Re: [Vala] Rules for updating generated C files

[Jürg Billeter <j bitron ch>]

Hi Rob,

On Tue, 2010-06-08 at 13:36 -0700, Robert Powell wrote:
> On Tue, Jun 8, 2010 at 1:23 PM, Jan Hudec <bulb ucw cz> wrote:
>
> > On Thu, Jun 03, 2010 at 14:13:01 -0700, Robert Powell wrote:
> > > If a member variable is added to BaseClass, BaseClass.vapi will change.
> >  The
> > > C file that is generated from Derived.vala will be identical, but it
> > needs
> > > to be recompiled because the base class has changed.  valac will not
> > > regenerate Derived.c because it hasn't changed.
> >
> > The Makefile in your example is hopelessly broken. Derived.c has not
> > changed,
> > but it certainly includes BaseClass.h which must have had. The makefile
> > fails
> > to see that Derived.o depends on BaseClass.h and the fix should be to make
> > the makefile directly aware of the fact.
> 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 suggested a solution for the
> problem.  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.

Jürg