One rule in my Makefile zips an entire directory (res/) into a ZIP file. Obviously, this rule needs to execute when any file under the res/ directory changes. Thus, I want the rule to have as a prerequisite all files underneath that directory. How can I implement this rule?
In Bash with the globstar option enabled, you can obtain a list of all the files in that directory using the wildcard pattern res/**/*. However, it doesn't seem to work if you specify it as a prerequisite in the Makefile:
filename.jar: res/**/*
Even after touching a file in res/, Make still reports
make: `filename.jar' is up to date.
so clearly it is not recognizing the pattern.
If I declare the directory itself as a prerequisite:
filename.jar: res
then Make will not re-execute when a file is modified (I think make only looks at the modified date of the directory itself, which only changes when immediate children are added, removed, or renamed).
This:
filename.jar: $(wildcard res/**/*)
seems to work, at least on some platforms.
EDIT:
Or better, just cut the knot:
filename.jar: $(shell find res -type f)