Re: Unknown PowerPC Exception instead of callback from a framework in a CFM project (CFNetwork)
Re: Unknown PowerPC Exception instead of callback from a framework in a CFM project (CFNetwork)
- Subject: Re: Unknown PowerPC Exception instead of callback from a framework in a CFM project (CFNetwork)
- From: Quinn <email@hidden>
- Date: Thu, 3 Apr 2003 10:13:22 +0100
At 11:59 -0500 2/4/03, Francois Boissonneault wrote:
Now I might be wrong again, but I think it has difficulties to find
the callback - since I'm using a kind of "wrapper" to get all the
pointers to functions with the bundle thing.
CFM functions pointers are pointers to TVectors. Mach-O function
pointers are pointers to the actual code. Passing function pointers
directly between architectures causes lots of problems. The
solutions are as follows:
o If you have a Mach-O function pointer that you want to pass to CFM,
you can simply create a dummy TVector (first word contains the Mach-O
function pointer, second word contains NULL), and pass the address of
that.
o If you have a CFM function pointer that you want to pass to Mach-O,
you must create a crazy trampoline structure that recovers the CFM
TOC register from thin air. There's code for doing this in the "CFM
MachO CFM" sample on our web site.
<
http://developer.apple.com/samplecode/Sample_Code/Runtime_Architecture/CFM_MachO_CFM.htm>
Note that, if you're using a bundle, you can call
CFBundleGetFunctionPointerForName and it will automatically do the
right thing, depending on the runtime of the caller and the runtime
of the bundle. This is why your CFM -> Mach-O glue works for calling
Mach-O functions from CFM. However, there's no equivalent mechanism
for wrappers arbitrary function pointers for use by Mach-O.
S+E
--
Quinn "The Eskimo!" <
http://www.apple.com/developer/>
Apple Developer Technical Support * Networking, Communications, Hardware
_______________________________________________
macnetworkprog mailing list | email@hidden
Help/Unsubscribe/Archives:
http://www.lists.apple.com/mailman/listinfo/macnetworkprog
Do not post admin requests to the list. They will be ignored.