ifdef ifneq多个条件

In my Makefile I would like to check the following complex condition:

ifdef VAR1 || VAR2 || VAR3
action
endif 

however the documentation says the syntax like that is not supported. So the only simple workaround that came to my mind is to use the concatenation:

ifneq ($(VAR1)$(VAR2)$(VAR3),)
action
endif 

Are there any other more correct solutions?

For the following case:

ifdef VAR1 && VAR2 && VAR3
action
endif 

one need to write

ifdef VAR1
ifdef VAR2
ifdef VAR3
action
endif
endif
endif 

which is also ugly. Are there more elegant alternatives?

makefile make

1 Answer

activeoldestvotes

up vote10down voteaccepted

If your make is GNU-make and all the defined variables include a non-space character, ifdef VAR1 && VAR2 && VAR3 can be written as ifneq ($(and $(VAR1),$(VAR2),$(VAR3)),) On a related note, probably and function requires version 3.81 or later. In case some defined variables may be empty strings, if we prepare the following functions: ifndef_any_of = $(filter undefined,$(foreach v,$(1),$(origin $(v)))) ifdef_any_of = $(filter-out undefined,$(foreach v,$(1),$(origin $(v)))) then the following conditions: ifdef VAR1 || VAR2 ifdef VAR1 && VAR2 can be written respectively as: ifneq ($(call ifdef_any_of,VAR1 VAR2),) ifeq ($(call ifndef_any_of,VAR1 VAR2),)