s implemented using
a-sync-read-watch!.  Unlike the await-getline! procedure, the watch
will continue after a line of text has been received in order to
receive further lines.  The watch will not end until end-of-file or an
exceptional condition (&rsquo;excpt) is reached.  In the event of that
happening, this procedure will end and return an end-of-file object or
#f respectively.
</p>
<p>A port can be made non-blocking with this:
</p>
<div class="example">
<pre class="example">(fcntl [port] F_SETFL (logior 