How to use a simple Makefile

Updated September 2026 · Beginner-friendly guide

Define a target

A Makefile rule names a target, its prerequisites, and a tab-indented recipe.

CC = cc
CFLAGS = -std=c17 -Wall -Wextra -Wpedantic -g

app: main.o calculator.o
	$(CC) $(CFLAGS) main.o calculator.o -o app

Separate rules rebuild only sources whose prerequisites changed. List headers so edits trigger recompilation.

main.o: main.c calculator.h
	$(CC) $(CFLAGS) -c main.c

calculator.o: calculator.c calculator.h
	$(CC) $(CFLAGS) -c calculator.c

A phony target represents an action rather than a generated file. Keep removal limited to known build products.

.PHONY: clean
clean:
	rm -f app main.o calculator.o

Run make to build the first target, make clean to remove outputs, and make CC=clang to select Clang.

make
./app
make clean
make CC=clang