Re: How to force a compilation ?

[Ralf Corsepius]

Am Don, 2002-02-14 um 12.51 schrieb BERTRAND Joël:
> Alexandre Duret-Lutz wrote:
> >>>>"bj" == BERTRAND Joël <address@hidden> writes:
> >>>>
> > 
> > [...]
> > 
> >  bj> It works fine. But, when I run "make", a file named rpl.c must
> >  bj> be recompiled. How can I do that ?
> > 
> > What do you mean?  
> > 
> > If rpl.c must be compiled as rpl.o, just list rpl.c in the
> > relevant *_SOURCES variable of your Makefile.am.
> 
> rpl.o is built from rpl.c and rpl.h. But I would recompile this file 
> when "make" is done (even if rpl.o is up to date, because the gcc 
> command line contains "-Ddate=..." which changes.).
When does date change? If your configuration is properly implemented, it
should only change at configuration time and not at build-/make-time.

In this case, putting your "date" into a config-header and let rpl.c
include this. Then, make-dependencies would automatically assure
consistency.

> > If rpl.c must be generated from some other files, list it in a
> > *_SOURCES variable too (or maybe a nodist_*_SOURCES variable)
> > and add a custom rule to build it.
If "date" changes at other occasions but configuration-time, you could
put "date" into a file. let 'rpl.c' include this files and add
appropriate make-dependencies to your Makefile depend on that. However,
this is one magnitude more difficult and error-prone than using a
config-header (E.g. depending on the design of your sources, you might
end with cyclic dependencies)

Ralf