title: Seeking an "exit" equivalent in Swift
body: <p>I tried putting <code>exit(0)</code> in a small test (command-line) program. Xcode gave an error message stating <code>Use of unresolved identifier 'exit'</code>. This was confusing to me, since <a href="https://stackoverflow.com/questions/24055924/how-to-set-exit-code-value-for-a-command-line-utility-in-swift">this question</a> seemed to show <code>exit()</code> works. After combing through "The Swift Programming Language" I couldn't find any mention of an <code>exit</code> keyword/command. So how do you explicitly halt execution in Swift?</p>