The TRUNC function  converts  the  value  of  the  parameter  by
  truncating  the  fractional  part  of  the value and returns its
  integer equivalent.

  Syntax:

     TRUNC( x )

  The parameter 'x' must be  of  type  REAL,  SINGLE,  DOUBLE,  or
  QUADRUPLE.   The  value  of  'x'  must  not  be  too large to be
  represented by an integer.