[PATCH 4/4] string: Fix tester build with fortify enable with gcc 6

[Carlos O'Donell]

On 7/25/23 11:16, Adhemerval Zanella via Libc-alpha wrote:
> When building with fortify enabled, GCC 6 issues an warning the fortify
> wrapper might overflow the destination buffer.  However, GCC does not
> provide a specific flag to disable the warning (the failure is tied to
> -Werror).  So to avoid disable all errors, only enable the check for
> GCC 7 or newer.

It's not normal to disable a part of a test depending on the gcc version.

However, keeping the test is better for coverage rather than moving to UNSUPPORTED.

Andreas, As the RM is this OK to push?

LGTM.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

> 
> Checked on i686-linux-gnu.
> ---
>  string/tester.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/string/tester.c b/string/tester.c
> index da42c72141..f7d4bac5a8 100644
> --- a/string/tester.c
> +++ b/string/tester.c
> @@ -385,8 +385,17 @@ test_strncat (void)
>  
>    (void) strcpy (one, "gh");
>    (void) strcpy (two, "ef");
> +  /* When building with fortify enabled, GCC 6 issues an warning the fortify
> +     wrapper might overflow the destination buffer.  However, GCC does not
> +     provide a specific flag to disable the warning (the failure is tied to
> +     -Werror).  So to avoid disable all errors, only enable the check for
> +     GCC 7 or newer.  */
> +#if __GNUC_PREREQ (7, 0)

OK. Disabled test for < GCC 7. This works.

>    (void) strncat (one, two, 99);
>    equal (one, "ghef", 5);			/* Basic test encore. */
> +#else
> +  equal (one, "gh", 2);
> +#endif
>    equal (two, "ef", 6);			/* Stomped on source? */
>  
>    (void) strcpy (one, "");

-- 
Cheers,
Carlos.