[FFmpeg-devel] [PATCH] fix compilation (was Re: r12489 broke all builds)

[Reimar Döffinger]

On Thu, Mar 20, 2008 at 08:13:47AM +0100, Diego Biurrun wrote:
> On Wed, Mar 19, 2008 at 01:28:25PM +0100, Reimar D?ffinger wrote:
> > On Wed, Mar 19, 2008 at 11:49:13AM -0000, M?ns Rullg?rd wrote:
> > > A more realistic example is a file, let's call it mpeg12data.c, that includes,
> > > say, rational.h, and everything is fine.  One fine day, someone changes
> > > rational.h to require stuff from common.h, without adding the #include
> > > line.  Suddenly, mpeg12data.c fails to compile because it doesn't include
> > > common.h, and has no reason to do so, not directly using any of its symbols.
> > 
> > I do not consider (esp. one-time) compilation errors a big deal.
> > Either way I do not strongly favour either way, I just think that
> > headers-including-headers has a higher probability of "silent" failures,
> 
> What kind of silent failures would that be?

What I gave before, that code was tested with some other header that
included common.h and the breaks due to e.g. WORDS_BIGENDIAN never being
defined when this header stops including it.
Of course forgetting a critical header is possible in all cases, it is
just more likely that it will result in compilation error if headers do
not include things themselves.
Though adding a rule on top of always including config.h or common.h or
something that will make sure this can not happen would work too.