recv() timeout problem

David Stacey drstacey@tiscali.co.uk
Fri Jul 5 12:42:00 GMT 2013


On 05/07/13 10:00, Corinna Vinschen wrote:
> 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.

Thank you for your e-mail, and for replying so quickly. Regarding the 
recv() timeouts: no problem, it's easy enough to work around. On your 
TODO list, file this one under things to do when you've finally got that 
cat.

I think that's the last of my Poco problems out of the way. I'll give it 
a clean build and test, and send an ITP either this evening or tomorrow.

Thanks once again for your help,

Dave.


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