Re: UDP recvmsg blocks after select(), 2.6 bug?

[bert hubert]

On Wed, Oct 06, 2004 at 04:52:27PM +0200, Joris van Rantwijk wrote:
> Hello,
> 
> I have a problem where the sequence of events is as follows:
>  - application does select() on a UDP socket descriptor
>  - select returns success with descriptor ready for reading
>  - application does recvfrom() on this descriptor and this recvfrom()
>    blocks forever

This can happen, and is fully to be expected. For a host of reasons the
packet might not in fact appear. Whenever using select for non-blocking IO
always set your sockets to non-blocking as well.

One of the legitimate reasons is the reception of packets which, on copying,
turn out to have a bad checksum.

Stevens has a section on this, recommended reading.

-- 
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