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POSocket server cannot accept data after set active mode 'once'
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  1. POSocket server cannot accept data after set active mode 'once'
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    copied!<p>I'm a erlang newbie. When I read the Socket chapter from "Programming Erlang" and doing some examples according to the tutorial, there is a problem.</p> <p>In the chapter "The Hybrid Approach (Partial Blocking)", I do the following:</p> <pre><code>loop(Socket)-&gt; receive {tcp, Socket, Bin} -&gt; io:format("Server received binary = ~p~n",[Bin]), Str = binary_to_term(Bin), io:format("Server (unpacked) ~p~n",[Str]), Reply = lib_misc:string2value(Str), io:format("Server replying = ~p~n",[Reply]), gen_tcp:send(Socket, term_to_binary(Reply)), inet:setopts(Socket,[binary,{active, once}]), %Configure socket as active loop(Socket); {tcp_closed, Socket} -&gt; io:format("Server socket closed~n") end. start()-&gt; {ok,Listen} = gen_tcp:listen(2345,[binary,{packet,4}, {reuseaddr, true}, {active, once}]), {ok, Socket} = gen_tcp:accept(Listen), loop(Socket). sendData(Str)-&gt; {ok,Socket}=gen_tcp:connect("localhost",2345,[binary,{packet,4}]), ok=gen_tcp:send(Socket, term_to_binary(Str)), receive {tcp,Socket,Bin}-&gt; io:format("Client received binary = ~p~n",[Bin]), Val = binary_to_term(Bin), io:format("Client result=~p~n",[Val]) % gen_tcp:close(Socket) end. </code></pre> <p>Then I open one terminal like this: $erl</p> <blockquote> <p>server:start().</p> </blockquote> <p>and open another terminal like this: $erl</p> <blockquote> <p>client:sendData("1233").</p> </blockquote> <p>At server, it will output: Server received binary = &lt;&lt;131,107,0,3,49,50,51>> Server (unpacked) "123" Server replying = 123</p> <p>At client, it will output: Client received binary = &lt;&lt;131,97,123>> Client result=123</p> <p>But when the client sendData second time, there is not any response at server. Is there something wrong? Thank you.</p>
 

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