Re: [Vala] Rules for updating generated C files

[Jan Hudec <bulb ucw cz>]

On Tue, Jun 08, 2010 at 22:58:09 +0200, Jürg Billeter wrote:
> On Tue, 2010-06-08 at 13:36 -0700, Robert Powell wrote:
> > You snipped the important bit "For this simple system, it would be easy
> > enough to update the makefile to watch for this dependency."  It was meant
> > to illuminate the fact that when systems get larger, trying to maintain
> > dependencies becomes terribly complicated.

I would never ever consider maintaining the dependencies manually an option
even for single source. The techinque using gcc -M is reasonably easy and
reliable.

> > I suggested a solution for the problem.

Unfortunately it was not a solution. If the dependent code is compiled in
separate step and the chage does not induce change in content of the .c file,
valac wouldn't know to touch the output anyway.

> > Does anyone have any better
> > suggestions (other than use automake--automake is not an option for our
> > projects here) for dealing with larger systems?
>
> You could use a similar approach and use gcc -M or makedepend to
> generate Makefile rules describing header file dependencies. The
> Makefiles would certainly get a bit more complicated but it should be
> possible and not require manual dependency maintenance. If that's
> possible, I'd prefer to keep the simple update logic we currently have
> in valac.

As far as I can see there is no way to detect dependencies correctly short of
full preprocess of the C file. That is IMO outside of scope of valac.

On the other hand valac is able to call the C compiler itself and it should
make sure the output is rebuilt correctly when it does. It recompiles
everything everytime though, no?

-- 
                                                 Jan 'Bulb' Hudec <bulb ucw cz>