Messages in this thread | | | Date | Mon, 8 Nov 1999 21:46:05 +0100 (CET) | From | Robert de Vries <> | Subject | Re: [PATCH] POSIX timers for 2.3.25 |
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On Mon, 8 Nov 1999, Matthew Wilcox wrote:
> On Sun, Nov 07, 1999 at 06:33:43PM +0100, Robert de Vries wrote: > > On Sun, 7 Nov 1999, Matthew Wilcox wrote: > > > > > On Sun, Nov 07, 1999 at 05:59:12PM +0100, Robert de Vries wrote: > > > > The siginfo structure is slightly changed. It moves si_value out of the > > > > _rt part of the union. si_value is used both by _rt and _timer and must > > > > map to the same field. > > > > > > You can't do this. You've just broken binary compatibility with any > > > application that uses POSIX RT signals. I can't see a nice way of doing > > > this though. Can anyone else? > > > > IMHO, NOT doing this now gives more problems that doing it "right" at this > > point. I must admit I am not very comfortable with this change either, > > but I don't see any other way, which is not kludgy. > > I'm open to suggestions. I would really not have two _sigval's in two > > structs in the same union. But then again, is it worth breaking a few > > apps at this point? > > If this _really_ needs doing then we need a PER_NEWLINUX, change the > kernel internal structures to the way you want, then translate the > structures to the appropriate form for old Linux binaries whenever > delivering a signal. It'll be unpleasant.
This _really_ needs doing, because not only RT signals issued by sigqueue and the timers need this sigev_value, but also signals sent by completion of asynchronous I/O and by the arrival of a message on an empty POSIX message queue.
The first two are the subject of this discussion now.
The asynchronous I/O at kernel level is curently under development at SGI (see http://oss.sgi.com/projects/kaio) and the POSIX mq_* family will need it next.
The SGI kaio patch currently does not copy the sigev_value into the signal structure, but that's another matter.
I don't know if there are already loads of apps using RT signals out there. A simple recompilation would fix them anyway.
Any RT signal users out there? :-)
Robert
-- Robert de Vries rhdv@rhdv.cistron.nl
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