o.how_it_works">How
      it works</a>
    </h4>
<p>
      Functions foo() and bar() are supposed to alternate their execution (leave
      and enter function body).
    </p>
<p>
      <span class="inlinemediaobject"><img src="../../../../../libs/coroutine/doc/images/foo_bar.png" align="middle" alt="foo_bar"></span>
    </p>
<p>
      If coroutines were called exactly like routines, the stack would grow with
      every call and would never be popped. A jump into the middle of a coroutine
      would not be