erlang udp server

readme.md

running from a shell:

max [ ~/src/erlang/hello ]$ erl Erlang/OTP 18 [erts-7.2.1] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false]

Eshell V7.2.1 (abort with ^G) 1> c(hello). {ok,hello} 2> hello:start(). test ok 3>

running compiled erlang code:

erlc hello.erl

(writes hello.beam)

erl -noshell -s hello start -s init stop

"-s hello start" causes hello:start(). to be called

"-s init stop" causes init:stop(). to be called after the previous finishes

(otherwise erl will hang)

hello.erl

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

% entry point
start() ->
    {ok, Sock} = inet_udp:open(1337),
    io:format("opened UDP socket:~p~n", [Sock]),
    loop(Sock).

% loop which holds socket ref and writes OK back to clients
loop(Sock) ->
    receive
	{udp, Socket, Host, Port, Bin} ->
	    io:format("got message:~p~n", [Bin]),
	    ok = inet_udp:send(Socket, Host, Port, "OK\n"),
	    loop(Sock)
    end.

https://github.com/blackberry/Erlang-OTP/blob/master/lib/kernel/src/inet_udp.erl