We could probably merge Apple's and Sun's probes without too much
trouble. Apple simply extended function-entry to include the argcount in
addition to Sun's (filename, funcname, lineno) arguments. We could use
Apple's probe while retaining compatibility with Sun-oriented DTrace
scripts already in existence.

The two different function-returns are a bit of a problem. I recommend
starting with Sun's argument list because there are already a number of
quite useful scripts that use it in the DTraceToolkit. We could extend
Sun's argument list to add the *object pointer, but I don't actually
know of a use case. I haven't seen a script in the wild that uses it. It
seems like it would be tricky to write something in a DTrace script that
could make much use of it besides printing out the address. Maybe you
could navigate your way down to the type name, but that might be
unreliable. I suggest adding the *object pointer argument only if we can
devise a use case or if one of the Apple folks pop up with one. I don't
feel too bad making Apple devs modify a single character from their
internal scripts if they don't make them public.