 <p>A couple of useful things:</p> <ol> <li><p>If you're running your app out of Xcode, add an exception breakpoint. In the breakpoint navigator (command-6) hit the '+' at the very bottom left to add. This will pause execution on the line that throws the exception and allow you to inspect the current scope, stack, etc.</p></li> <li><p>If you're using gdb, use <code>bt</code> to print the backtrace</p></li> <li><p>If you're using lldb, use <code>thread backtrace</code> instead</p></li> </ol>