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Re: target-specific variables
From: |
Der Herr Hofrat |
Subject: |
Re: target-specific variables |
Date: |
Sun, 14 Mar 2004 20:38:22 +0100 (CET) |
> >>> I'd still like to use the $(shell ...) stuff and define a variable,
> >>> but only if the target t1 is executed. Is there any trick to achieve
> >>> that?
> >>
> >> ohh, i guess = instead of := does the trick, although the
> >> shell-command will be executed many times if the variable is used many
> >> times.
> >
> > It seems clearly documented to me, but here's an example anyway:
> >
> > [exmaple]
>
> what about the $(shell ..) stuff i used in my example?
> of course target-specific variables work like in you example, but
> although not needed,
> t1: TEST:=$(shell find)
> would cause find to be executed no matter which make-target i run.
> That's the point i want to avoid. I only want the shell-command to be
> run once and only if a specific make-target is run.
>
> TEST=$(shell find) is a workaround in my case, since i use $(TEST) only
> once, but if i would use it multiple times, the shell-command would also
> be executed multiple times. That's again something, that i don't want.
> The shell-command should be executed only once.
>
Should be no problem for GNU make.
info make -->
* Using Variables:: -->
* Target-specific::
...
Set a target-specific variable value like this:
TARGET ... : VARIABLE-ASSIGNMENT
or like this:
TARGET ... : override VARIABLE-ASSIGNMENT
Multiple TARGET values create a target-specific variable value for
each member of the target list individually.
The VARIABLE-ASSIGNMENT can be any valid form of assignment;
recursive (`='), static (`:='), appending (`+='), or conditional
(`?='). All variables that appear within the VARIABLE-ASSIGNMENT are
evaluated within the context of the target: thus, any
previously-defined target-specific variable values will be in effect.
Note that this variable is actually distinct from any "global" value:
the two variables do not have to have the same flavor (recursive vs.
...snip...
hofrat
Re: target-specific variables, Ken Smith, 2004/03/15