Re: Default installation directory for include files when cross compiling

[Mark Mitchell <mark at codesourcery dot com>]

Gabriel Dos Reis wrote:
> On Fri, 16 Jun 2006, Mark Mitchell wrote:
> 
> | > | However, in practice, one does want to put multiple targets into a
> | > | single prefix, and that generally works.  That's one reason that cross
> | > | compilers are named $target-gcc; it allows multiple target installations
> | >
> | > cross-compilers are platform-independent, unlike the bulk of libstdc++
> | > headers.
> |
> | I don't know what you mean by platform-independent.  Cross compilers run
> | on one host, and generate code for one target.
> 
> as you may have probably guessed, the qualifier was inverted:
> s/-independent/-dependent/.

OK, I understand what you mean now.

However, I don't think that has any bearing on the issues I've raised.
If you build GCC 4.1.0 with one set of patches for one target, and GCC
4.1.0 with a different set of patches for another target, there is no
guarantee that the supposedly target-independent libstdc++ headers are
in fact the same -- yet the default is to put them in the same directory.

As far as I can tell, the only benefit of the libstdc++ default for
cross-compilation is that you can save a bit of disk space when
installing multiple targets in the same prefix.  But, the disk space
saved is tiny relative to the overall installation, and if the headers
are not in fact identical, then you will have corrupted the installation
of at least one target.

-- 
Mark Mitchell
CodeSourcery
mark@codesourcery.com
(650) 331-3385 x713