problems with makefile

This is a discussion on problems with makefile within the C Programming forums, part of the General Programming Boards category; Hello, I have some problems writing my makefile. I'm newbie writing makefiles because I use to make small programs. I ...

  1. #1
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    problems with makefile

    Hello,

    I have some problems writing my makefile. I'm newbie writing makefiles because I use to make small programs. I have defined a library, functions.h and functions.c that uses the GNU scientific library. And then a program that calls functions from functions.h. My makefile is like this:

    Code:
    SDIR		=	source directory
    
    CC		=	gcc
    CFLOPTS		=	-g
    CFLAGS		=	$(CFLOPTS) -I$(SDIR)
    
    CPROGS		=	main
    
    OBJETOS		=	$(SDIR)/main.o $(SDIR)/funciones.o
    
    all:$(CPROGS) $(OBJETOS)
    
    
    clean:
    	rm -f *.o $(CPROGS)
    
    
    main_RCS:$(OBJETOS)
    	$(CC) $(CFLAGS) -o $@ $(OBJETOS) -lm
    	mv $@ $(SDIR)
    
    funciones_RCS.o:$(SDIR)/funciones.c $(SDIR)/funciones.h
    	$(CC) $(CFLAGS) /usr/local/lib/libgsl.a -o $@ -lm
    	mv $@ $(SDIR)
    
    main_RCS.o:$(SDIR)/main.c $(SDIR)/funciones.h
    	mv $@ $(SDIR)
    I have an error of undefined reference in every gnu scientific library function that I use. Someone can help me?

  2. #2
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    Looks to me like you are not linking with the scientific library when producing the final program (main_RCS).

    --
    Mats
    Compilers can produce warnings - make the compiler programmers happy: Use them!
    Please don't PM me for help - and no, I don't do help over instant messengers.

  3. #3
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    But the final program doesn't use scientific library functions, it only calls one function from funciones.c

  4. #4
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    Quote Originally Posted by bartleby84 View Post
    But the final program doesn't use scientific library functions, it only calls one function from funciones.c
    Yes, but you are not linking functiones.o with a libray until you link it together into the final executable. When you compile the "half-way-step", it will just produce an object file of the C file, and not do any linking.

    If you add -v to the CFLOPTS variable, you will see exactly what the compiler does (which is quite a bit). You should only see a "collect2" stage in the final linking step, which is the target here:
    main_RCS:$(OBJETOS)

    If you see collect2 elsewhere, then you have something else wrong (and it may be that you need a -c on the cases where you produce .o files - without seeing the actual output of what make does when you run it, I can't say for sure if it does the right thing or not).


    --
    Mats
    Compilers can produce warnings - make the compiler programmers happy: Use them!
    Please don't PM me for help - and no, I don't do help over instant messengers.

  5. #5
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    Ok thanks, I'm going to try that!

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