ult for Xcode&#39;s Debug
configuration): if <code>condition</code> evaluates to false, stop program
execution in a debuggable state after printing <code>message</code>.</p></li><li><p>In -O builds (the default for Xcode&#39;s Release configuration):
if <code>condition</code> evaluates to false, stop program execution.</p></li><li><p>In -Ounchecked builds, <code>condition</code> is not evaluated, but the
optimizer may assume that it <em>would</em> evaluate to <code>true</code>. Failure
to satisfy that assum