A Makefile with Multiple Executables

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For this particular case, where each executable has a single source file with .c extension, all you need is a one line Makefile:

all: ex1 ex3

The built-in default rules for make then work already:

$ make
cc -O2 -pipe   ex1.c  -o ex1
cc -O2 -pipe   ex3.c  -o ex3

Behind the scene, make is using the POSIXly mandated built-in single suffix rule

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

Vary the command to your liking with make CC=gcc CFLAGS=-O2 LDFLAGS=-s and similar.

Trivia of the day: in fact, if you are willing to name the targets when invoking make, you can use an empty or even run without any Makefile:

$ make -f /dev/null CC=gcc CFLAGS=-O2 LDFLAGS=-s ex1 ex3
gcc -O2 -s ex1.c  -o ex1
gcc -O2 -s ex3.c  -o ex3
$ rm -f Makefile ex1 ex3
$ make CC=gcc CFLAGS=-O2 LDFLAGS=-s ex1 ex3
gcc -O2 -s ex1.c  -o ex1
gcc -O2 -s ex3.c  -o ex3

Make magic!

As a rule of thumb, don’t reinvent the wheel (or rules), use the rules that are already there. It simplifies your and make’s life a lot. This makes for small and sexy makefiles to impress the ladies with 🙂

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