[FFmpeg-cvslog] r12165 - trunk/libavcodec/dsputil.c

[Rich Felker]

On Thu, Feb 21, 2008 at 10:35:53PM -0700, Loren Merritt wrote:
> On Thu, 21 Feb 2008, Rich Felker wrote:
> >
> > The const keyword in C is not as strong as in C++. Historically it was
> > just a hint for warning generation and binary sectioning. C99
> > (possibly also C90?) add some teeth but I think it's still iffy to
> > consider const-qualified variables as real constants. They're not
> > usable in certain contexts where a constant is required.
> 
> It doesn't even have to be declared const.
> "static unsigned long pb_7f = 0x7f7f7f7f7f7f7f7fUL" works too: gcc sees 
> that it is never assigned to and thus is in fact constant. (assuming unit 
> at a time, of course)

If I someday switch to gcc 4, -fno-unit-at-a-time is probably the only
hope of building with <= 128 megs of ram. I'd rather not have
gratuitous dependencies on unit-at-a-time for optimal code when it's
trivial to write the optimal version directly.

Rich