makefile_test

Makefile sample, from easy to hard
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#Version 1
test: test.c hellof.c
    gcc -o test test.c hellof.c -I.

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#V2
CC=gcc
CFLAGS=-I.

test: test.o hellof.o
    $(CC) -o test test.o hellof.o $(CFLAGS)

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#V3
CC=gcc
CFLAGS=-I./Include
DEPS = hellomake.h

%.o: %.c $(DEPS)
    $(CC) -c -o $@ $< $(CFLAGS)
######-c: compile without linked
hellomake: test.o hellof.o
    gcc -o test test.o hellof.o -I.

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#V4
CC=gcc
CFLAGS=-I.
DEPS = hellomake.h
OBJ = test.o hellof.o

%.o: %.c $(DEPS)
    $(CC) -c -o $@ $< $(CFLAGS)

hellomake: $(OBJ)
    gcc -o $@ $^ $(CFLAGS)

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#V5
IDIR =./Include
CC = gcc
CFLAGS = -I $(IDIR)

ODIR=./obj
LDIR = ./lib

LIBS = -lm

_DEPS = hellomake.h
DEPS = $(patsubst %,$(IDIR)/%,$(_DEPS))
#    (DEPS)=(% == _DEPS) ? $(IDIR)/% ;
#   $(patsubst (item1),(item2),(dir)) ==> $(dir:%.c=%.o) ==> $(var:a=b) 或 ${var:a=b} : Replace item1 to item2 in dir

_OBJ = test.o hellof.o
OBJ = $(patsubst %,$(ODIR)/%,$(_OBJ))

$(ODIR)/%.o: %.c $(DEPS)
    $(CC) -c  -o $@ $< $(CFLAGS)

hellomake: $(OBJ)
    $(CC) -o $@ $^ $(CFLAGS) $(LIBS)

#   $@ : to put the output of the compilation in the file named on the left side of the :
#   $< :  the first item in the dependencies list
#   $^ :  the left and right sides of the :

.PHONY: clean   # make clean
clean:
    rm -f $(ODIR)/*.o *~ core $(INCDIR)/*~


http://www.cs.colby.edu/maxwell/courses/tutorials/maketutor/