SetIconCacheProc
SetIconCacheProc Set the procedure associated with an icon cache
#include <Icons.h> Finder Interface
OSErr SetIconCacheProc (theCache, theProc );
Handle theCache ; handle to icon cache
Ptr theProc ; ProcPtr for icon cache
returns Error Code; 0 = no error
SetIconCacheProc sets the ProcPtr value associated with thetheCache to
theProc.

Notes: SetIconCacheProc takes a ProcPtr parameter, theProc The ProcPtr
should have the following format:
Handle GetAnIcon (ResType theType, Ptr yourDataPtr);
This function should return either the icon data to be used to draw or nil to
signify that this entry in the icon cache does not exist. See
Drawing Icons with System 7 for more on icon caches.
This routine is not currently documented in MPW header files (hence, it is
not in any THINK C or THINK Pascal header file either). The information
given above comes from Macintosh Technical Note #306. This tech. note
also gives the inline glue for the call as follows:
pascal OSErr SetIconCacheProc (Handle theCache, Ptr yourDataPtr)
= {0x303C, 0x041C, 0xABC9};