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

[Måns Rullgård]

Diego Biurrun <diego at biurrun.de> writes:

> On Thu, May 08, 2008 at 03:52:20PM +0200, Aurelien Jacobs wrote:
>> Diego Biurrun wrote:
>> 
>> > 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 like this proposal, but I would prefer if headers in the same
>> directory don't use full path.
>
> Why?  Just to save some characters?  As Mans said, C99 leaves the search
> path implementation defined, so using the full path even for headers in
> the same directory will be slightly more portable.

Well, we already rely on the POSIX -I flag, so we might as well assume
POSIX search order too.

-- 
M?ns Rullg?rd
mans at mansr.com