Re: Questions about select for sockets

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

On Apr  6 20:24, Corinna Vinschen wrote:
> On Apr  6 13:37, Ken Brown wrote:
> > On 4/6/2021 12:28 PM, Corinna Vinschen wrote:
> > > On Apr  6 11:44, Ken Brown wrote:
> > > > On 4/6/2021 10:33 AM, Corinna Vinschen wrote:
> > > > > 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
> > > > 
> > > > This seems surprising to me.  Is it really the shutdown that caused it to be
> > > > ready for writing in your test, or was it ready for writing anyway (e.g.,
> > > > because the relevant buffer was empty)?
> > > 
> > > I guess so, too.  How to make sure the socket isn't ready for writing
> > > without going to great lengths?
> > 
> > I guess you could have a subprocess write to the socket in a loop, so that
> > its buffer will quickly fill up and a further write will block.
> 
> Yeah, I was trying to minimize work, but I now lazily created a blocking
> server in the same process with a non-blocking client, calling send(2)
> until it fails.
> 
> And now everything is as expected.  SHUT_RD -> ready for reading,
> SHUT_WR -> ready for writing, SHUT_RDWR -> ready for both.
> 
> I attached my STC, for completeness.  Call with an argument
> 0 (== SHUT_RD), 1 (== SHUT_WR), or 2 (== SHUT_RDWR).

I pushed a patch to handle this better.  Please have a look.


Thanks,
Corinna