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Re: Building C++ with --enable-languages=c,fortran
- From: Ian Lance Taylor <iant at google dot com>
- To: Thomas Koenig <tkoenig at netcologne dot de>
- Cc: gcc at gcc dot gnu dot org, "fortran\ at gcc dot gnu dot org" <fortran at gcc dot gnu dot org>
- Date: Fri, 05 Aug 2011 18:51:12 -0700
- Subject: Re: Building C++ with --enable-languages=c,fortran
- References: <4E3C7412.2010100@netcologne.de>
Thomas Koenig <tkoenig@netcologne.de> writes:
> I just noticed that C++ now appears to be built by default, even when
> only the C and fortran are specified. The configure line
>
>
> ../trunk/configure --prefix=$HOME --enable-languages=c,fortran
> --with-mpc=/usr/local --with-mpfr=/usr/local
>
> leads to the message
>
> checking for version 0.11 (revision 0 or later) of PPL... no
>
> The following languages will be built: c,c++,fortran,lto
>
> I see recent changes by Ian in this area, but nothing in the ChangeLog
> suggests to me that this was intentional.
It is intentional. In current mainline stages 2 and 3 are now by
default built with the C++ compiler, not the C compiler. Therefore, the
C++ compiler must be built in stages 1 and 2, in order to use to build
the stages 2 and 3 compiler. And then of course we build the C++
compiler in stage 3 in order to compare it.
The ChangeLog entry says that if --enable-build-poststage1-with-cxx is
set, C++ becomes a boot language. That is what you are seeing. I guess
what the ChangeLog entry does not say is that
--enable-build-poststage1-with-cxx is set by default.
Ian