CODEWITHSUNDEEP
cmakefile
R3troRice
R3troRice

Reputation: 29

How to compile multiple separate C files in a directory using a Makefile?

I have 3 different C files that are in the same directory which I want to compile separately from one another using a Makefile. This is my Makefile:

program1: program1.o
    gcc program1.o -o program1

program1.o: program1.c
    gcc -c program1.c

program2: program2.o
    gcc program2.o -o program2

program2.o: program2.c
    gcc -c program2.c

program3: program3.o
    gcc program3.o -o program3

program3.o: program3.c
    gcc -c program3.c

clean:
    rm program1.o program1 program2.o program2 program3.o program3

When I run the Makefile it only makes the file for program1 and this is the output I get when I run the Makefile:

make: 'program1' is up to date.

Upvotes: 0

Views: 881

Answers (3)

John Bode
John Bode

Reputation: 123458

Mark Tolonen answered your question, but there are some things you can do to clean this up.

make has a number of implicit (built-in) rules that handle basic stuff like this - you don't need to write an explcit rule to build an executable from a lone C file, make already knows how to do that. Your makefile can literally be as simple as

#
# The CC variable specifies what compiler should be used by the implicit rule
#
CC=gcc 

all: program1 program2 program3

And that's it. If you want to specify parameters for the compiler, you can use the CFLAGS variable:

CC=gcc
CFLAGS=-std=c11 -pedantic -Wall -Werror

all: program1 program2 program3

So to build an individual program, you type make program1 or make program2. To build all three, just type make or make all.

Upvotes: 1

YoavKlein
YoavKlein

Reputation: 2703

If what you mean by "compile separately" is that you want to have the ability to compile them one at a time, then you can invoke you makefile with your desired target like this:

~$ make program2

or

~$ make program3

By default, make invokes the first target in the makefile

Upvotes: 0

Mark Tolonen
Mark Tolonen

Reputation: 177665

make builds the first target given no other arguments, Pass an argument to build a particular target, or add a first line making the executables a dependency of a rule to build them all by default.

all: program1 program2 program3

Upvotes: 2

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