[FFmpeg-devel] [RFC] full paths in #include directives

[Diego Biurrun]

On Thu, May 08, 2008 at 01:36:11AM +0100, M?ns Rullg?rd wrote:
> Diego Biurrun <diego at biurrun.de> writes:
> 
> > I would like to propose using full paths in all #include directives in
> > FFmpeg, i.e.
> >
> > #include "libavutil/common.h"
> >
> > instead of
> >
> > #include "common.h"
> >
> > The reasons are manyfold:
> >
> > 0) We already expect this from external users.
> >
> > 1) Many header names are not at all unique.  The above-mentioned
> > common.h comes to mind, as do others.  Depending on the order of -I
> > flags the right header may or may not be included.
> >
> > This has bitten me several times in MPlayer already.  We now use full
> > paths for FFmpeg #includes in MPlayer, but still -I flags are needed so
> > that the FFmpeg headers themselves can find their dependencies.  But
> > with -Ilibavcodec on the gcc command line '#include <png.h>' picks up
> > the FFmpeg version instead of the libpng header.  Build system kludges
> > can work around this, but the system remains brittle, future FFmpeg
> > changes may necessitate more or updated kludges.
> >
> > 2) The need for -I flags would be reduced internally as well as
> > externally.
> >
> > Attached is an example patch for libpostproc.  If the idea is accepted,
> > I will do the rest of the work myself.
> 
> I say go ahead.  Headers in the same directory as the file containing
> the #include directive probably don't need the full paths.  The C99
> standard leaves it implementation-defined where header files are
> searched for.  POSIX does, however, specify that the directory of the
> source file be searched first when the #include directive uses
> double-quotes.

So it may be slightly less portable to use full paths everywhere?  I say
we go with full paths everywhere then.  It will also make things look
slightly more consistent.

Diego