Erlang中的socket编程简单例子

Erlang 中gen_tcp 用于编写TCP程序，gen_udp用于编写UDP程序。一个简单的TCP服务器echo示例：

Start_echo_server()->
         {ok,Listen}= gen_tcp:listen(1234,[binary,{packet,4},{reuseaddr,true},{active,true}]),
         {ok,socket}=get_tcp:accept(Listen),
         gen_tcp:close(Listen),
         loop(Socket).
 
loop(Socket) ->
         receive
                  {tcp,Socket,Bin} ->
                            io:format(“serverreceived binary = ~p~n”,[Bin])
                            Str= binary_to_term(Bin),
                            io:format(“server  (unpacked) ~p~n”,[Str]),
                            Reply= lib_misc:string2value(Str),
                            io:format(“serverreplying = ~p~n”,[Reply]),
                            gen_tcp:send(Socket,term_to_binary(Reply)),
                            loop(Socket);
                   {tcp_closed,Socket} ->
                            Io:format(“ServerSocket closed ~n”)
         end.

Tcp 的echo客户端示例：

echo_client_eval(Str) ->
         {Ok,Socket} = gen_tcp:connect(“localhost”,2345,[binary,{packet,4}]),
         ok= gen_tcp:send(Socket, term_to_binary(Str)),
         receive
                   {tcp,Socket,Bin}->