make vpath and implicit rules: error

Meson · 12-10-2011, 06:28 PM

I'm having trouble with vpath and implicit rules

Code:

INCLUDE_DIR = inc

INKSCAPE  ?= inkscape
CONVERT   ?= convert

vpath %.png $(INCLUDE_DIR)
vpath %.svg $(INCLUDE_DIR)

.PHONY: all clean allclean

clean:
	$(RM) *.aux *.bbl *.blg *.dvi *.log *.out *.nav *.snm *.toc *.vrb *~
	$(RM) $(INCLUDE_DIR)/*.png

# figures

%.png: %.svg
	$(INKSCAPE) -e $(INCLUDE_DIR)/$@ $<

%-g.png: %.png
	$(CONVERT) -colorspace gray $< $(INCLUDE_DIR)/$@

I have a folder called "inc" with a bunch of .svg files. I have a rule for converting the .svg into a .png and a rule for converting the .png into a grayscale -g.png.

The problem is that making the grayscale PNGs won't always work because make seems to expand all of the recipes at once.

so in a clean working directory

Code:

$ make example-g.png

will expand the implicit targets to

Code:

example.png: inc/example.svg
example-g.png: example.png

but if I first do

Code:

$ make example.png

then making the grayscale png will result in the following make rule

Code:

example-g.png: inc/example.png

Is there a fix for this?

ntubski · 12-10-2011, 10:24 PM

Code:

%.png: %.svg
	$(INKSCAPE) -e $(INCLUDE_DIR)/$@ $<

%-g.png: %.png
	$(CONVERT) -colorspace gray $< $(INCLUDE_DIR)/$@

These rules are incorrect, you have to tell make the correct path to the generated file:

Code:

$(INCLUDE_DIR)/%.png: %.svg
	$(INKSCAPE) -e $@ $<

$(INCLUDE_DIR)/%-g.png: %.png
	$(CONVERT) -colorspace gray $< $@

It's the same problem as this thread.

Meson · 12-10-2011, 10:26 PM

Ah, so it's not really incorrect, but a limitation of make...

Meson · 12-10-2011, 11:26 PM

For anyone passing by. I wanted to preserve the bash-completion of the png files without the dirname, so what I did was:

Code:

%-g.png: %.png
        [[ -f $< ]] && prereq=$< || prereq=$(INCLUDE_DIR)/$<; \
        $(CONVERT) -colorspace gray $$prereq $(INCLUDE_DIR)/$@

I'm not sure if there's a more elegant way to do this.