SUBROUTINE CTRLCEN
C-----------------------------------------------------------------------
C CTRLCEN and CTRLCAST are Fortran routines that let you set up a
C Control-C handling facility.
C
C Call CTRLCEN to enable the next control-C typed on the keyboard
C to activate the CTRLCAST AST handler.  CTRLCAST sets the common
C flag CCFLAG in common /CONTROLC/, which may be tested by your
C program.
C
C You must call CTRLCEN each time you want to allow a control-C input.
C
C These programs do not affect the handling of control-Y.
C The logical name "TT" is translated to find your terminal. If
C TT is not a terminal, a warning message will be written on
C SYS$OUTPUT and the AST will not be set up.
C
C  7-Dec-1981 - M. Ewing.
C  3-Jan-1985 - revised for VAX/VMS Fortran V4.0 [TJP].
C  4-Apr-1988 - dummy version for Convex [TJP].
C-----------------------------------------------------------------------
      END