[OE-core] defining a new image: inherit "image" vs "image_types"?

[Martin Jansa]

On Thu, Jan 10, 2013 at 08:31:52AM -0500, Robert P. J. Day wrote:
> 
>   possibly a distinction with no distinction but i wanted to throw
> together a page on how one defines a new "image type" -- most
> commonly, an SD card image -- and i started with what comes with the
> meta-raspberrypi layer, which seems to work just fine.
> 
>   what i noticed is that that layer introduces the new
> "sdcard_image-rpi.bbclass" class file, which opens with:
> 
> inherit image_types
> 
>   but then i remembered that the meta-ti layer does the same thing,
> providing the new class file "sdcard_image.bbclass" which opens
> instead with:
> 
> inherit image
> 
>   i realize that the oe-core image.bbclass contains this snippet:
> 
> IMAGE_CLASSES ?= "image_types"
> inherit ${IMAGE_CLASSES}
> 
> so it's clear that inheriting "image" is sufficient, but the
> alternative *isn't* clear.
> 
>   what's the preferred construction here?  before digging further to
> see if there's something subtle or equivalent happening, should it be
> sufficient for new image definitions to simply:
> 
> inherit image_types
> 
> ??  have i just not RTFS far enough to see that there's no difference?

did you read image_types.bbclass?

Cheers,
-- 
Martin 'JaMa' Jansa     jabber: Martin.Jansa at gmail.com
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