Darwin Version

[Brandon Allbery]

I should note that that's just an example; libSystem has only changed that
way once, I think. But the same applies to other Apple-only frameworks,
which change more often and more radically. Apple also has no qualms about
removing old frameworks they don't care about any more, in which case your
old 10.5 programs relying on those frameworks *will* stop working (I think
they did that with QuickTime?).

Basically, if Apple cared they could make this stuff work. But they don't,
so migration becomes a major hassle.

On Fri, Oct 2, 2015 at 9:52 AM, Brandon Allbery <allbery.b at gmail.com> wrote:

> On Fri, Oct 2, 2015 at 9:31 AM, Bachsau <web at bachsau.name> wrote:
>
>> Maybe. Seems like I'm just not getting what is technically causing these
>> problems. When libraries change, and it breaks a particular application,
>> why can't I recompile just that? And why would the build of a newly
>> installed port fail, just because there are other ports installed that were
>> compiled against older system libraries?
>
>
> Dependencies. Port X compiles against new libSystem, depends on port Y
> that was linked against old libSystem, link fails because it tries to bring
> in both versions and they conflict. (Keeping around old libSystem versions
> is how you can still run applications built for 10.5 on 10.10/10.11.)
>
> This doesn't happen on Linux because glibc is obsessive about maintaining
> backward compatibility interfaces, so the older program links against the
> current glibc and uses compatibility interfaces from it; this works even
> for libraries. Apple doesn't care about backward compatibility enough to do
> things that way.
>
> --
> brandon s allbery kf8nh                               sine nomine
> associates
> allbery.b at gmail.com
> ballbery at sinenomine.net
> unix, openafs, kerberos, infrastructure, xmonad
> http://sinenomine.net
>



-- 
brandon s allbery kf8nh                               sine nomine associates
allbery.b at gmail.com                                  ballbery at sinenomine.net
unix, openafs, kerberos, infrastructure, xmonad        http://sinenomine.net
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