Backwards binary compatibility in new OSX versions

[ardi]

What're the implications of the -isysroot and -mmacosx-version-min
flags? I've always used them together, but, can you use just one of
them? What happens if you use only one of them? What binary
compatibility do you achieve with each one?

This is the reason why I'm asking this:

I'm considering upgrading one of my machines to Mountain Lion (10.8)
as soon as it's released. However, I'm going to keep another one with
10.6.8.

Now the problem is that Apple, as usual, will include just 2 SDKs, so
in 10.8 you'll only have the 10.7 and 10.8 SDKs.

Do you think is there any way of sharing object code across 10.6 and
10.8? When developing, I tend to share object code across machines, in
order to avoid recompiling when I change my machine, but of course
this requires binary compatibility.

Until today, I've been sharing object code between 10.6 and 10.7 with
success, by using -isysroot /Developer/SDKs/MacOSX10.6.sdk -mmacosx-
version-min=10.6 when compiling on both machines.

But, now, if I upgrade to 10.8, I won't have the 10.6 SDK there, so I
won't be able to use -isysroot... so I wonder if I can get the same
binary compatibility with just -mmacosx-version-min=10.6

TIA

ardi

[Stefan Csomor]

Hi

>What're the implications of the -isysroot and -mmacosx-version-min
>flags? I've always used them together, but, can you use just one of
>them? What happens if you use only one of them? What binary
>compatibility do you achieve with each one?

isysroot = latest OS X Version your are benefitting from, because its
features will be used by wx when available


mmacosx-version-min = the minimum system usable for deployment

>But, now, if I upgrade to 10.8, I won't have the 10.6 SDK there, so I
>won't be able to use -isysroot... so I wonder if I can get the same
>binary compatibility with just -mmacosx-version-min=10.6

yes

Best,

Stefan