WasUndoc 
                                                   
This API service was first documented by Microsoft
in DOS 5.0, but is supported by earlier versions.

The  WasUndoc  flag is irrelevant with regard to
programming considerations; only the supported
version number is important.
                                                   
TECH Help! flags these services only to bring them
to your attention.  They are often useful and might
otherwise be overlooked as a programming resource.

WasUndoc