### GC: Makefile loop math

This weeks the Geek Challenge is brought to you by the letter 'M', mmmm makefiles are fun.

Somehow I have taken on the joy of answering makefile questions which more time than not really turn in to scripting questions and just how to do it in a makefile. Here is one that I recently worked on:

How can I set and use a variable inside a loop in a makefile so that var1=var2\*var3, where var2 is update in the loop?

ARY1=1 2 3 4 5
VAR3=2
loop:
@for i in \$(ARY1); do \\
(VAR1=\$(VAR3)\*\$\$i ; \\
echo \$(NP) ; \\
done;
So there it is. The problem has been solved but I thought I would throw it out to the Geek Challenge as well and see what you all come up with. I will post what we used in a couple of days.

For what it's worth.

Well since no one has posted what they thinks might be a solution, I will post what we used as a solution.

ARY1=1 2 3 4 5
VAR3=2
loop:
&nbsp;&nbsp;&nbsp;&nbsp;@for i in \$(ARY1); do \\
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(VAR1=\$(VAR3)\*\$\$i ; \\
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;echo \$\$NP ; \\
&nbsp;&nbsp;&nbsp;&nbsp;done;

Note the double \$ on the NP inside the loop when you want to use the assigned variable.

dl

Posted by Dan Lacher on December 16, 2005 at 04:22 AM EST #

Comments are closed for this entry.

dlacher

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