[yocto] Difference between target, cross, native and nativesdk.

[Raphael Philipe]

Thank you Paul,

On Tue, Jan 20, 2015 at 10:23 AM, Paul Eggleton
<paul.eggleton at linux.intel.com> wrote:
> Hi Raphael,
>
> On Tuesday 20 January 2015 09:17:49 Raphael Philipe wrote:
>> I'm working on a set of recipes that must be configurable to be baked
>> in native, nativesdk, cross and target.
>>
>> I have a bunch of questions concerning this terms. I searched the
>> documentation and wasn't able to find a definitive explanation for
>> these terms.
>>
>> I will write some statements bellow about my understanding on these
>> terms, and I will ask you to please correct me if I'm wrong or add any
>> additional information:
>>
>> - By default, recipes bake binaries for the target architecture that
>> is described in the MACHINE variable in the local.conf
>
> Correct.
>
>> - One can use BBCLASSEXTEND = "native nativesdk" to bake binaries for
>> the host architecture (native) and for target sdk architecture. The
>> target sdk architecture is described in the SDKMACHINE variable and
>> the host architecture is the architecture of the machine executing
>> bitbake. BBCLASSEXTEND = "native nativesdk" will alow you to bake
>> recipes that are "virtual" using the suffix native ( so ${PN}-native)
>> and the prefix nativesdk (so nativesdk-${PN}).
>
> Correct. FYI alternatively you can also "inherit native" or "inherit
> nativesdk" to make a recipe specific to either of those classes (in which case
> the recipe itself should be named <something>-native or nativesdk-
> <something>), however BBCLASSEXTEND is preferred these days.
>
>> - Recipes that are cross need to inherit cross.bbclass. They are used for
>> ????
>
> Cross tools, i.e. tools that need to run in the native context and produce
> some binary output for the target.

For u-boot-fw-utils-cross, the binary that you refer is the enviroment
variables file of u-boot? In this case, the difference between cross
and native is not clear for me.

>
>> I'm looking for the reason why there is a u-boot-fw-utils and a
>> u-boot-fw-utils-cross. One produces a binary for the target and the
>> other for???
>
> Here's the start of the discussion that precipitated this move:
>
>   http://lists.openembedded.org/pipermail/openembedded-core/2013-September/084280.html
>
> Cheers,
> Paul
>
> --
>
> Paul Eggleton
> Intel Open Source Technology Centre