[FFmpeg-devel] [PATCH] configure: force erroring out in check_disable_warning() if an option doesn't exists

wm4 nfxjfg at googlemail.com
Fri Oct 13 18:27:55 EEST 2017


On Fri, 13 Oct 2017 16:30:59 +0200
Hendrik Leppkes <h.leppkes at gmail.com> wrote:

> On Fri, Oct 13, 2017 at 4:14 PM, James Almer <jamrial at gmail.com> wrote:
> > On 10/12/2017 6:30 PM, James Almer wrote:  
> >> Should prevent some options from being added to cflags when they
> >> don't exist and the compiler only warns about it.
> >>
> >> Signed-off-by: James Almer <jamrial at gmail.com>
> >> ---
> >> I figure this is safer than adding
> >> -Werror=unused-command-line-argument -Werror=unknown-warning-option
> >> as Ronald suggested.
> >>
> >>  configure | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/configure b/configure
> >> index ade67a31bb..c7962665f1 100755
> >> --- a/configure
> >> +++ b/configure
> >> @@ -6370,7 +6370,7 @@ fi
> >>
> >>  check_disable_warning(){
> >>      warning_flag=-W${1#-Wno-}
> >> -    test_cflags $warning_flag && add_cflags $1
> >> +    test_cflags -Werror $warning_flag && add_cflags $1
> >>  }
> >>
> >>  check_disable_warning -Wno-parentheses  
> >
> > Ping. This or a similar solution has been annoying Clang users for some
> > days now and should be part of the 3.4 release.  
> 
> I wonder if a general -Werror is really "safer", do these tests really
> execute without any other warnings, which might trigger a false
> negative? We're not exactly making it compile a proper source file, so
> it might warn about random things.

The worst case is that warnings are not disabled, so the risk isn't too
high.

If you really wanted to, you could run the check _without_ any
arguments, to see whether this type of checking works. And if that
fails, dunno, explode?


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