Obtain the names of a group of catalogues to be created from the environment CTG_CREAT
GRP__NOID on entry, then a new group is created and IGRP is returned holding the new group
identifier.
If IGRP0 holds a valid group identifier on entry, then the group identified by IGRP0 is
used as the basis for any modification element contained in the group expression obtained
from the environment. If IGRP0 holds an invalid identifier (such as GRP__NOID) on entry
then modification elements are included literally in the output group.
the basis token (an asterisk) is replaced by the file basename associated with the corresponding element of the basis group (the basis catalogue); else
if no directory specification is included in the group expression, the directory specification associated with the basis catalogue is used.
The supplied group will often be created by CTG_ASSOC, but groups created by hand
using GRP directly can also be used (i.e. without the supplemental groups created by CTG).
In this case, there are no defaults for directory path or file type, and the basis token
("") in
the group expression represents the full basis file specification supplied in IGRP0, not just the file
basename.
.TRUE.. Otherwise it is returned .FALSE.. Returned .FALSE.
if an error occurs. Any FITS extensions specified in the group expression are ignored.
If an error is reported the group is returned unaltered.
A null value (!) can be given for the parameter to indicate that no more catalogues are to be specified.
The corresponding error is annulled before returning unless no catalogues have been added to the
group.
If no file type is supplied in the group expression, then the first file type listed in
the current value of the CAT_FORMATS_OUT environment variable is used. If this is
"" then
the file type is copied from the corresponding input file if a modification element was used to specify
the output file name (if the catalogue was not specified by a modification element, the second file type
in CAT_FORMATS_OUT is used).
If the last character in the supplied group expression is a colon (:), a list of the catalogues represented
by the group expression (minus the colon) is displayed, but none are actually added to the group. The
user is then re-prompted for a new group expression.
The returned group has no associated groups holding supplemental information (unlike the group returned by CTG_ASSOC).