Application-Defined Function

You can name the application-defined fallback handler anything you choose--the name is not significant. Here, the name MyUnicodeToTextFallbackProc is used for illustrative purposes. However, the parameters, the return type, and the calling convention are all important, since a pointer to the application-defined fallback handler function must be of type UnicodeToTextFallbackProcPtr as defined in UnicodeConverter.h.