On entry: a string identifying the option, its value and, where required, the instance identifier.
- Resets all options to their default values.
- Sets (all instances) of to .
- Sets a single instance of to .
- Resets (all instances) of to their default value.
- Resets a single instance of to its default value.
optstr is case insensitive and
,
instance identifier and
may consist of one or more tokens separated by white space.
See the documentation of the individual functions in the
G22 Chapter Introduction for details of valid values for
,
instance identifier and
.