[yocto] What are _virtual providers? and other Suffixes?

[Paul Eggleton]

Hi Brad,

On Tuesday 20 August 2013 23:42:36 Brad Litterell wrote:
> Thanks - that makes it clearer.  But now I have one other question to ask:
> 
> if  virtual/xyz is added to overrides when the item is dealt with, then in
> that case P_P_virtual/xyz_am335 has two overrides hanging off of the base
> variable PREFERRED_PROVIDER.
> 
> You also said earlier that the latest override applies, so is there some
> rule for multiple conditionals on a variable?

Yes, effectively all must be in OVERRIDES for the assignment statement to take 
effect.
 
> E.g. What happens in a case like the following?
> 
> OVERRIDES="foo1:bar2:car3"
> 
> VARIABLE_foo1_bar2 = "both"
> VARIABLE_car3 = "last one"
> 
> what does VARIABLE wind up?  The first is "more specific" in that it matches
> two values in overrides, whereas car is last, but less specific.

I would have thought that the value would have been "last one" however 
experimentation shows that "both" is what you actually get. I'm not exactly 
sure why. In practice I don't think we hit this kind of situation too often 
though, i.e. a mix of double and single overrides where the single override 
needs to take precedence.
 
Cheers,
Paul

-- 

Paul Eggleton
Intel Open Source Technology Centre