PerformSelectorInBackground leaking on device

Question

While it seems to not pose a problem on the simulator, using performSelectorInBackground on the device causes memory leaks. Or at least that's what Instruments indicates. Looking at the code I don't have a single clue what the cause could be. I tried to strip the affected code to a bare minimum but still strangely Instruments keeps showing a leak every time this piece of code is executed.

Anything unusual going on here?

 //In viewcontrollerA:
    -(void)mainLoop
    {
     [self.viewControllerB performSelectorInBackground:@selector(calculateTotals) withObject:nil];

            //This gives the same problem
         //[NSThread detachNewThreadSelector:@selector(calculateTotals) toTarget:self.viewControllerB withObject:nil];

            //UI stuff ...

    }

    //viewControllerB:
    -(void)calculateTotals
    {
     NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

     //Heavy calculations ...


     [pool release];
    }

Edit: I'm still looking into this and it seems that the leak is caused by the fact that somewhere down the stack [NSThread start] is never followed by [NSThread exit]. So it appears like there is occasionally a thread which is kept running without ever ending it. Now my question is, is there something I could do to make end those 'hanging' threats manually?

Answer 1

Perhaps one of your threads is throwing an exception? Exceptions in threads don't get reported in the debug console, you have to catch the exception in the thread.