title: Is program termination of a C++ program observable behavior?
body: <p>I could have also phrased this as <em>What constitutes observable behavior?</em></p>
  
  <p>The C++ Standard talks a lot about observable behavior, but I am not really sure if program termination is part of observable behavior.</p>
  
  <p>That is, given a program such as:</p>
  
  <pre><code>int main() {
    for(;;) {}
    return 0;
  }
  </code></pre>
  
  <p>is a conforming implementation allowed to ever terminate this program?</p>