title: How to read objective-c stack traces
body: <p>i have the following stack trace:</p>
  
  <pre><code>0 MyApp 0x000833a3 +[TFCrashHandler backtrace] + 26
  1 MyApp 0x000836bd TFSignalHandler + 28
  2 libsystem_c.dylib 0x33eac727 _sigtramp + 34
  3 ??? 0x00000002 0x0 + 2
  4 MyApp 0x000803f1 msgpack_unpack_next + 112
  5 MyApp 0x0007faeb +[MessagePackParser parseData:] + 74
  6 MyApp 0x0007f84b -[NSData(NSData_MessagePack) messagePackParse] + 26
  7 MyApp 0x000254c3 +[Http get:params:cacheMins:msgPack:complete:] + 146
  ...
  </code></pre>
  
  <p>And i'm wondering how to read it:</p>
  
  <ul>
  <li>I assume i go from the bottom up, eg line 7 called line 6 called line 5, etc.</li>
  <li>What does the '+ 112' on line 4 mean? Is that a line number in the code file where it crashed?</li>
  <li>What does the '???' on line 3 mean?</li>
  </ul>
  
  <p>Thanks a lot</p>