Re: [PATCH] [RFC] notify userspace about time changes
From: Kay Sievers
Date: Thu Aug 05 2010 - 18:40:31 EST
On Fri, Aug 6, 2010 at 00:34, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> On 08/05/2010 03:22 PM, Kay Sievers wrote:
>> I think that's really awkward interface, to pass file descriptor
>> numbers around and write them to magic sysfs files.
>> I would very much prefer a file that contains the current time, and
>> wakes up possible users with a POLL_ERR on changes caused by some
>> other process. That works very well for things like /proc/mounts, is
>> easy to get, and does not need a full page of weird instructions to
>> get stuff done. :)
> Okay, what's wrong with having a file descriptor that gets *written to*
> on a notification?
Because it needs documentation, and is just not needed for such a
simple thing, I think. Why would you want to write a fd number to a
magic file, which can be your fd right away, even passing you the data
> Why POLL_ERR?
Because normal files can not be poll()ed, and it's not that new data
has arrived, it just tells you to rewind and read it again. It's
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