[erlang-questions] Setting socket options on listen / accept

[Tianxiang Xiong]

OK, so the same options need to be set for listen / accept? That seems kind
of redundant--is there a reason for that? Or are these usually different
options?

On Tue, Feb 6, 2018 at 12:14 AM, Karl Velicka <karolis.velicka@REDACTED>
wrote:

> Hi,
>
> You don't have to set the options separately for accept, there's a two
> argument version that takes a proplist of socket options.
>
> When you're using gen_tcp:listen then you're setting up a server that
> receives connections, whereas `accept` is connecting to something that's
> listening to connections. You need to set the socket options separately in
> each case.
>
> Hope that helps!
>
> On 6 Feb 2018 07:55, "Tianxiang Xiong" <tianxiang.xiong@REDACTED> wrote:
>
> In Joe's Programming Erlang 2nd E
> <https://pragprog.com/book/jaerlang2/programming-erlang>, Chpt. 17, pg.
> 274, he says:
>
> After we have accepted a connection, it’s a good idea to explicitly set
>> the required socket options, like this:
>
>
> {ok, Socket} = gen_tcp:accept(Listen),
> inet:setopts(Socket, [{packet,4},binary,{nodelay,true},{active, true}]),
> loop(Socket)
>
> Until then the book's been doing:
>
> {ok, Listen} = gen_tcp:listen(2345, [binary, {packet, 4}, {reuseaddr,
> true}, {active, true}])
> {ok, Socket} = gen_tcp:accept(Listen),
> ...
> loop(Socket)
>
> Is there a reason we need to set the options after accept? Is it necessary
> to set options on listen *and* accept?
>
>
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>
>
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