[Ffmpeg-devel] about ff_check_alignment()

[Mario Rossi]

On Tue Jan 30 13:30:52 CET 2007, Uoti Urpala wrote:

> On Tue, 2007-01-30 at 09:00 +0100, Guillaume POIRIER wrote:
> > On 1/30/07, yubing <trueice at gmail.com> wrote:
> >
> > > I wonder which compiler the developers are using, would you refer an
> > > appropriate compiler to me?
> >
> > gcc 4.2 or 4.3

> You don't need a development branch compiler for proper stack variable
> alignment. GCC 4.1 works. I don't currently have GCC 4.0 (or older)
> installed, it might or might not work.

I have the same warning (about stack not aligned), but only when
running xine (1.1.4).
I'm compiling everything with GCC 4.1.1 (shipped with Fedora Core 5).

Xine contains a copy of ffmpeg which is compiled within xine compilation.
What I've found, is that xine passes this switch to the compiler

-mpreferred-stack-boundary=2

when compiling ffmpeg.

On a small test with a standalone ff_check_alignment(), this switch is
enough to cause the test to fail. The default is =4 (i.e. 16 bytes).

Should I write to xine mailing list?
What happens when the stack is not aligned as ffmpeg expects it to be?

Thanks