Undocumented 

This API service or structure is not documented by official

Microsoft sources.  Something may be undocumented for any

of several reasons:

  It is dangerous; you could lose data.

  It may change in future versions of DOS.

  It has no particular value; there are other ways...

In most cases, information contained in TECH Help! has been

gleaned from official Microsoft sources, such as a

Microsoft Knowledge Base on Compuserve or in trusted

publications such as Microsoft Systems Journal.  Some

information was obtained through trial-and-error testing.

In general, it's best to avoid using undocumented features.