Makefile: nested dependency

Question

I have a lecture consisting of interconnected tex files. lecture.tex uses pictures in pdf format in /pictures/output folder. They are being produced from tex files in /pictures folder.

lecture.tex
makefile
/pictures
 /output
 01_picture.pdf
 02_picture.pdf
 01_picture.tex
 02_picture.tex
 makefile

I created a makefile for pictures (it works fine):

COMMAND = pdflatex
FLAGS = #-quiet
FILES = $(wildcard ./[0-9]*.tex)
.PHONY = all create_dir
OUTPUTDIR="output"
all: create_dir $(patsubst ./%.tex,./output/%.pdf,$(FILES))
create_dir:
 @if [ ! -d $(OUTPUTDIR) ]; then \
 mkdir $(OUTPUTDIR); \
 fi
./output/%.pdf: %.tex
 $(COMMAND) $(FLAGS) $*.tex
 mv ./$*.pdf ./output
 rm ./$*.aux ./$*.log

Now when compiling lecture, we need to do:

if(any pictures tex files were modified)
 recompile picture pdf
 recompile lecture.tex

I tried to do it with this main makefile:

COMMAND = pdflatex
FLAGS = #-quiet
.PHONY = pictures
all: lecture.pdf
lecture.pdf: pictures lecture.tex
 $(COMMAND) $(FLAGS) lecture.tex
pictures:
 make -C pictures

But it doesn't work. Or maybe, I need just 1 makefile for everything?

Answer 1

Just use one makefile, and express the dependencies correctly:

pictures := pictures
output := $(pictures)/output
PDFLATEX := pdflatex
PDFLATEXFLAGS := #-quiet
COMPILE.pdf := $(PDFLATEX) $(PDFLATEXFLAGS)
pictures_tex := $(wildcard $(pictures)/[0-9]*.tex)
pictures_pdf := $(pictures_tex:$(pictures)/%.tex=$(output)/%.pdf)
lecture.pdf: lecture.tex $(pictures_pdf)
 $(COMPILE.pdf) $<
$(output)/%.pdf: $(pictures)/%.tex | $(output)
 $(COMPILE.pdf) -output-directory $| $<
 $(RM) $(output)/$*.aux $(output)/$*.log
$(output): ; mkdir -p $@

• user4035: Is it possible to tell make that it must use files in pictures folder? I don't see it in your makefile.
• user4035: There are some pictures, that use internal files located in pictures folder. I tried cd pictures && $(COMPILE.pdf) -output-directory $(OUTPUT) $<, but it gives an error: pictures/01_picture.tex not found as we are inside pictures folder. Or maybe, accept your answer and write this as a separate question?
• user657267: I'm not that familiar with tex, there should be an option to change the working and/or include directory though.