[erlang-questions] How to solve the blocking accept call in a tcp_listener process ?

Claes Wikstrom <>
Tue May 19 23:30:40 CEST 2009


James Hague wrote:
>> Many examples uses the async_accept primitive from the module prim_inet.
>> This primitive is not documented (low level) and might change or dissapear.
>> Do you know examples which don't use it but use a "clean" solution for the blocking accept call ?
>> Or could you show an elegant solution in this forum ?
> 
> You could always put the blocking call into it's own process.  When a
> connection occurs, change the port's owner and send the port in a
> message.  (And open the port in passive mode to make sure messages
> aren't received before switching the owner.)

The way I've always done it is to spawn the acceptor as:

L = listen(...),
listen_loop(L).


listen_loop(L) ->
    Top = self(),
    spawn(fun() ->
            Sock = accept(L),
            Top ! one_more,
            handle_sock(Sock)
           end),
     receive
        one_more ->
           listen_loop(L)
     end.


/klacke



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