recv() timeout problem

Corinna Vinschen corinna-cygwin@cygwin.com
Fri Jul 5 09:00:00 GMT 2013


On Jul  4 19:34, David Stacey wrote:
> Please find attached a short programme that demonstrates a problem
> I'm having with recv() timeouts. Under Fedora 19 x64, the test
> programme times out after three seconds (which is the desired
> behaviour). However, when run from Cygwin, the call to recv() never
> exits.
> 
> I am using the latest snapshot (2013-07-03) in 32-bit Cygwin. OS is
> Windows 7 Ultimate x64 SP1.
> 
> Many thanks in advance for your help,

Unfortunately that won't work at the moment.

The underlying implementation of recv is nonblocking.  A blocking
Windows recv call is noninterruptible, unfortunately (at least up to
Windows 2003), so this was necessary to handle signals or
thread-cancellation.

Due to its nonblocking nature under the hood, this doesn't support
SO_RCVTIMEO and SO_SNDTIMEO and, surprisingly, we never had a complaint
about that, despite its age.

I can't promise a quick solution, but I put implementing handling of
SO_RCVTIMEO and SO_SNDTIMEO in recv/send on my TODO list.  Of course,
patches are welcome, too.

For the time being, I suggest to use select or poll with timeout
instead.


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

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