发布于 2016-03-05 05:55:36 | 141 次阅读 | 评论: 0 | 来源: 网友投递
Erlang 编程语言
Erlang是一个结构化,动态类型编程语言,内建并行计算支持。最初是由爱立信专门为通信应用设计的,比如控制交换机或者变换协议等,因此非常适 合于构建分布式,实时软并行计算系统。
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.
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}->
Io:format(“Clientreceived binary = ~p~n”,[Bin]),
Val=binary_to_term(Bin),
io:format(“Clientresult = ~p~n”,[Val]),
gen_tcp:close(Socket)
end.
udp_demo_server(Port) ->
{ok,Socket}= gen_udp:open(Open,[Binary]),
loop(Socket).
Loop(Socket)->
receive
{udp,Socket,Host,Port,Bin}->
BinReply= …,
gen_udp:send(Socket,Host,Port,BinReply),
loop(Socket)
End.
udp_demo_client(Request) ->
{ok,Socket}= gen_udp:open(0,[Binary]),
ok= gen_udp:send(Socket,”localhost”,1234,Request),
Value= receive
{udp,Socket,_,_,Bin}-> {ok,Bin}
after2000 -> error
end,
gen_udp:close(Socket),
Value