It is very important to set ioNamePtr when making PB calls, even if you don't want those calls to return a name. Whenever Inside Macintosh indicates that ioNamePtr is either required for input or returns something, you must set ioNamePtr to either nil (if you aren't using a name) or to point to storage for a Str255.
If you don't explicitly set ioNamePtr, strange and unusual crashes may occur, depending on the machine/configuration your code is run on.
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