The libref and data set name are displayed in two left-aligned
fields. If no SAS data set has been created in the current program,
SYSDSN returns eight blanks followed by _NULL_ followed by two more
blanks.
Note: The macro processor always
stores the value of SYSDSN in unquoted form. To quote the resolved
value of SYSDSN, use the %SUPERQ macro quoting function.