The KEYED specifier asks whether a file is connected for keyed
access. It takes the following form:
KEYED = kyd
- kyd
- Is a character scalar memory reference that is assigned one of
the following values:
- 'YES': If keyed access is allowed for the file; the file must be indexed
- 'NO': If keyed access is not allowed
- 'UNKNOWN': If the processor is unable to determine whether keyed access
is allowed