make, into another directory

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Newsgroups: comp.unix.programmer
Date: Sun, 13 Apr 2003 03:30:12 GMT

I am having difficulties writing a make file that generate files in alternative directories. The problem is mainly on how to generate files from generated files.

Here is an example:

all of .o files from .c files should go to gen/obj directory
all of .c files from .l files should go to gen/src directory

Seems to me that a simple

%.o: %.c

rule can't cover the above two cases. So I'm currently writing two separated rules for it. I want to know that if this (two separated rules) is the only solution?

Thanks for your input, even a 'yes' would help. :-)

make, into another directory

Yes. (Seriously…)

(two separated rules is the only solution)

Paul D. Smith @gnu.org Find some GNU make tips at: http://www.gnu.org http://make.paulandlesley.org

make, into another directory

> %.o: %.c
>   gcc -c $CFLAGS $^ -o $@ ;\
>   mv -f $@ obj

That does not work so well since it makes the .o file allways out of date.

These are the kinds of rules the OP will need.

obj/%.o : %.c
        gcc -c $CFLAGS $^ -o $@

obj/%.o : src/%.c
        gcc -c $CFLAGS $^ -o $@

src/%.c : %.l
        lex $LEXFLAGS $^
        mv -f lex.yy.c $@

Gianni Mariani