On Sun, 2014-05-11 at 00:31 +0200, pet...@technux.se wrote:
> 2014-05-10 18:58 skrev Khem Raj:
>
> > On Sat, May 10, 2014 at 1:05 AM, Petter Mabäcker <pet...@technux.se>
> > wrote:
> >
> >> +FILESEXTRAPATHS_prepend := "${THISDIR}/systemtap:"
> >
> > would something like
> >
> > FILESEXTRAPATHS =. "${FILE_DIRNAME}/systemtap:"
> >
> > avoid the prepend and immediate evaluation
>
> I guess someone with deep bitbake knowledge can answer this better. But
> as far as I understand, you should always use immediate evaluation when
> using THISDIR, to be extra safe. Not sure if it's more safe to use
> FILE_DIRNAME if you want to avoid immediate expanding when using
> FILESEXTRAPATHS?
>
> The bitbake documentations says:
>
> "The operators "_append" and "_prepend" differ from the operators ".="
> and "=." in that they are deferred until after parsing completes rather
> than being immediately applied."
>
> Not sure if above means that "=." will also immediately expand
> variables or not?
They're not.
> Personally I have always used FILESEXTRAPATHS_prepend :=
> "${THISDIR}/<somename>:" like the yocto documentation recommends. But
> sure if you can avoid immediate expanding in FILESEXTRPATHS, that would
> mean a tiny optimization. In that case perhaps the documentation should
> be updated as well. Looking in meta-layer both methods seems to be used.
What Khem means is that in the case we know we're in the .bb file
directory, we can use FILE_DIRNAME instead of using :=.
Why? FILE_DIRNAME is defined as:
conf/bitbake.conf:FILE_DIRNAME = "${@os.path.dirname(d.getVar('FILE'))}"
FILE will point to the .bb file.
Cheers,
Richard
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