On Sat, 2012-12-29 at 14:27 -0800, Roland Dreier wrote:
> On Sat, Dec 29, 2012 at 12:08 PM, Joe Perches <j...@perches.com> wrote:
> > Sylvan Munaut did something similar
> > https://lkml.org/lkml/2012/12/5/168
>
> Missed that and duplicated the debugging :(
> Sorry Sylvain.
>
> I guess my patch may be preferable, since I happened to use the snprintf()
> method that you suggest -- all the open-coded digit-counting seems a bit
> verbose and perhaps hard to read and see the equivalence to the sprintf.
the kernel implementation of snprint/vsnprintf does expand on c99
and allow snprintf(NULL, 0... so your code should work fine.
I think the
snprintf(NULL, 0
might be suspect.
(the same form is already used in drivers/usb/gadget/composite.c)
man snprintf says in part:
Concerning the return value of snprintf(), SUSv2 and C99 contradict
each other: when snprintf() is called with size=0 then SUSv2 stipulates
an unspecified return value less than 1, while C99 allows str to be
NULL in this case, and gives the return value (as always) as the number
of characters that would have been written in case the output string
has been large enough.
If not here, maybe the tools/perf/util/values.c code
that uses the same form might need changing.
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