Re: auto-dependency usefulness?

[Russell Shaw]

Bryce Schober wrote:
> When I first looked at the auto-dependency stuff at 
> http://make.paulandlesley.org/autodep.html, I was pretty excited, but 
> now I'm not so sure.  What I'd really like is this:
>
> lib/
>   foo.h
>   foo.c
> src/
>   main.c
>
> In this scenario, foo.h declares a "library" function defined in foo.c. 
> This function is called in main.c, which includes foo.h.  As far as I 
> know, this is the generally accepted way to modularize things.  However, 
> gcc's dependency generation doesn't trace main.c's dependency on foo.c, 
> only on foo.h.  How can this dependency be known?  Or even assumed, 
> given that there is a corresponding .c file for .h file?

main.c doesn't depend on foo.c because you can change the internals
of foo.c but if its interface doesn't change, then main.c would
still be compiled the same. main.c would only be compiled different
if foo.h changed.