[yocto] writeup on the mechanics of FILESEXTRAPATHS and bbappend files

[Robert P. J. Day]

On Thu, 18 Apr 2013, Gary Thomas wrote:

> On 2013-04-17 16:26, Trevor Woerner wrote:
> > On Wed, Apr 17, 2013 at 11:12 AM, Gary Thomas <gary at mlbassoc.com> wrote:
> > > I also think it would be good to point out the use of := in the
> > > FILESEXTRAPATHS
> > > assignment and why it's important.
> >
> > Knowing that the := operator will put your directories first is only
> > useful if you also know that the underlying mechanism will take the
> > first such files from the given directories it encounters :-) What's
> > to say bitbake doesn't look at all the directories/files and take the
> > last ones?
>
> This has more to do with how the path is constructed (using _prepend).
>
> My point, which was totally unclear to me when using this line, was
> that with ':=' ${THISDIR} evaluates to the directory that contains
> the .bbappend file (what you want/need) whereas with '=' it evaluates
> to the directory containing the main .bb file.  Incredibly confusing
> if you miss it...

  ah, quite so, must make a note of that. i wonder how many other
places that point should be made forcefully.

rday

-- 

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Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

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