Messages in this thread | | | Date | Wed, 6 Oct 2004 20:04:29 +0200 (CEST) | From | Joris van Rantwijk <> | Subject | Re: UDP recvmsg blocks after select(), 2.6 bug? |
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Hello,
Many thanks to you everybody else for their helpfull comments.
On Wed, 6 Oct 2004, Alan Cox wrote: > On Mer, 2004-10-06 at 15:52, Joris van Rantwijk wrote: > > My understanding of POSIX is limited, but it seems to me that a read call > > must never block after select just said that it's ok to read from the > > descriptor. So any such behaviour would be a kernel bug. > > Select indicates there may be data. That is all - it might also be an > error, it might turn out to be wrong. > > You should always combine select with nonblocking I/O
Ok, thanks. It turns out now that I (and a lot of people with me) have always been wrong about this. I will go fix the application (dnsmasq) and try to get the fix to the author.
Sorry about my wrongly blaming the kernel. I do think this issue shows hat the select(2) manual needs fixing.
For clarity, I'd like to point out that my case has nothing to do with multi-threading. Using select from multiple threads is a totally different sort of mistake.
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