[yocto] How does RRECOMMENDS work?

[Chris Tapp]

Hi Paul,

On 8 Sep 2014, at 09:40, Paul Eggleton <paul.eggleton at linux.intel.com> wrote:

> Hi Chris,
> 
> On Monday 08 September 2014 08:55:15 Chris Tapp wrote:
>> I've got a recipe to which I've added:
>> 
>> RRECOMMENDS_${PN} = "<package>"
>> 
>> The documentation says that "If, during the build, a package from the
>> RRECOMMENDS list cannot be found, the build process continues without an
>> error".
>> 
>> I tried a build without <package> (i.e. no recipe) and it failed with
>> "Nothing provides <package>". Is this the expected behaviour? If so, is
>> there a way I can pull in a package if it is build-able and skip it
>> otherwise?
>> 
>> In this case <package> contains some utilities which can be of help, but
>> they're not required in any way at runtime.
> 
> Scott has just pinged me about this, the manual is slightly misleading. How it 
> works is, if you have an item mentioned in RRECOMMENDS, there must be a recipe 
> that provides that item via RPROVIDES (or indirectly via PACKAGES or 
> PACKAGES_DYNAMIC), otherwise you will receive the error you mentioned. 
> However, if the package does not actually end up being produced, that is OK.
> 
> RRECOMMENDS is generally for things that you normally would expect to be 
> available, but may not be for some reason (e.g. kernel modules that might 
> instead be compiled in and thus are not produced as a package).

That makes sense. Thanks for the clarification :-)

> Cheers,
> Paul
> 
> -- 
> 
> Paul Eggleton
> Intel Open Source Technology Centre

--

Chris Tapp
opensource at keylevel.com
www.keylevel.com