Example

 $ IF F$GETSYI("CLUSTER_MEMBER") .EQS. "FALSE" THEN GOTO NOT_CLUSTER
 $ CONTEXT = ""
 $START:
 $   id = F$CSID (CONTEXT)
 $   IF id .EQS. "" THEN EXIT
 $   nodename = F$GETSYI ("NODENAME",,id)
 $   WRITE SYS$OUTPUT nodename
 $   GOTO start
 $NOT_CLUSTER:
 $ WRITE SYS$OUTPUT "Not a member of a cluster."
 $ EXIT

     This command procedure uses the F$CSID function to display
     a list of cluster system names. The assignment statement
     declares the symbol CONTEXT, which is used as the context-
     symbol argument for the F$CSID function. Because CONTEXT is
     equated to a null string, the F$CSID function will return the
     first cluster identification number in the cluster node list.

     If the F$CSID function returns a null value, then the command
     procedure either is at the end of the list, or is attempting
     this operation on a nonclustered node. The call to F$GETSYI
     checks whether the current node is a member of a cluster. The
     command procedure will exit on this condition.

     If the F$CSID function does not return a null value, then the
     command procedure uses the identification number as the third
     argument to the F$GETSYI function to obtain the name of the
     system. The name is then displayed using the WRITE command.