Messages in this thread | | | Date | Wed, 6 Oct 2004 17:18:01 +0200 | From | bert hubert <> | Subject | Re: UDP recvmsg blocks after select(), 2.6 bug? |
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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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