[FFmpeg-devel] [PATCH] Fix warning about decode_mb_skip (in libavcodec/h264.h)

[Michael Niedermayer]

On Tue, Jul 06, 2010 at 01:11:30PM +0100, M?ns Rullg?rd wrote:
> Michael Niedermayer <michaelni at gmx.at> writes:
> 
> > On Thu, Jul 01, 2010 at 11:56:32PM +0100, M?ns Rullg?rd wrote:
> >> Michael Niedermayer <michaelni at gmx.at> writes:
> >> 
> >> > On Tue, Jun 29, 2010 at 10:06:12PM -0700, Eli Friedman wrote:
> >> >> Patch attached; fixes warning "'decode_mb_skip' defined but not used".
> >> >>  As far as I can tell, doesn't have any significant effect on the
> >> >> generated code, since the function in question gets inlined either
> >> >> way.
> >> >
> >> > feel free to add av_unused
> >> 
> >> I'd rather you did one of the following:
> >> 
> >> 1.  If the intent is to inline the function, mark it inline.
> >> 2.  If not, move it to a .c file of your choosing and make it extern.
> >> 3.  If only used from one .c file, move it there.
> >
> > The C language contains (non inline) static functions and they are usefull.
> >
> > Files that use some templating system will sometimes contain functions that
> > are unused in some configurations.
> > It is possible that these functions are static.
> > It is possible that we want these functions to be static, compare the non
> > templated case. By switching from non templated to templated the reasons
> > for a function to be static do not suddenly cease to apply.
> > There is no reason to forbid this combination. Nor is there any reason to
> > throw hours of time at trying to avoid this combiation, this would be
> > like forbidding any other arbitrary feature of the language.
> > also the function might contain a different implementation in different
> > cases of the template making it non static would then not be practical
> > without passing its name through a renaming macro.
> 
> Templating is all well and good, ...
> 
> > and av_unused silences the warning, so we do have a clean solution to get
> > rid of the warning.
> >
> > Also its not much hassle to once in a while run a scipt that checks if
> > av_unused marked symbols are used anywhere.
> > what does that need? 2 grep commands in a loop?
> >
> > I really dont understand what problem you have with simply adding av_unused
> 
> ... but I don't see any templating being done with this function.

there is code specific to interlacing, to b frames to direct spatial mode
in there that we had discussed briefly if we should try to template
on paff / frame types and so on
it also calls fill_decode_caches() which is templated on CABAC/CAVLC already


[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Why not whip the teacher when the pupil misbehaves? -- Diogenes of Sinope
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