Question

If I have the following rule in a makefile:

$(OBJ)/%.o: $(SRC)/%.c
    $(CC) -c -o $@ $< $(CFLAGS)

Every file matching the prefix ./obj/ and sufix .o will have its stem passed to %, so I can provide some dependencies based on its name.

But, suppose I have this kind of rule, which I specify one by one the targets I want:

OBJECTS=abc.o bca.o cba.o
$(OBJECTS): $(SRC)/%.c
    $(CC) -c -o $@ $< $(CFLAGS)

How do I make the % stem actually work for the current target name make is executing? Just using % doesn’t work, neither $@.

Note that I’m trying to write the actual target name to its own dependency. For example, when make is executing the rule for abc.o, it would include $(SRC)/abc.c and just it (something like $(patsubst %.o, $(SRC)/%.c, MAGIC_TARGET_NAME_VARIABLE)).

Answer 1

You can just replace this rule:

$(OBJECTS): $(SRC)/%.c

with:

$(OBJECTS) : %.o : $(SRC)/%.c

You will need to add the $(OBJ) to the -o part of the recipe if you still want them built there:

$(OBJECTS) : %.o : $(SRC)/%.c
     $(CC) -c -o $(OBJ)/$@ $< $(CFLAGS)