Re: [PATCH 1/1] newlib/libc/include/setjmp.h: Add returns_twice attribute to setjmp()

On Wed, Oct 1, 2025 at 2:23 AM Torbjorn SVENSSON <
[email protected]> wrote:

> Hi Joel,
>
> On 2025-09-30 16:49, Joel Sherrill wrote:
> > The setjmp() function needs this attribute to help GCC avoid false
> > positives for the -Wclobbered warning. The -Wclobbered warning is
> > part of -Wextra.
> > ---
> >   newlib/libc/include/setjmp.h | 7 ++++++-
> >   1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/newlib/libc/include/setjmp.h b/newlib/libc/include/setjmp.h
> > index a2830b275..5c16321a4 100644
> > --- a/newlib/libc/include/setjmp.h
> > +++ b/newlib/libc/include/setjmp.h
> > @@ -17,7 +17,12 @@ void       longjmp (jmp_buf __jmpb, int __retval)
> >   #else
> >   void        longjmp (jmp_buf __jmpb, int __retval);
> >   #endif
> > -int  setjmp (jmp_buf __jmpb);
> > +
> > +#ifdef __GNUC__
> > +int  setjmp (jmp_buf __jmpb)
> > +                     __attribute__ ((returns_twice));;
>
> I suppose you only want a single semi-colon here.
>

Yes. Thanks.

>
> > +#else
>
> I think you should also drop the empty "#else" block.
>

It was supposed to have a setjmp() prototype without the attribute. This
is following the pattern above with longjmp() which has it this way.

v2 will fix these.

--joel

>
> Kind regards,
> Torbjörn
>
> > +#endif
> >
> >   _END_STD_C
> >
>
>