All GNS routines use the so called inherited status strategy
(see SUN/104), which means
that if the STATUS argument is not set to the value SAI__OK
(equals zero) on entry the routine will exit without performing any action. If
an error occurs during the execution of a routine, STATUS will be set to
one of the values defined in the FORTRAN include file GNS_ERR.
GNS [2.5exrkstation