SET (CLIENT_MESSAGE)

  Specifies the program or learn sequence DECTPU should execute whenever it
  receives a client message from another DECwindows application.

  Syntax

     SET (CLIENT_MESSAGE, SCREEN [, {program_source | NONE}])

  Parameters

     SCREEN               A keyword used for compatibility with future
                          versions of DECTPU.

     program_source       A string, buffer, range, learn sequence, or
                          program specifying the client message routine.  If
                          you do not specify this parameter, DECTPU deletes
                          the current client message routine; thereafter,
                          your application is not informed when DECTPU
                          receives a client message from DECwindows.

     NONE                 A keyword instructing DECTPU to delete the current
                          client message routine.