We are going to create an executable named myprogram.exe using 3 source files: driver.c, bytes.c, and scantext.c and this is the dependency diagram:

A very basic makefile:

myprogram.exe : driver.o scantext.o bytes.o
	gcc driver.o scantext.o bytes.o -o myprogram.exe

driver.o : driver.c scantext.h bytes.h
	gcc -Wall -Wextra -ansi -pedantic -O -c driver.c -o driver.o

scantext.o : scantext.c
	gcc -Wall -Wextra -ansi -pedantic -O -c scantext.c -o scantext.o

bytes.o : bytes.c bytes.h
	gcc -Wall -Wextra -ansi -pedantic -O -c bytes.c -o bytes.o

clean : 
	rm driver.o scantext.o bytes.o myprogram.exe

rebuild : 
	-$(MAKE) clean
	-$(MAKE) 

# Macros #######################################################################
CC=gcc
CFLAGS=-Wall -Wextra -ansi -pedantic -O
OUTDIR=build/
OBJECTS=$(OUTDIR)driver.o $(OUTDIR)scantext.o $(OUTDIR)bytes.o
EXE=$(OUTDIR)program.exe
ERASE=rm

# Targets ######################################################################
$(EXE) : $(OBJECTS)
	$(CC) -o $(EXE) $(OBJECTS)

$(OUTDIR)driver.o : driver.c scantext.h bytes.h
	$(CC) -c driver.c -o $(OUTDIR)driver.o $(CFLAGS)

$(OUTDIR)scantext.o : scantext.c
	$(CC) -c scantext.c -o $(OUTDIR)scantext.o $(CFLAGS)

$(OUTDIR)bytes.o : bytes.c bytes.h
	$(CC) -c bytes.c -o $(OUTDIR)bytes.o $(CFLAGS)

clean : 
	$(ERASE) $(OBJECTS) $(EXE)

rebuild : 
	-$(MAKE) clean
	-$(MAKE) 

• To build the project, just type:

  make
  

• If the file is named something else, say make-gcc, you would type this:

  make -f make-gcc
  

• By default, make executes the first target, which should be the ultimate goal. Usually, that means linking the final project.
• If you want to execute a different target, you must specify that target name. For example:

  make clean
  

  This would execute the clean target only.
• If you want to override a macro in the file, you must specify it on the command line. For example:

  make CC=clang
  

  This would use the clang compiler instead of the gcc compiler.
• If you want to perform multiple actions (recipes), you must list each one on it's own line. For example (modifying the first example above):

  myprogram.exe : driver.o scantext.o bytes.o
  	gcc driver.o scantext.o bytes.o -o myprogram.exe
  	./myprogram > myoutput.txt
  	diff myoutput.txt output.txt
  	tablen scantext.c
  	tablen bytes.c
  

  This will build the program, myprogram.exe, then run it and redirect the output to myoutput.txt, then diff it with the master output, output.txt, then run tablen on scantext.c and then run tablen on bytes.c.

  You may want to make a separate rule instead for everthing else like this:

  run : 
  	./myprogram > myoutput.txt
  	diff myoutput.txt output.txt
  	tablen scantext.c
  	tablen bytes.c
  

  and then you would execute it by running make like this:

  make run
  

• Online make manual.