Help getting dependencies working with Makefile

[maxxjr]

I am trying to write a Makefile so that if a header file changes, anything that uses that header file will be rebuilt. I have found a lot of info on the web, but it's not quite working for me.

First question--are there other forums that might be better for this type of question?

If I 'touch' the header file, or if I go in and just add a random character to a comment, no rebuild is done.

Here is my Makefile:

MODULES := AR

LIBS :=

SRCS :=

include Makefile.in

include $(patsubst %, %/module.mk, $(MODULES))

.SUFFIXES: .o .so

%.o: %.cpp
$(CPP) -MMD -c $(INCLUDES) $(CFLAGS) $*.cpp -o $*.o
@cp -f $*.d $*.d.tmp
@sed -e 's/.*://' -e 's/\\$$//' < $*.d.tmp | fmt -1 | \
sed -e 's/^ *//' -e 's/$$/:/' | sort | uniq >> $*.d
@rm -f $*.d.tmp


OBJ := $(patsubst %.cpp,%.o, $(filter %.cpp,$(SRCS)))

depend:

prog: $(OBJ)
$(CPP) -o $@ $(OBJ) $(LIBS)

clean:
rm $(patsubst %.cpp,%.o, $(filter %.cpp,$(SRCS)))

cleanall:
-rm $(patsubst %.cpp,%.o, $(filter %.cpp,$(SRCS)))
-rm $(patsubst %.cpp,%.d, $(filter %.cpp,$(SRCS)))
-rm $(patsubst %.cpp,%.P, $(filter %.cpp,$(SRCS)))

all: prog

-include $(OBJ:.o=.d)

The dependency files generated by the %.o: %.cpp rule looks correct. The rule is based on one of the websites I found in my search (http://make.paulandlesley.org/autodep.html).


The last include is for these dependency files, which contains something like:

object.o: object.cpp header1.h header2.h
object.cpp:
header1.h:
header2.h:

From my research, if header1.h changes, anything that depends on header1.h will be rebuilt. So object.o should be rebuilt. This doesn't happen.

Thanks for any help!

[Some Penguin]

Header files are just header files, not build targets. You don't need a rule for a header file as a target.

You might also want to look into 'makedepend'.