Questions about select for sockets

[Corinna Vinschen]

On Apr  6 16:20, Corinna Vinschen wrote:
> On Apr  3 14:16, Ken Brown via Cygwin-developers wrote:
> > 4. Why do we set
> > 
> >   except_ready = saw_shutdown_write () || saw_shutdown_read () ?
> > 
> > I can't find any documentation that says that a shutdown should be
> > considered an exceptional condition.  On the other hand, POSIX does say,
> > "Other circumstances under which a socket may be considered to have an
> > exceptional condition pending are protocol-specific and
> > implementation-defined."  So maybe there's some Cygwin-specific reason for
> > doing this?
> 
> Nope, this is old (and wrong) cruft.  Neither Steven's book nor the
> Linux man pages, nor testing on Linux imply that ready for exception
> is used to indicate anything other than out-of-band data.  This should
> be fixed.

We may also have to change the saw_shutdown_read/saw_shutdown_write
handling.  I checked this on Linux and what happens is:

  After shutdown (fd, SHUT_RD), the socket is ready for reading and writing
  After shutdown (fd, SHUT_RDWR), the socket is ready for reading and writing
  After shutdown (fd, SHUT_WR), the socket is ready for writing only.


Corinna