How do I overheat my iphone by running multiple processes in code

Question

I saw some handwarmer apps and I guess it's very easy to make something like that by running multiple processes at once. Has anyone had a go on it? If you did, can you share it with us here?

Unless the phone is jailbroke, you can't run multiple processes on the iPhone. Is this for a jail broken phone? — Brandon Bodnar, Mar 23 '10 at 17:47
@Brandon: any app can run multiple threads. Most GPS Nav apps are already "handwarmers" as is. — Kendall Helmstetter Gelner, Mar 23 '10 at 18:33
@Kendall: I know that you can run multiple threads. I was just pointing out you can't start multiple processes as a 3rd party developer without a jailbreak. — Brandon Bodnar, Mar 23 '10 at 18:47
Go to the app store and search for the 11 "hand warmer" apps on the store. Read the comments. That is what awaits you. — willc2, Apr 06 '10 at 04:47

score 1 · Accepted Answer · answered Mar 23 '10 at 18:36

Just find some endlessly repeating calculation (like something that finds the digits in Pi for example), and launch three or four threads performing them - either an NSOperationQueue with a concurrent count set to four, or just spawn off threads yourself.

The key is to make the system work in some way, you can either exercise the CPU or the GPU (or both).

score 0 · Answer 2 · answered Mar 23 '10 at 17:50

You can easily spawn several threads:

- (void) reticulateSplines {
    while (1) ;
}

- (void) spawnThreads {
    for (int i=0; i<kNumberOfThreads; i++)
        [self performSelectorInBackground:@selector(reticulateSplines)
              withObject:nil];
}

That’s not several processes and probably does not warm the machine up, though.

How do I overheat my iphone by running multiple processes in code

2 Answers2