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makefiledependenciesgnu-makefile-generation

Makefile: order of dependency evaluation

Assume a target foo.tar, that depends on a list of files foo.files, e.g.

FOO_FILES := $(shell cat foo.files)

foo.tar: foo.files $(FOO_FILES)
    tar -cf foo $(FOO_FILES)

Now suppose that foo.files need to be generated e.g.:

foo.files: foo.files.template
    sed -e "s/@{VERSION}/$(VERSION)/" < $< > $@

It is clear that foo.files depends on foo.files.template, but how can one make sure that FOO_FILES is evaluated after foo.files is generated?

Solution

  • Your original rules are correct. Because updating foo.files causes the value of FOO_FILES to become outdated you just need to make sure your Makefile is re-evaluated by gnu make when foo.files has been updated by making your Makefile depend on foo.files:

    Makefile : foo.files