change of header file detection for makefile

Question

My makefile doesn't detect changes in header files. How can i add this functionality to my makefile? Here is my makefile:

CPP  = g++
CC   = gcc
RES  = 
OBJ  = obj/main.o obj/customfunc1.o obj/customfunc2.o $(RES)
LINKOBJ  = obj/main.o obj/customfunc1.o obj/customfunc2.o $(RES)
LIBS =   
INCS =  -I"lib1/inc"  -I"lib2/inc" 
CXXINCS =  -I"lib1/inc"  -I"lib2/inc" 
BIN  = out
CXXFLAGS = $(CXXINCS)  
CFLAGS = $(INCS)  
RM = rm -f

.PHONY: all all-before all-after clean clean-custom

all: all-before $(BIN) all-after


clean: clean-custom
${RM} $(OBJ) $(BIN)

$(BIN): $(OBJ)
$(CC) $(LINKOBJ) -o $(BIN) $(LIBS)

obj/main.o: main.c
$(CC) -c main.c -o obj/main.o $(CFLAGS)

obj/customfunc1.o: lib1/customfunc1.c
$(CC) -c lib1/customfunc1.c -o obj/customfunc1.o $(CFLAGS)

obj/customfunc2.o: lib2/customfunc2.c
$(CC) -c lib2/customfunc2.c -o obj/customfunc2.o $(CFLAGS)

Answer 1

Header files must be listed together with other dependencies. E.g.:

CPP  = g++
CC   = gcc
RES  = 
OBJ  = obj/main.o obj/customfunc1.o obj/customfunc2.o $(RES)
LINKOBJ  = obj/main.o obj/customfunc1.o obj/customfunc2.o $(RES)
LIBS =   
INCS =  -I"lib1/inc"  -I"lib2/inc" 
CXXINCS =  -I"lib1/inc"  -I"lib2/inc" 
BIN  = out
CXXFLAGS = $(CXXINCS)  
CFLAGS = $(INCS)  
RM = rm -f

.PHONY: all all-before all-after clean clean-custom

all: all-before $(BIN) all-after


clean: clean-custom
${RM} $(OBJ) $(BIN)

$(BIN): $(OBJ)
$(CC) $(LINKOBJ) -o $(BIN) $(LIBS)

obj/main.o: main.c header1.h header2.h
$(CC) -c main.c -o obj/main.o $(CFLAGS)

obj/customfunc1.o: lib1/customfunc1.c lib1/header.h
$(CC) -c lib1/customfunc1.c -o obj/customfunc1.o $(CFLAGS)

obj/customfunc2.o: lib2/customfunc2.c lib2/header.h
$(CC) -c lib2/customfunc2.c -o obj/customfunc2.o $(CFLAGS)