Are the three main compiler flavors supported by Xcode (gcc 4.0, 4.2, and llvm) binary-compatible with one another? What kind of gotchas and corner cases should I be aware of when bringing a multi-library project up to speed with the most recent Xcode tools?
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            Clang is ABI-compatible with code generated by gcc. Clang also includes experimental support for some newer Objective-C ABIs, but compiling for the newer ABI requires flags, and generated code can be mixed with GCC-generated code anyway.
                  mipadi
                   2010-09-09 14:47:11
                
              
                
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              A minor gotcha is that if you want to compile PowerPC code that will run on a G3, you must use GCC 4.0.
                  JWWalker
                   2010-09-09 16:45:55
                
              Thanks for the tip; we won't need to compile PPC unless Apple returns to it, but good to know in general.
                  fbrereto
                   2010-09-09 16:56:31