Re: [gentoo-dev] Re: [RFC] multilib-build.eclass and restricting unsupported ABIs

[Alexis Ballier <aballier@gentoo.org>]

On Sun, 03 Mar 2013 17:27:50 +0100
Thomas Sachau <tommy@gentoo.org> wrote:

> Alexis Ballier schrieb:
> > On Sun, 03 Mar 2013 16:47:43 +0100
> > Thomas Sachau <tommy@gentoo.org> wrote:
> > 
> >> Alexis Ballier schrieb:
> >>> On Sun, 03 Mar 2013 14:02:58 +0100
> >>> Thomas Sachau <tommy@gentoo.org> wrote:
> >>>>
> >>>> Once the eclass has per-ABI header
> >>>
> >>> I think this is needed.
> >>>
> >>>> and binaries support,
> >>>
> >>> but here, could you enlighten me on its use cases ? I can't
> >>> imagine why having multi binaries support would be useful.
> >>>
> >>> Alexis.
> >>>
> >>
> >>
> >> At least some binaries do have abi-specific output, which is used
> >> by other applications. As a good example of this, have a look at
> >> qmake and qmake based build systems.
> > 
> > hmm, qmake doesnt seem to be the perfect example: how do you handle
> > this?
> > 
> > - install qmake-${abi}
> 
> ok
> 
> > - ln -s qmake-${DEFAULT_ABI} qmake
> 
> Just the same as with headers:
> 
> You dont symlink the headers for the default ABI, but instead a
> wrapper is placed, which does then call/include the real target, so
> in this case, qmake is then a symlink to the abiwrapper, which does
> execute the real abi-specific binary, depending on the current ABI.
> We can of course place this abiwrapper in every place, where it is
> needed instead of the symlink, but having one central and package
> provided wrapper instead is easier to maintain and update.
> 
> > - modify eqmake4 to call the right qmake when doing multilib?
> 
> not needed at all (with multilib-portage), since when any package
> calls qmake to get any abi-specific details, the abiwrapper executes
> the binary, that matches the ABI and you get the right details for
> your ABI.
> 

Indeed, nice idea. The wrapper can just call argv[0]-${ABI} or argv[0]
if ABI is unset or argv[0]-${ABI} does not exist.
Do you install this abiwrapper with multilib-portage? What would you
think about splitting it and adding such a package to the tree?

Alexis.