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Re: any way to set an automake variable in a top-level automake file, an
From: |
Ralf Wildenhues |
Subject: |
Re: any way to set an automake variable in a top-level automake file, and have it apply to subdirs? |
Date: |
Sat, 5 Nov 2005 09:10:22 +0100 |
User-agent: |
Mutt/1.5.9i |
Hi Ed,
* Ed Hartnett wrote on Fri, Nov 04, 2005 at 06:15:29PM CET:
> Ralf Wildenhues <address@hidden> writes:
> > * Ed Hartnett wrote on Fri, Nov 04, 2005 at 02:57:44PM CET:
> >>
> >> I find myself setting AM_CFLAGS=-g in many subdirectories.
> >
> > Why not just put
> >
> > AC_SUBST([AM_CFLAGS], [-g])
> >
> > in configure.ac?
> > Note though that many compilers cannot mix -g and optimization options;
> > you should allow the user the override with CFLAGS without breaking this.
>
> How exactly would I be sure to allow that?
The best thing would be to look at the Autoconf macro _AC_PROG_CC_G,
defined in autoconf/lib/autoconf/c.m4 (installed path may be similar to
$prefix/share/autoconf/autoconf/c.m4). Unfortunately, it's not
published interface.
> How does everyone else handle this? Is it usual to turn on -g
> everywhere?
I just would not mumble with AM_CFLAGS at all, unless necessary. If the
user hasn't specified CFLAGS, the configure script will try to enable
one or both of "-O2" and "-g" (both if they work together). As a user,
I can override it by setting CFLAGS appropriately. As a package author,
I'd only override it in case there are compilation errors without or
with a certain option. However, even in that case there are good
arguments _against_ doing so: you (as a package author) have no idea
when a certain compiler bug for example may be fixed. Also, there is a
plethora of different compilers and systems out there.
Cheers,
Ralf