SET (GLOBAL_SELECT)

  Causes TPU to request ownership of the specified global selection
  property.  An optional fourth parameter allows the application to also
  relinquish a global selection.

  Syntax

     [integer := ] SET (GLOBAL_SELECT, SCREEN, {PRIMARY | SECONDARY
                       | selection_name}
                       [, {GLOBAL_SELECT_GRAB | GLOBAL_SELECT_UNGRAB])

  Parameters

     integer              Indicates whether the global selection ownership
                          request was granted.  1 if successful, 0
                          otherwise.

     PRIMARY              A keyword indicating that the layered application
                          is requesting ownership of the PRIMARY global
                          selection.

     SECONDARY            A keyword indicating that the layered application
                          is requesting is requesting ownership of the
                          SECONDARY global selection.

     selection_name       A string identifying the global selection that the
                          layered application wants to own.  You specify the
                          selection name as a string if the layered
                          application is requesting ownership of a selection
                          other than the PRIMARY or SECONDARY global
                          selection.

     GLOBAL_SELECT_GRAB    TPU to grab the selection specified in the
                          second parameter.  This is the default if you do
                          not specify the fourth parameter.

     GLOBAL_SELECT_UNGRAB A keyword telling TPU to relinquish the
                          selection specified in the second parameter.