There are two types of variable declaration. 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? 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?

This is a crosspost from my TIL What the heck is .PHONY in makefile? I have seen this for so long but I always shrugged off. Whatever that is. Well, finally I decided to learn about it. A bit of introduction to Makefile syntax. target: prerequisites <TAB> recipe The first target in a Makefile will be executed by default when we call make. blah: blah.o cc blah.o -o blah # Runs third blah.