Re: Conditional change of C++ compiler flags

[Ralf Wildenhues]

Hello Alex,

* Alex Farber wrote on Wed, May 26, 2010 at 07:24:14AM CEST:
> I want to add --enable-debug switch to my configure script, which replaces
> default "-g O3" compiler options with "-g3 -O0". My attempt is obviously
> incorrect:
> 
> AC_ARG_ENABLE( debug,
>     [  --enable-debug,  Enable debug build],
>     [ CXXFLAGS="${CXXFLAGS} -g3 -O0"] )
> 
> This gives compiler command line: "-g O3 g3 -O0" instead of desired "-g3
> -O0"
> Also, automake manual doesn't recommend to touch CXXFLAGS variable, leaving
> it completely to user. What is correct way to do this?

We should have a FAQ entry for this, it comes up every other month.
Any takers?  Last instance was this (although the FAQ entry should
probably be a bit more verbose):
http://thread.gmane.org/gmane.comp.sysutils.autoconf.general/12996/focus=12998

Hope that helps.

Cheers,
Ralf