[R-SIG-Mac]OS X and OS 9

[Ken Beath]

One point that needs to be clarified is that Carbon itself is not a 
problem. Apple originally saw Carbon as a transition technology but 
that seems to have ended after Adobe, Microsoft et al told them it 
that they wouldn't convert their code to run using anything else. Now 
it is just one option for constructing applications.

The important factor is Mach-O vs CFM. These determine how a 
executable is constructed and how it is loaded into memory and runs. 
CFM is the method used on PowerPC prior to MacOS X.  For MacOS X you 
can compile carbon to either Mach-O or CFM. Only the CFM runs on 
earlier OS. The Mach-O apps allow a lot more. You can access some 
newer features of Carbon and use Cocoa and Unix routines.  You can 
for example use Carbon for the interface, Unix for the file calls and 
whatever bits of Cocoa appeal.

In CodeWarrior the IDE does most of the work of changing a CFM app to 
Mach-O. Only apps that do things like loading in code and other 
similar things or use CFM libraries need changes. (I should add that 
I haven't tried this myself)