cDEC$ REAL

  Specifies the default real kind.  It takes the following form:

  cDEC$ REAL:{4 | 8 | 16}

    c        Is one of the following: C (or c), !, or *.

  The REAL directive specifies a size of 4 (KIND=4), 8 (KIND=8), or
  16 (KIND=16) bytes for default real numbers.

  When the REAL directive is effect, all default real variables are
  of the kind specified in the directive.  Only numbers specified or
  implied as REAL without KIND are affected.

  The REAL directive can only appear at the top of a program unit.  A
  program unit is a main program, an external subroutine or function,
  a module or a block data program unit.  The directive cannot appear
  between program units, or at the beginning of internal subprograms.
  It does not affect modules invoked with the USE statement in the
  program unit that contains it.

  For compatibility, !MS$REAL can be used in place of cDEC$ REAL.

  Consider the following:

  REAL r               ! a 4-byte REAL
  WRITE(*,*) KIND(r)
  CALL REAL8( )
  WRITE(*,*) KIND(r)   ! still a 4-byte REAL
                       !  not affected by setting in subroutine
  END
  SUBROUTINE REAL8( )
     !DEC$ REAL:8
     REAL s            ! an 8-byte REAL
     WRITE(*,*) KIND(s)
  END SUBROUTINE