On Tue, 2 Jul 2002, Jonathan Lemon wrote:
> On Tue, Jul 02, 2002 at 12:58:24PM -0700, Julian Elischer wrote:
> >
> > On Tue, 2 Jul 2002, Jonathan Lemon wrote:
> >
> > > What do people think about adding the following macro to <sys/queue.h>?
> > > (I don't care much about the name, just the functionality)
> > >
> > > #define TAILQ_FOREACH_TMP(var, tmp, head, field) \
> > > for ((var) = TAILQ_FIRST((head)); \
> > > (var) && (((tmp) = TAILQ_NEXT((var), field)) || 1); \
> > > (var) = (tmp))
> >
> > Certainly this is moving in the right direction..
> > (acknowleging the problem).. It does the job.
> > but if someone knows to use it then they probably also
> > know to use a temp variable themselves.
> >
> > It does work in that there is very little the writer can do to screw this
> > up.
> >
> > The question is simply "is it waranted?"
> > It does add complexity.. I guess it needs to be added to all
> > the other types as well (LIST, STAILQ etc)
>
> Well, as Garrett pointed out, the question also is, "is this correct?"
> It appears that the old behavior of not modifying the list pointer may
> actually be part of the API (although undocumented), and one way to fix
> the problem is to just document the behavior.
>
> Since user programs (like libc_r) may already depend on this, perhaps
> the most prudent choice may be to leave the original behavior alone.
yes.
though the -1s in the kernel showed several bugs where threads were being
handled as if they were on a list when they were no longer on that list.
I'll leave it as part of teh debug code..
which brings up another question,
Do you think I should remove the debug stuff when KSE becomes stable?
Or maybe extend it to the other types.
It was very useful in debugging KSE, showing the last 2 places that
touched the linkages, but it may obscure teh source too much.
thoughts anyone?
> --
> Jonathan
>
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