title: Getting EXC_BAD_ACCESS in iOS 4 using dispatch_once, not in iOS 5
body: <p>I'm guessing this must be new functionality as this code fail on my iOS4 device, works fine on iOS5. I need this to work on both. I haven't moved to iOS5 yet as I still need to support iOS4, so I'm at a loss as how to workaround this ?</p>
  
  <pre><code>static dispatch_once_t oncePredicate;
  dispatch_once(&amp;oncePredicate, ^{ //EXC_BAD_ACCESS
     _sharedStoreManager = [[super allocWithZone:nil] init];            
  });
  </code></pre>
  
  <p>It's from <a href="https://github.com/MugunthKumar/MKStoreKit/blob/master/MKStoreManager.m" rel="nofollow">https://github.com/MugunthKumar/MKStoreKit/blob/master/MKStoreManager.m</a></p>