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<div><a href="index.html" title="">Macaulay2Doc</a> > <a href="___The_sp__Macaulay2_splanguage.html" title="">The Macaulay2 language</a> > <a href="_using_spsockets.html" title="">using sockets</a></div>
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<div><h1>using sockets</h1>
<div><p>It's easy to use sockets as though they were files. Simply replace the file name by a string of the form <tt>$host:service</tt> where <tt>host</tt> is the name of IP number of host to contact, and <tt>service</tt> is the port number or name to use. If <tt>service</tt> is omitted, then port 2500 is used. If <tt>host</tt> is omitted, then an incoming connection will be listened for.</p>
<p>The following code will illustrate two-way communication using sockets similar to the interaction used by web servers, and you may try it out on your machine, unless a firewall prevents it.</p>
<pre>if (pid = fork()) == 0 then (
try "$:7500" << "hi there" << close;
exit 0;
)
sleep 2
get "$localhost:7500"
wait pid</pre>
<p>The code uses <a href="_fork.html" title="fork the process">fork</a> to create a separate process that will listen for a connection on port 7500 and then send us a message. The <a href="_sleep.html" title="sleep for a while">sleep</a> command pauses for a while to make sure the child process has had time to start listening. Then we use an ordinary input command, namely <a href="_get.html" title="get the contents of a file">get</a>, to obtain the message. Finally, we <a href="_wait.html" title="wait for child process">wait</a> for the child process to finish, as we should.</p>
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<div class="single"><h2>See also</h2>
<ul><li><span><a href="_open__In__Out.html" title="open an input output file">openInOut</a> -- open an input output file</span></li>
<li><span><a href="_open__Listener_lp__String_rp.html" title="open a port for listening">openListener</a> -- open a port for listening</span></li>
<li><span><a href="_get__W__W__W.html" title="get a web page">getWWW</a> -- get a web page</span></li>
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