Re: [OT] Two sockets questions

[Jano <nono@celes.unizar.es>]

Samuel Tardieu dice...

> Sure! I'll describe the process in C, I do not know whether
> GNAT.Sockets allows you to do all those steps:
> 
>   1) Create your socket
>   2) Make it non-blocking
>   3) connect() will return immediately with either 0 (success), -1
>      with errno set to EINPROGRESS or -1 with another error (real
>      error).
>   4) If the result was -1/EINPROGRESS, do a select() on the socket for
>      writing. When it tells you that you can write, write() 0 bytes. If
>      there is no error (write() returns 0), then you are
>      connected. Otherwise, you will get an error (typically
>      -1/ENOTCONN).

Great! I must try these things.

> Jano> Second: I have a connected socket which I poll periodically for
> Jano> data. When there is no more data available and the other
> Jano> endpoint has closed the socket, I continue receiving 0 byte
> Jano> available but not notification of closed socket. It's only when
> Jano> I try to read/write that a exception is raised about the
> Jano> connection reset or something. Is there a mean to be aware that
> Jano> connection has been closed (after the available data is
> Jano> exhausted, I presume)?
> 
> If you select() the socket for reading and select() tells you that
> there is data available and if read() returns 0 bytes, then this means
> that the other side has shutdown its sending part.

Mmm... The Gnat.Sockets package has a select binding... I wonder if it 
behaves that way. I will obviously test it ;-)

A idea that comes to me: If I do a read for 0 bytes, will occur the 
same? I mean, if connection is alive, nothing happens, and if it's dead, 
error...

Many thanks!

-- 
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Jano
402450.at.cepsz.unizar.es
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