My Makefile is based on multiple variables defined in a configuration file or ENV vars. My current solution is to test all of them manually:
NOGOAL = help clean distclean mrproper
ifeq ($(strip $(filter $(NOGOAL), $(MAKECMDGOALS))),)
VAR1 ?= $(error VAR1 undefined)
VAR2 ?= $(error VAR2 undefined)
VAR3 ?= $(error VAR3 undefined)
...
VARn ?= $(error VARn undefined)
endif
I would like to use a foreach loop instead:
ifeq ($(strip $(filter $(NOGOAL), $(MAKECMDGOALS))),)
TESTVAR = TEST1 TEST2 TEST3
$(foreach v, $(TESTVAR), $(eval $v ?= $$(warning Error: $v undefined)))
endif
Unfortunately eval doesn't work as I expected. Did I miss something?
Here a full test of my tests with 2 implementations of the tests. Even if TEST3 is not defined I don't get any error
TEST1 = 1
TEST2 = 1
#TEST3 = 1 # NOT DEFINED
TESTVAR := TEST1 TEST2 TEST3
# First implementation
$(foreach v, $(TESTVAR), $(eval $v ?= $$(warning Error: $v undefined)))
# Second implementation
$(foreach v, $(TESTVAR), $(eval $(call TESTER,$v)))
define TESTER
ifndef $1
$(warning $1 not defined)
endif
endef
# Dummy rule
all:
@echo Hello World
However, my first implementation works if I use $(TEST3) somewhere.
EDIT
Here I get no error but TEST3 is not defined:
~$ cat Makefile
TEST1 = 1
TEST2 = 1
#TEST3 = 1 # NOT DEFINED
TESTVAR := TEST1 TEST2 TEST3
# First implementation
$(foreach v, $(TESTVAR), $(eval $v ?= $$(warning Error: $v undefined)))
# Dummy rule
all:
@echo Hello World
~$ make
Hello World
Well, I guess I don't get it. Your original version, that you say works the way you want it, will not print any warnings unless you USE one of the variables which is not defined. Your first alternative with foreach works the same way: it will print a warning but only when you use the variable that's undefined.
If you want it that way, then testing for clean, etc. doesn't really make much sense since presumably those rules won't use the variables that are not defined so you won't get any errors (and if they did use the variables that weren't defined, presumably you'd want those rules to fail as well).
But in your second edit, you say that you want the make to fail immediately if the variables are not defined, regardless of whether or not they're used (in your last example you don't define TEST3, but you don't use TEST3 for anything either so no warning is printed). If that's what you want I don't see why you are assigning values to the variables with ?= at all, or using eval. Just write something like:
ifeq ($(strip $(filter $(NOGOAL), $(MAKECMDGOALS))),)
$(foreach v,$(TESTVAR),$(if $($v),,$(error Error: $v undefined))
endif
(In this version you do need to check MAKECMDGOALS since it fails immediately on an unset variable).
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