nd a fully-general coroutine library can provide
      either symmetric or asymmetric coroutines. For convenience, Boost.Coroutine
      provides both.
    </p>
<h4>
<a name="coroutine.intro.h4"></a>
      <span class="phrase"><a name="coroutine.intro.stackfulness"></a></span><a class="link" href="intro.html#coroutine.intro.stackfulness">stackfulness</a>
    </h4>
<p>
      In contrast to a stackless coroutine a stackful coroutine can be suspended
      from within a nested stackframe. Execution resumes at 