CODEWITHSUNDEEP
makefilegnu-make
jfMR
jfMR

Reputation: 24778

Preserving trailing slashes of prerequisites in GNU Make 3.81

Consider this very simple makefile:

foo: bar/

Running GNU Make 3.81 on this makefile results in:

make: *** No rule to make target `bar', needed by `foo'. Stop.

As we can see, the trailing / is removed from bar/.

Alternatively, using the --print-data-base or -p option to print the rules resulting from processing this makefile:

$ make -p 2>/dev/null | grep foo:
foo: bar

We can see that the trailing slash is removed from the original bar/. This issue, however, is not present in newer versions of GNU Make (e.g., 4.2.1).

How can I preserve the trailing slash in the name of a rule's prerequisites in GNU Make 3.81?

Upvotes: 2

Views: 148

Answers (1)

Stefan Becker
Stefan Becker

Reputation: 5962

Plain trailing / doesn't seem to be possible, but maybe bar/. will help you? It would require to rewrite all directory targets to include the trailing /.

_empty :=
_space := $(_empty) $(_empty)

.PHONY: bar bar/.
bar bar/.:
       @echo "$@ -> $(dir $@)"

foo: bar/

foo_quoted: "bar/ "

foo_space: bar/$(_space)

foo_space_quoted: "bar/$(_space)"

BAR = "bar/ "

foo_var: $(BAR)

BAR_DIR = bar/

foo_dir: $(dir $(BAR_DIR))

BAR_SPACE = bar/$(_space)

foo_var_space: $(BAR_SPACE)

foo_dot: bar/.

foo_double: bar//

All other attempts will look for bar, i.e. GNU make strips the trailing / when processing the dependencies either during parsing or execution. The foo_dot example on the other hand results in

$ ./make --version
GNU Make 3.81
...
$ ./make foo_dot
bar/. -> bar/

$ make --version
GNU Make 4.2.1
...
$ make foo_dot
bar/. -> bar/

Upvotes: 3

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