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

[Thomas Sachau]

Alexis Ballier schrieb:
> On Sun, 03 Mar 2013 17:27:50 +0100
> Thomas Sachau <tommy@g.o> wrote:
>
>> Alexis Ballier schrieb:
>>> On Sun, 03 Mar 2013 16:47:43 +0100
>>> Thomas Sachau <tommy@g.o> wrote:
>>>
>>>> Alexis Ballier schrieb:
>>>>> On Sun, 03 Mar 2013 14:02:58 +0100
>>>>> Thomas Sachau <tommy@g.o> 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.
>

The wrapper is already in a seperate package [1], the currently active
and tested version (1.0) is in bash, also there is a (currently masked)
version 2.0 written by binki in C doing the same natively. So you even
have a choice in what to use. :-)

[1]:
http://git.overlays.gentoo.org/gitweb/?p=proj/multilib-portage.git;a=tree;f=sys-apps/abi-wrapper

-- 

Thomas Sachau
Gentoo Linux Developer