GCLRWK - clears a GKS workstation

       To use GKS routines, load the NCAR GKS-0A library ncarg_gks.

       #include <ncarg/gks.h>

       void gclear_ws(Gint ws_id, Gctrl_flag  ctrl_flag);

       Copyright (C) 1987-2009
       University Corporation for Atmospheric Research
       The use of this Software is governed by a License Agreement.

UNIX                                               March 1993                                     GCLRWK(3NCARG)

       WKID        (Integer, Input) - A number identifying the workstation to be cleared.  WKID must be the same
                   as that used in some previous GOPWK call.

       COFL        (Integer, Input) - Clear the workstation display surface. Options are:

                   0      Check  to  see  if  the  display surface is empty. If so, do not issue a clear surface
                          command.

                   1      Issue a clear surface command whether the surface has been written to or not.

       GCLRWK - clears a GKS workstation

       Online: gopwk, gacwk, gdawk, gclwk, gclear_ws

       Hardcopy: User's Guide for NCAR GKS-0A Graphics; NCAR Graphics Fundamentals, UNIX Version

       CALL GCLRWK (WKID, COFL)

       For workstations of type "1" (CGM), GCLRWK is interpreted as a picture termination in CGM generation.  If
       COFL  =  0  and no output primitives have been written in the current picture, then a call to GCLRWK is a
       "do nothing"; otherwise, it generates an END PICTURE element  (as  well  as  other  picture  initializing
       elements). If COFL = 1, then a call to GCLRWK generates an END PICTURE.

       For  workstations of types "7" or "8" (see the man page for GOPWK for a description of workstation types)
       clear workstations erases all primitives that appear on the screen.

       For all other workstation types, clear workstation simply updates the workstation.