title: Which iOS classes that don't support zeroing weak references?
body: <p>Is there a list of classes in iOS that can't be referred with a <code>__weak</code> pointer when using automatic reference counting (ARC)?</p>
  <p>Apple's <a href="https://developer.apple.com/library/ios/#releasenotes/ObjectiveC/RN-TransitioningToARC/_index.html" rel="nofollow noreferrer">Transitioning to ARC Release Notes</a> only lists Mac classes so far:</p>
  <blockquote>
  <p><strong>Which classes don’t support zeroing-weak references?</strong></p>
  <p>You cannot currently create zeroing-weak references to instances of the following classes:</p>
  <p><code>NSATSTypesetter</code>, <code>NSColorSpace</code>, <code>NSFont</code>, <code>NSFontManager</code>, <code>NSFontPanel</code>, <code>NSImage</code>, <code>NSMenuView</code>, <code>NSParagraphStyle</code>, <code>NSSimpleHorizontalTypesetter</code>, <code>NSTableCellView</code>, <code>NSTextView</code>, <code>NSViewController</code>, <code>NSWindow</code>, and <code>NSWindowController</code>. In addition, in OS X no classes in the AV Foundation framework support weak references.</p>
  </blockquote>
  <p>Is there a similar list for UIKit classes or even iOS-specific classes in general?</p>
  <p>Thanks.</p>