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Created August 30, 2022 19:47
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Makefile check if variable is defined
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make_variable_check.md

Check if variable is defined in a Makefile

Using ifndef

ifndef MY_FLAG
$(error MY_FLAG is not set)
endif

Using custom function

check_defined = \
    $(strip $(foreach 1,$1, \
        $(call __check_defined,$1,$(strip $(value 2)))))
__check_defined = \
    $(if $(value $1),, \
      $(error Undefined $1$(if $2, ($2))))
      
install:
	$(call check_defined, var1)
	$(call check_defined, var2)
	# do stuff here..
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