What is the meaning of a variable defined on the same line of a rule targets prerequisites such as "a: x = 0" in GNU Make?

Question

I have seen code like the following following code in a Makefile:

a: x = 0

What does this line mean? Is it a rule, or something else?

If anyone can understand the downvote, please let me know. I want to learn to improve. I never retaliate downvoters who explain. Self answered to help other people in the world gain 15 minutes in their lives by googling keywords :-) — Ciro Santilli Путлер Капут 六四事, Aug 17 '15 at 06:50

score 2 · Accepted Answer · answered Aug 15 '15 at 10:13

It gives a different value to a variable inside a given target.

Sample usage:

x := 0

a: x := 1
a:
    @echo $x

b:
    @echo $x

Now:

$ make a
1
$ make b
0

1 Answers1