low.  Methods 
<a href=udp.html#receive><tt>receive</tt></a>  and 
<a href=udp.html#receivefrom><tt>receivefrom</tt></a>
can be used to retrieve datagrams, the latter returning the IP and port of
the  sender  as  extra  return  values (thus being  slightly  less
efficient). 
</p>

<p>
When  communication  is performed  repeatedly  with  a single  peer,  an
application  should call  the 
<a href=udp.html#setpeername><tt>setpeername</tt></a> method to specify a
permanent partner.  Methods 
<a href=udp.html#se