From: Vladimir Prus (ghost_at_[hidden])
Date: 2006-10-11 04:18:23
On Tuesday 10 October 2006 17:59, David Abrahams wrote:
> error: gcc initialization: parameter 'version' inconsistent
> error: no value was specified in earlier initialization
> error: an explicit value is specified now
>
> We've discussed this problem before. Any site administrator who
> invokes "using gcc ;" in site-config.jam prevents users from
> initializing gcc with a version. Any site administrator who adds a
> new "using" invocation to site-config.jam (even a versioned one)
> potentially breaks the user-config.jam of any users.
>
> The only safe thing for everyone concerned is to never invoke "using"
> without a version identifier:
>
> using gcc : default ;
>
> but after all, isn't that just redundant? The system could simply do
> that for me. And finally, it won't work for the Python toolset, for
> example, which expects that 2nd argument to be a real, meaningful
> toolset version.
>
> Why do we still have this requirement that "using" be invoked
> consistently?
I think there were technical reasons. Specifically, some flag settings depends
on toolset setting and so must be a condition, so that they are not used for
other toolset.
If we have
flags gcc.compile WHATEVER <toolset>gcc : ......
flags gcc.compile WHATEVER <toolset>gcc,<toolset:gcc-version>3.4 : ......
both flag settings will be used, which means that default-initialize gcc will
add his settings to all version-initiialized gccs. Now, we have a mechanism
to say:
flags gcc.compile WHATEVER
<toolset>gcc,<toolset:gcc-version> : ......
flags gcc.compile WHATEVER
<toolset>gcc,<toolset:gcc-version>3.4 : ......
So removing the consistency requirement should be possible. I'm a bit worried
about "gcc" and "gcc-4.1" being names of exactly the same compiler, but
perhaps that's fine.
Code-wise, all that's needed is change common.check-init-parameters to avoid
the check, use the value-less syntax for features that are not specified.
As usual, help in doing that would be appreciated. If you don't have the time,
can you file an issue?
Thanks,
Volodya