Re: [PATCH 0/5] x86/pci: patches for tip/x86/unify-pci

From: Sam Ravnborg
Date: Fri Jul 11 2008 - 06:28:09 EST


> >
> > obj-y is empty when you enter the Makefile.
> > So if you start out with ':=' or '+=' is no difference.
>
> i guess it's safer to use +=, because it's ordering invariant.
>
> We should use := only if we absolutely want to override the current
> rules.

In the past I was carefully to use ':=' for the first assignmnet so the
variable was a " simply expanded variables" variable.
But as I have added a 'obj-y := ' in kbuild we should
be safe.

" simply expanded variables" is some special make stuff.

A typical:

FOO = bar

is a "recursively expanded variable".
Here the assingment is evaluated on each usage.

Sam
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