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Re: Clarification on Scoped variables
From: |
Paul Smith |
Subject: |
Re: Clarification on Scoped variables |
Date: |
Fri, 02 Dec 2011 15:24:45 -0500 |
On Fri, 2011-12-02 at 14:42 -0500, AB wrote:
> Hi:
> I wanted to clarify if the following behavior of scoped variables
> (target specific varibles) is by design. Consider the code below,
> where use of the target "a.info" is for collecting meta data about,
> "a" without building "a"
>
> .PHONY : a.info test
> a : var_def := 1
> a :
> @touch $@
>
> # Make var_def visible to a.info
> a : a.info
>
> a.info :
> @echo VAR_INH: $(var_def)
>
> # This does not emit the value of var_def as 1
> test : a.info
>
> As I understand that when Make looks at building a target, it only
> looks at dependencies that effect the target directly or indirectly.
> But this eliminates any scope for looking into any inherited
> variables. Is this by design?
Yes, it's working as expected. The variable inheritance is computed
dynamically as make builds the targets, so it's not sufficient to
declare a prerequisite relationship, you also have to be building the
target as the result of that prerequisite in order to see its variables.
--
-------------------------------------------------------------------------------
Paul D. Smith <address@hidden> Find some GNU make tips at:
http://www.gnu.org http://make.mad-scientist.net
"Please remain calm...I may be mad, but I am a professional." --Mad Scientist