Consider this a sort of "tip-of-the-week" for everyone writing software for Palm OS 5 
(or earlier):

Don't use MemDeref -- use MemHandleLock and MemHandleUnlock instead.

MemDeref is a macro which assumes an understanding of a handle's representation and 
implementation. It bypasses the memory manager semaphore and low-level error checking 
routines, thus providing improved performance in time-sensitive applications. It was 
used by a number of our built-in PIM apps and sample code during early SDK releases, 
but was removed long ago in favor of more robust and supportable APIs.

While testing application compatibility with our new Palm OS 5, we've found that many 
3rd party developers are still using this macro today as an alternative to the 
MemHandleLock API. Unfortunately, MemDeref cannot be supported by our 68k emulation 
architecture, nor is it available in native ARM code, thus any application which uses 
it will fail (rather ungracefully...) when run under Palm OS 5. So, please update your 
software accordingly.

"This has been a public service announcement... we now return you to your regularly 
scheduled programming." :o)

Jim Schram
PalmSource Inc.
Partner Engineering

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