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Date: Fri, 22 Feb 2013 00:01:58 +0100
From: Michal Marek <mmarek@suse.cz>
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Subject: Re: How to share variables with a sub-make command in a Kbuild Makefile?
References: <CAD=GYpa5OTy8Jd4Pevgabvc0J+mx6Ba+_K8iAsGPwD3Bc7hknw@mail.gmail.com>
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To: Joel A Fernandes <agnel.joel@gmail.com>
Cc: linux-kbuild@vger.kernel.org

On 9.2.2013 17:34, Joel A Fernandes wrote:
> Hi,
> I am trying to create a patch that involves a call to a submake and
> sharing a variable with it.
> 
> The the top level Makefile is arch/arm/Makefile and has something like:
> dtbs: scripts
>    $(Q)$(MAKE) -e $(build)=$(boot)/dts MACHINE=$(MACHINE) dtbs
>    # Make use of share-var modified by the submake
>    echo $(share-var)
> 
> In the sub-make Makefile, I want to modify a variable and have it
> reflect in the top Makefile
> dtbs: $(addprefix $(obj)/, $(dtb-y))
>    $(Q)rm -f $(obj)/../*.dtb
>    share-var += "new stuff"

This is not possible, because we run a separate make process for every
subdirectory.

Michal