[FFmpeg-devel] [patch] libswscale: fix warning regarding "no return in non void function"

[Dominique Leuenberger a.k.a DimStar]

Quoting Dominique Leuenberger <dominique-ffmpeg-devel at leuenberger.net>:

> In libswscale, in case HAVE_7REGS is not defined to true, there are   
> two functions that result in empty code blocks.
>
> And as a consequence, the compiler warns about no return value in a   
> non void function.
>
> The attached patch fixes this by:
> - Moving the #if HAVE_7REGS out of the function declaraion (meaning   
> the function does not exist at all if we do not HAVE_7REGS.
> - Change some logic to not call the functions if they would not  
> return  useful result anyway.

Just to bring it back to life:
is a compiler warning about an empty function block 'cleaner' than  
avoiding this using an #if directive?

As said: we do have build log checks that fail in various cases known  
to cause program errors: one of them is no return in non-void function  
(which happens to be triggered in this specific case).

Yes, I agree, the compiler might get it wrong. But why not tell the  
compiler that we're smarter? Another day somebody might call the  
function without if (HAVE_7REGS), and then at least the compiler knows  
this is not supposed to be and strictly tells: function is not defined.

Don't only look at the current situation: think a little bit ahead.

Dominique