Re: BUG: printf formatting libc.so.6

[Segher Boessenkool]

Bruce Korb wrote:
> Segher Boessenkool wrote:
>
> > > > void main(void) { printf("%1$d %1$c %2$d %2$c\n", 32, 49); }
> >
> > This fails on ancient glibc's, with ancient gcc's, too.
>
> glibc's %n$ formatting was hopeless.  Forget it.

Yes.

> > The failure mode is more apparent on big-endian systems.
>
> but a problem on all endian machines.

Yes.

> > See  union printf_arg  and how it's used in vfprintf.c .
> >
> > The fix is probably to document not to use a positional
> > parameter more than once.
>
> Exactly the implementation problem.  There is no such constraint.
> The contrary is required, in fact.

Fine with me, I won't use it, anyway.  I was just trying to
point out that it's not a GCC problem, but a glibc problem
(the original message and my reply were posted to
address@hidden; for some reason your reply wasn't).


Segher