad]

not any that were being hit. In fact, I deleted all breakpoints (through VS menu) and I'm still having the same problem. Any other ideas? Why would the app use 100% CPU?

[night_stalker_z]

Try running the exe from the debug folder normally and see if it takes 100% CPU.

[ProChefChad]

Yes, it does take 100% CPU from the debug folder. This is actually how I originally saw the problem, because I didn't want to load VS to run the program, so I tried running the exe from the debug folder and noticed the problem. Does this information suggest a certain problem?

[night_stalker_z]

Try doing a clean and then a build.

[ProChefChad]

Sadly, I've done this many times too.

[night_stalker_z]

Do you have some sort of Thread.Sleep(1) in the thread loop? You might need one to stop 100% cpu.

[ProChefChad]

I have this in one of the threads:

		private void ....
		{
				.....
				WaitFor(4);
				.....
		}

		private void WaitFor(double seconds)
		{
			DateTime t = DateTime.Now.AddSeconds(seconds);
			while (DateTime.Now < t)
			{
				Application.DoEvents();
			}
		}

I know this isn't great design, but needless to say events don't easily work in this situation so I'm stuck with this for now. Could this be causing the 100% CPU usage or cause the app to hang (for more than 4 seconds) and not work?

Thanks for your continued help :-)

[night_stalker_z]

Change to

		private void ....
		{
				.....
				Thread.Sleep(1);
				.....
		}

I assume this method is your thread loop.

[ProChefChad]

Actually, it's not my thread loop. It's in one of the threads that is running. Can you explain why I should use Sleep() instead of using "busy waiting + Application.DoEvents()"? I'm not quite sure what you're getting at.

I tried your suggestion and it breaks my application as I need the program running and "doing events", but I still need to wait for some amount of time. If I can avoid it, I don't want to have to wire up events as it will mean re-writing a good amount of my code. Any more ideas :-)

[night_stalker_z]

		private void ....
		{
				.....
				WaitFor(4);
				.....
		}

		private void WaitFor(double seconds)
		{
			DateTime t = DateTime.Now.AddSeconds(seconds);
			while (DateTime.Now < t)
			{
				Application.DoEvents();
				Thread.Sleep(1);
			}
		}

Try this way. It should do events and not waste 100% CPU.

[Eric Veteran]

Application.DoEvents() doesn't wait if there's nothing the Application engine needs to do. Put the Thread.Sleep() in and you should be good. It sounds like your background thread is eating up all the time. (I usually use Thread.Sleep(500) but I guess 1 should work ok.)

You can also use a System.Timer to call a delegate after the elapsed time.

[ProChefChad]

Thanks everyone. I think I'll just suck it up and go down the events route as it seems to be the most correct option at this time.