CODEWITHSUNDEEP
c++cmakefile
Adeeb HS
Adeeb HS

Reputation: 169

Make file for multiple programs

I have p1.c p2.c ... pn.c, a sharedprg.c and a sharedprg.h files in a directory, I want to create a make file to compile all these programs, for example something like this

for i in {1..n}    // just a pseudo code to tell what's in my mind
   gcc -o p$i p$i.c sharedprg.c

And every time I invoke make it should just re compile pi if pi.c changed or-else compile all the programs if either sharedprg.c or shareprg.h changed. Is there any way I can achieve this?

Edit: I would get the result which I wanted using this code

shared = sharedMem.c sharedMem.h
all: p1 p2 p3 

%.o: %.c 
    gcc -c $^

p1: p1.o $(shared) 
    gcc -o p1 p1.o sharedMem.c

p2: p2.o $(shared) 
    gcc -o p2 p2.o sharedMem.c

p3: p3.o $(shared) 
    gcc -o p3 p3.o sharedMem.c

clean:
    rm -f *.o p1 p2 p3

But please suggest if there is a better or easier way (with out adding $(shared) everywhere)

Upvotes: 0

Views: 71

Answers (1)

Andreas
Andreas

Reputation: 5301

If you change the $^ to $< in the compile rule, you can add the extra header prerequisites separately. You can also add prerequisites to multiple targets at once. Some inspiration:

# default target; build all
all: p1 p2 p3

# Fix compile rule to only compile the source (excluding any header prerequisites)
%.o: %.c
    gcc -c $<

# programs depend on their respective .o (Static Pattern Rule)
# https://www.gnu.org/software/make/manual/html_node/Static-Usage.html
p1 p2 p3: %: %.o

# all objects depend on sharedMem.h
p1.o p2.o p3.o: sharedMem.h

# all programs depend on sharedMem.o (which is made from sharedMem.c)
p1 p2 p3: sharedMem.o

The built-in rules do this for you, so you can remove the gcc ... recipe line. If you're a beginner, easiest stick to them. See https://www.gnu.org/software/make/manual/html_node/Catalogue-of-Rules.html

Upvotes: 1

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