OSErr MyWriteStatusToDTPWindow (gxStatusRecord aStatusRecord, gxDisplayRecord aDisplayRecord);should be corrected to read:
OSErr MyWriteStatusToDTPWindow (gxStatusRecord *aStatusRecord, gxDisplayRecord *aDisplayRecord);
A You're right. It's a typographical error that also appears in the new Toolbox Assistant electronic version of the documentation. The interface files are correct, however. As rule, it's best to check the interfaces if you need the declaration of a function or callback.