Makefile Script file to automate program compilation and linking (making) 1. Write the "makefile" 2. Write your programs 3. Run "make" or "make -f makefile" Makefile is a list of rules and commands

Makefile Comments start with "#" # This is a makefile for Hello World application Variable definitions, usually in capital letters CC = gcc Main target definition all: hello1.c Dependency definitions %.o: %.c $(CC) $(CFLAGS) -c $< -o

Special Macros name of target $? Name of depended changed $< name of the first dependent $^ names of all dependents

Inference rules Generalized rule Use % as a wild character %.o: %.c $(CC) $(CFLAGS) –c $< Alternative way.c.o : $(CC) $(CFLAGS) –c $<

Makefile Example (1) #This file contains information used by a program called make to #automate building the program CFLAGS = -g -Wall CC = gcc LIBS = -lm INCLUDES = OBJS = a.o b.o c.o SRCS = a.c b.c c.c prog1.c prog2.c HDRS = abc.h

Makefile Example (2) all: prog1 prog2 prog1: prog1.o ${OBJS} ${CC} ${CFLAGS} ${INCLUDES} -o prog1.o \ ${OBJS} ${LIBS} # The variable has the value of the target. In this case = prog1 prog2: prog2.o ${OBJS} ${CC} ${CFLAGS} -o prog2.o ${OBJS} ${LIBS}.c.o: ${CC} ${CFLAGS} ${INCLUDES} -c $<