Obtains a group of strings from the environment KPG1_GTGRP
The user specifies the strings by supplying a GRP group expression for the parameter value. If the
final character in the supplied string is the group " flag character" (a minus sign by default), then the
user is re-prompted for another group expression, and the strings specified by the second group
expression are appended to the returned group. This continues until a group expression is supplied
which does not end with the continuation character, or a null value is supplied (which is
annulled).
Normally, the " current value" for the parameter on exit would be the final group expression. If more
than one group expression was supplied, then this will not represent the entire group. For this
reason, this routine concatenates all the group expressions supplied, and stores the total
group expression as the parameter value before exiting. Since a new value is stored for the
parameter, the parameter should ne be given an access mode of READ in the interface
file.
If a null value is supplied the first time the parameter value is obtained, then the PAR__NULL status is returned, and SIZE is returned as zero (a valid GRP identifier is still returned however). If a null value is supplied on a subsequent access to the parameter, then the PAR__NULL status is annulled, and the group is returned containing any values obtained earlier.