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Re: Setting an environment variable while inside a target
From: |
pip9ball |
Subject: |
Re: Setting an environment variable while inside a target |
Date: |
Thu, 19 Feb 2009 21:12:30 -0800 (PST) |
Hi Paul,
Thank you very much for your quick reply! I will try out both of these
methods first thing tomorrow at work.
-Phil
Paul Smith-20 wrote:
>
> On Thu, 2009-02-19 at 19:42 -0800, pip9ball wrote:
>
>> I'm looking for a way to export/set an environment variable while I'm
>> inside
>> a target.
>>
>> test1:
>> export CURRENT_TARGET = $@
>> @printenv | grep CURRENT_TARGET
>>
>> Is this possible?
>
> Each line of a recipe is invoked inside a different shell. If you want
> to set an environment variable inside the recipe, you have to put the
> command on the same line. For example:
>
> test1:
> CURRENT_TARGET='$@' env | grep CURRENT_TARGET
>
> Note that your syntax above is wrong in two ways: first, shell variable
> assignments cannot have whitespace around the "=", and second the
> "export VAR=VAL" form is not portable; since make always runs recipes
> using /bin/sh you should use only portable shell constructs.
>
> Another alternative for GNU make is to use its export keyword, like
> this:
>
> CURRENT_TARGET = $@
> export CURRENT_TARGET
> test1:
> env | grep CURRENT_TARGET
>
> Because you are using "=" and not ":=", the variable won't be expanded
> until the recipe is about to be run, by which time "$@" will be set
> properly.
>
> --
> -------------------------------------------------------------------------------
> Paul D. Smith <address@hidden> Find some GNU make tips at:
> http://www.gnu.org http://make.mad-scientist.us
> "Please remain calm...I may be mad, but I am a professional." --Mad
> Scientist
>
>
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>
>
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