[FFmpeg-devel] [PATCH] Fix pkg-config detection when using a cross-prefix

Michael Niedermayer michaelni at gmx.at
Mon Jul 2 21:42:06 CEST 2012

On Mon, Jul 02, 2012 at 01:37:50PM -0400, Kyle Schwarz wrote:
> On 7/2/2012 1:03 PM, Michael Niedermayer wrote:
> >On Fri, Jun 29, 2012 at 10:08:06PM -0400, Kyle Schwarz wrote:
> >>On 6/29/2012 11:04 AM, Michael Niedermayer wrote:
> >>>On Fri, Jun 29, 2012 at 10:58:28AM -0400, Derek Buitenhuis wrote:
> >>>>On 29/06/2012 2:30 AM, Kyle Schwarz wrote:
> >>>>>The attached patch resolves a pkg-config issue.
> >>>>>
> >>>>>When a cross-prefix is used, FFmpeg searches for a cross-prefixed
> >>>>>pkg-config, and fails to use pkg-config if none if found.
> >>>>>
> >>>>>This patch allows a native system pkg-config to be used if a prefixed
> >>>>>one is not found.
> >>>>
> >>>>This seems like it could go quite wrong in some situations...
> >>>
> >>>seconded
> >>
> >>Can you give me an example of when it could go bad?
> >
> >
> >assume you have libfoo 0.1 installed on your host and you cross
> >compile and link to libfoo 9.0.
> >the hosts pkg-config will search the hosts .pc files which will
> >contain "instructions" to link to libfoo 0.1. Thes 2 libs may depend
> >on different other libs, need different linker flags and be in
> >different directories
> The PKG_CONFIG_PATH is what controls where the .pc files are found.
> >The problem i see is not using the hosts pkg-config but rather the
> >hosts installed .pc files. But the hosts pkg-config will use them
> >by default and i dont see something that would prevent it

> As long as the PKG_CONFIG_PATH is set properly the host system libs
> will not be used.

who or what would set this path ?

i think configure doesnt set nor check it (at least my grep failed
to find any indication for it)
a seperate pkg-config binary could use a different path ... so it
wouldnt need PKG_CONFIG_PATH set ...
but if we would use the hosts then it certainly would be bad if the
path isnt set.

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Democracy is the form of government in which you can choose your dictator
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