How do I add dependencies to this header file

Question

Here is a simple header file for six different programs. This Makefile used to work just fine, but then I changed the programs to include other implementation files. This Makefile needs to get changed so that if the implementation files change the files that include those implementation files get recompiled.

all: load list show add delete btree
%: %.cpp
    g++ $< -g -o $@

Answer 1

You can use the -MM option of gcc to create dependency files, and then include those into your Makefile.

TARGETS = load list show add delete btree
all: $(TARGETS)
%: %.cpp
    g++ $< -g -o $@ -MM -MF [email protected]
    sed "s/$@\.o:/$@:/" [email protected] > [email protected]
    -@rm [email protected]

DEPS=$(TARGETS:%=%.d)
-include $(DEPS)

The sed line is present to change the dependency file from load.o: load.c to load: load.c.