[erlang-questions] gen_tcp:recv/3 timeout

[Ahmed Omar]

AFAIK, data doesn't get lost except if the socket is closed from the other
side.

On Fri, Dec 30, 2011 at 6:32 PM, Roberto Ostinelli <roberto@REDACTED>wrote:

> thank you klaar,
>
> though there's something I don't like in the proposed solution: what if
> you receive more than the intended original N bytes? there's the (un)famous
> undocumented option gen_tcp:unrecv but i'd rather not use it, plus there
> isn't an SSL equivalent for it.
>
> storing the additional received bytes for later usage seems cumbersome,
> and sometimes even unfeasible when considering that I'm often switching the
> packet type and the active options of inet.
>
> i was thinking to wrap the gen_tcp:recv/3 function around something that
> re-calls it if it timeouts, but unfortunately when it does the returned
> error {error, timeout} does *not* contain the bytes received up to that
> point, which then get lost.
>
> ..anyone?
>
>
> On Tue, Dec 27, 2011 at 7:52 AM, Magnus Klaar <magnus.klaar@REDACTED>wrote:
>
>> Hi!
>>
>> gen_tcp:recv(..., N, M) returns {error, timeout} if N bytes has not been
>> received after M milliseconds. If less bytes are available the call will
>> _not_ succeed. If you are receiving data at a slow rate specifying 0 as the
>> length is preferrable because the call will return whatever data is
>> available at the time. If there is no data available it will wait and
>> timeout if no data has been received after M milliseconds. If you don't
>> want to timeout at all when doing this, specify infinity as the timout
>> value.
>>
>> MVH Magnus
>>
>> On Tue, Dec 27, 2011 at 2:10 AM, Roberto Ostinelli <roberto@REDACTED>wrote:
>>
>>> dear list,
>>>
>>> when calling gen_tcp:recv/3 by specifying a length and a timeout, when
>>> will {error, timeout} be a response? Is it:
>>>
>>> 1. when no bytes are received for a period longer than the specified
>>> Timeout
>>> 2. when the number of bytes specified in Length is not received within
>>> Timeout
>>>
>>> if 2, what is the best solution to actually *not* have a recv/3 timeout
>>> while receiving bytes at a very low pace (for instance on very slow
>>> connections)?
>>>
>>> thank you,
>>>
>>> r.
>>>
>>
>
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-- 
Best Regards,
- Ahmed Omar
http://nl.linkedin.com/in/adiaa
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