<div dir="ltr"><div>loop(Socket) -></div><div><span class="" style="white-space:pre">    </span>case gen_tcp:recv(Socket, 0) of</div><div><span class="" style="white-space:pre">            </span>{ok, Data} -></div><div><span class="" style="white-space:pre">                   </span>gen_tcp:send(Socket, string:to_upper(Data)),</div><div><span class="" style="white-space:pre">                       </span>loop(Socket);</div><div><span class="" style="white-space:pre">              </span>{error, closed} -></div><div><span class="" style="white-space:pre">                      </span>ok</div><div><span class="" style="white-space:pre"> </span>end.</div><div><br></div><div>I get an error for string:to_upper()</div><div><br></div><div>I am trying to create a simple echo server that converts text to upper case.</div><div><br></div><div>original code: <a href="http://20bits.com/article/network-programming-in-erlang/">http://20bits.com/article/network-programming-in-erlang/</a></div><div><br></div><div><br></div><div><br></div><div><br></div></div>