Notes on makefile

There are two types of variable declaration.

1. recursively expanded variables - foo is assigned with bar which inturns assigned to ugh whose value is Huh?

foo = $(bar)
bar = $(ugh)
ugh = Huh?

all:;echo $(foo)

$ make
$ Huh?

1. simply expanded variables - foo is assigned with bar however bar is not defined yet. so it outputs to nothing.

foo := $(bar)
bar := $(ugh)
ugh := Huh?

all:;echo $(foo)

$ make
$

NOTE: To echo something it needs to be in a target. Here the target name is all.

If I don’t want to have target and print something I can use warning.

Reference:

https://ftp.gnu.org/old-gnu/Manuals/make-3.79.1/html_chapter/make_6.html

https://www.unix.com/unix-for-dummies-questions-and-answers/104103-how-print-something-make-utility.html

• make
• linux