初试Erlang, 一个小例子

tcp_test.erl

 
-module(tcp_test).
-export([start/0]).

start() ->
    spawn(fun() -> start_listen() end).

start_listen() ->
    {ok, Listen} = gen_tcp:listen(1234, [{packet, 0}, {active, true}]),
    Pid = spawn(fun() -> par_connect(Listen) end),
    gen_tcp:controlling_process(Listen, Pid). 

par_connect(Listen) ->
    {ok, Socket} = gen_tcp:accept(Listen),
    Pid = spawn(fun() -> par_connect(Listen) end),
    loop(Socket).

loop(Socket) ->
    receive
        {tcp, Socket, Bin} ->
            case inet:peername(Socket) of
                {ok, {RemoteIP, _}} ->
                    io:format("Accept connection from ~p~n", [RemoteIP]);
                {error, Why} ->
                    exit(Why)
            end,
            io:format("Accept bin ~p~n", [Bin]),
            gen_tcp:send(Socket, "you say:"  ++ [Bin] ++ "\r\n"),
            loop(Socket);
        Any ->
            io:format("Server ~p~n", [Any]),
            loop(Socket)
    end.