Minimal example:
$ cat makefile
$(shell rm -rf /tmp/blah)
$(shell mkdir -p /tmp/blah)
ASDF = $(info $1 $(wildcard /tmp/blah/*)
$(if ${BLAH},$(info before $(wildcard /tmp/blah/*)))
$(shell touch /tmp/blah/{a,b,c}.txt)
$(info after $(wildcard /tmp/blah/*.txt))
$ make --version
GNU Make 4.1
...snip...
$ make
after /tmp/blah/a.txt /tmp/blah/b.txt /tmp/blah/c.txt
make: *** No targets. Stop.
$ make BLAH=
before
after
make: *** No targets. Stop.
Take note: I specified different strings in each wildcard:
$(info before $(wildcard /tmp/blah/*))
$(info after $(wildcard /tmp/blah/*.txt))
-brian
On Fri, Nov 30, 2018 at 5:40 AM Gaëtan Harter <gaetan.har...@fu-berlin.de>
wrote:
> Hello,
>
>
> I tried to use `wildcard` in place of doing `ls` and found some
> limitation I did not know about.
>
> I faced the issue that, even with deferred variables, the value of
> `wildcard` was cached to the value it has on first evaluation and does
> not reflect the last state of the filesystem.
>
> Which makes adding `$(info $(VARIABLE_VALUE))` change the behavior.
>
>
> In my case, if I do not want to change the original behavior, I need to
> do twice `ls` to have the initial and the final state, as I cannot
> before running, know the name of the target directory.
> It is generated by `scan-build` that uses a dynamic name.
> I could move it to a fixed name, but that would be working around
> instead of understanding if there is a low level solution.
>
> Also I did not find any reference in the documentation on the behavior
> or any way to force re-evaluating `wildcard` and it took me a while to
> understand what was happening. Maybe I looked in the wrong place and the
> right link would also be a good answer.
>
>
> ### Testing procedure
>
>
> I tested with make from `ubuntu bionic` and also on another machine
> using `arch linux`, so more recent, but do not have the version number.
>
> make --version
> GNU Make 4.1
>
> In the following test snippet [1], I would imagine that doing
>
> make and make EVALUATE_WILDCARD=1 would both work
>
> But when doing `make EVALUATE_WILDCARD=1` the last `test -f` uses the
> value of the first time where `wildcard` was evaluated.
>
> Any hint on how to force the evaluation again, or a way to do twice this
> `ls` without relying on the shell is welcome.
> I know I can just use a fixed name, or use the shell but that would be
> working around before understanding :)
>
>
> Thank you in advance.
>
> Best regards,
> Gaëtan
>
>
> 1:
>
> # I am trying to use `wildcard` as a way to do `ls`.
> #
> #
> # This simulate a local use case of `scan-build`.
> #
> # The final name '$(OUTDIR)/*/index.html' is not known in advance.
> # It is generated by 'scan-build' so not predictable directory name.
> #
> # I tried to get the name using `wildcard` but if wildcard
> # is used before, the initial value is returned.
> #
> # Try running 'make' and 'make EVALUATE_WILCARD=1'
>
> OUTDIR = tmp
> OUTPUT_FILE = $(addsuffix /index.html,$(wildcard $(OUTDIR)/*))
>
> # Just be sure about the initial context
> # One file in 'tmp/a/index.html'
> $(shell rm -rf $(OUTDIR)/*)
> $(shell mkdir -p $(OUTDIR)/a)
> $(shell touch $(OUTDIR)/a/index.html)
>
>
> ifneq (,$(EVALUATE_WILDCARD))
> $(info Evaluate `wildcard` before creating the new file)
> $(info OUTPUT_FILE=$(OUTPUT_FILE))
> endif
>
> .PHONY: all create clean
>
> all: create
> test -f $(OUTPUT_FILE)
>
> create: clean
> mkdir -p $(OUTDIR)/b/
> touch $(OUTDIR)/b/index.html
>
> clean:
> rm -rf $(OUTDIR)/
>
>
>
>
>
>
>
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> Bug-make@gnu.org
> https://lists.gnu.org/mailman/listinfo/bug-make
>
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