How to make a single “makefile” create 3 output binaries

Question

could anyone help me create a makefile for my project? I need 3 binaries to be created from the makefile.

The binaries compile individually like this:

gcc -D_POSIX_SOURCE -Wall -Werror -pedantic -std=c99 -D_GNU_SOURCE -pthread main.c service_client_socket.c service_listen_socket.c get_listen_socket.c -o serverThreaded

gcc -D_POSIX_SOURCE -Wall -Werror -pedantic -std=c99 -D_GNU_SOURCE -pthread main.c service_client_socket.c service_listen_socket.c get_listen_socket.c -o server

(So it creates 2 identical binaries but with different names, serverThreaded and server)

and also I need this from the makefile too:

gcc -D_POSIX_SOURCE -Wall -Werror -pedantic -std=c99 -D_GNU_SOURCE -pthread client.c -o client

Edit: I think this is what I need?

all: serverThreaded server client

    gcc -D_POSIX_SOURCE -Wall -Werror -pedantic -std=c99 -D_GNU_SOURCE -pthread main.c service_client_socket.c service_listen_socket.c get_listen_socket.c -o serverThreaded 
    gcc -D_POSIX_SOURCE -Wall -Werror -pedantic -std=c99 -D_GNU_SOURCE -pthread main.c service_client_socket.c service_listen_socket.c get_listen_socket.c -o server 
    gcc -D_POSIX_SOURCE -Wall -Werror -pedantic -std=c99 -D_GNU_SOURCE -pthread client.c -o client 
    .PHONY: all

Answer 1

You can add a phony rule (that is a rule that doesn't build a file itself) which has whatever you want to build as its prerequisites. By convention, this rule is called all in most Makefiles. For your case, it would look like this:

all: serverThreaded server client

It's also common to put this as the very first rule , so if you just type make without a target, it is automatically selected.

An important thing to do is to let make know this rule actually is "phony" by putting it in the prerequisites of the special target .PHONY like this:

.PHONY: all

This is necessary because otherwise, make would expect it to build a file called all . If you'd ever have a file all in your current directory which is newer than all files you actually build, make wouldn't do anything.

---

Regarding the edit, it doesn't make any sense. Explaining make entirely isn't possible in this Q&A format, so I'll just give you an example how a very basic Makefile could look like, as a start:

CC:= gcc
CFLAGS:= -D_POSIX_SOURCE -Wall -Werror -pedantic -std=c99 -D_GNU_SOURCE -pthread
LIBS:= -pthread

serverThreaded_OBJS:= main.o service_client_socket.o service_listen_socket.o get_listen_socket.o
server_OBJS:= main.o service_client_socket.o service_listen_socket.o get_listen_socket.o
client_OBJS:= client.o

all: serverThreaded server client

serverThreaded: $(serverThreaded_OBJS)
    $(CC) -o$@ $^ $(LIBS)

server: $(server_OBJS)
    $(CC) -o$@ $^ $(LIBS)

client: $(client_OBJS)
    $(CC) -o$@ $^ $(LIBS)

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

clean:
    rm -f *.o

.PHONY: all clean

As a side note, it's strange how your serverThreaded and server are built from the exact same sources with the exact same flags -- you will end up with the exact same binaries.

Answer 2

You can add an artificial target as the first one. By convention, this target is usually called all . Then you can list all the dependencies you actually want to build:

all: serverThreaded server client

See this discussion of the default goal .