Q: I'm trying to port my 68K code to PPC. I have custom functions
defined for calling ModalDialog. Here's what my code looked like:
ModalDialog((ModalFilterProcPtr) MyFilter, &itemNum);
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The compiler complained that it cannot covert my custom function to type
RoutineDescriptor*, so I changed it by casting it to RoutineDescriptor:
ModalDialog((RoutineDescriptor*) MyFilter, &itemNum);
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There were no compile or link errors, but now, when I run the program, it
crashes with a type 3 error.
What's the correct way to implement this?
A: Create a UPP using NewRoutineDescriptor instead of casting to a UPP. In
Dialogs.h there is a macro for NewRoutineDescriptor called NewModalFilterProc.
Your code should look like this:
ModalFilterUPP myFilterUPP;
myFilterUPP = NewModalFilterProc(MyFilter);
ModalDialog(myFilterUPP, &itemNum);
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See Also
- See Using Universal Procedure Pointers in Inside Macintosh: PPC System
Software, page 2-21, for more information.
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