non-blocking IO EAGAIN on write

[Kushal Kumaran]

----- Original message -----
> In article <mailman.1105.1279945954.1673.python-list at python.org>,
>   Kushal Kumaran <kushal.kumaran+python at gmail.com> wrote:
>
> > In general, after select has told you a descriptor is ready, the
> > first write after that should always succeed.
>
> <snip>
>
> Consider, for example, a write on a TCP connection.   You are sitting in
> a select(), when the other side closes the connection.   The select()
> should return, and the write should then immediately fail.   If you're
> tempted to say that the select() should return some sort of error,
> consider the case where the remote end closes the connection after the
> select() returns but before your process gets to execute the following
> write() call.
>
> We also saw a case where (due to what we consider a kernel bug), a
> received UDP packet with a checksum error would cause the select() to
> wake up, *then* notice the checksum error and discard the packet, and
> thus the following read() would block.
>
> <snip>

Thanks Roy. That was educational.

--
regards,
kushal
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