Memory warning and crash (ARC) - how to identify why it's happening?

Question

I\'ve started to use the ARC recently and since then I blame it for every single memory problem. :) Perhaps, you could help me better understand what I\'m doing wrong.

Answer 1

So, nothing you are doing relative to memory management (there is none!) looks improper. However, you mention using NSOperationQueue. Those UIGraphics... calls are marked as not thread safe, but others have stated they are as of iOS 4 (I cannot find a definitive answer to this, but recall that this is true.

In any case, you should not be calling these class methods from multiple threads. You could create a serial dispatch queue and feed all the work through that to insure single threaded usage.

What's missing here of course is what you do with the images after using them. Its possible you are retaining them in some way that is not obvious. Here are some tricks:

• in any of your classes that use lots of images, add a dealloc() method that just logs its name and some identifier.

• you can try to add a dealloc to UIImage to do the same.

• try to drive your app using the simplest possible setup - fewest images etc - so you can verify that in fact that the images and their owners are getting dealloc'd.

• when you want to make sure something is released, set the ivar or property to nil

I converted a 100 file project to ARC last summer and it worked perfectly out of the box. I have converted several open source projects to ARC as well with only one problem when I improperly used bridging. The technology is rock solid.