CODEWITHSUNDEEP
makefilegnu-make
Node.JS
Node.JS

Reputation: 1570

Makefile: variables don't get expanded correctly

I am having a problem with this Makefile structure.

make commit.install should create foo.txt and then put it into some folder. However, make doesn't call the target that creates foo.text. This means I have to call make foo.txt to create the file itself and then call make commit.install to copy this over. I think there is a problem with make not expanding variable dependencies.

./common.mk

src.install: ${INSTALLSRC}
        mkdir -p result
        for f in ${INSTALLSRC}; do \
                cp -a $$f result/.; \
        done

commit.install: src.install
        echo "finished"

clean:
        rm -rf result

./inner/nested/GNUmakefile

include ../common.mk

include Makefile

./inner/nested/Makefile

SRC=foo.txt

foo.txt:
        echo "hello world" > foo.txt

./inner/common.mk

include ../../common.mk

INSTALLSRC=${SRC}

Repository

Upvotes: 0

Views: 811

Answers (1)

Beta
Beta

Reputation: 99084

The problem is that you define INSTALLSRC after the rule that has it as a prerequisite. So when Make evaluates the prerequisite list, the variable is empty, so Make sees no need to build foo.txt. This would have been pretty obvious if you had simplified this collection of makefiles.

The fix is simple; swap the two lines in inner/common.mk:

INSTALLSRC=${SRC}

include ../../common.mk

and GNUMakefile:

include Makefile

include ../common.mk

Upvotes: 1

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