Re: [OT] Two sockets questions

[Samuel Tardieu <sam@rfc1149.net>]

>>>>> "Jano" == Jano  <nono@celes.unizar.es> writes:

Jano> Is there a way of performing a connect without blocking on it? I
Jano> suspect not... and if not in Ada, by other means?

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).

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.

  Sam
-- 
Samuel Tardieu -- sam@rfc1149.net -- http://www.rfc1149.net/sam