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Re: How to pass callback from mach-o to CFM

At 21:58 Uhr +0900 28.08.2003, Kiyoto Takeuchi wrote:
Also I could not understand acttually your code below.
void * NewCFMFromMachO(void * inMachoFunctionPtr)
{
void * result = NewPtr(8);
((void**)result)[0] = inMachoFunctionPtr;
((void**)result)[1] = result;
return result;
}
I guess your code simply slide [1] (second member of array) of marh-o
pointer.

Would you lindly explain outline of this method?
Do it require the understanding MACH-O Runtime architecture?
(I would like to know why the code work fine.)

Actually, it requires understanding the CFM runtime architecture. CFM uses "transition vectors" instead of real ProcPtrs, which are a data structure that contains the actual function pointer and some context information.

For MachO functions this isn't really needed, so what this code does is build a fake TVector with the MachO ProcPtr, so the CFM code can call it. Why he's passing the "result" pointer as the context pointer is beyond me, though. George Warner (Apple's CFM guy) told me to just pass zero there.
--
Cheers,
M. Uli Kusterer
------------------------------------------------------------
"The Witnesses of TeachText are everywhere..."
http://www.zathras.de
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References: 
 >Re: How to pass callback from mach-o to CFM (From: Kiyoto Takeuchi <email@hidden>)



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