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 option to optval.
- Sets a single instance of option to optval.
- Resets (all instances) of option to their default value.
- Resets a single instance of option to its default value.
optstr is case insensitive and
option,
instance identifier and
optval 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
option,
instance identifier and
optval.