
truncate(+Number, -Result)

   Unifies Result with the closest integer value between 0 and
Number, and of the same numeric type as Number.



Arguments
   Number              A number.
   Result              A variable or number.

Type
   Arithmetic

Description
   This predicate is used by the ECLiPSe compiler to expand evaluable
   arithmetic expressions.  So the call to truncate(Number, Result) is
   equivalent to

    Result is truncate(Number)

   which should be preferred for portability.

   This operation works on all numeric types. The result value is the
   closest integral value that lies between 0 and Number (rounding
   towards zero).

   The result type is the same as the argument type.  To convert the
   type to integer, use integer/2.

   In coroutining mode, if Number is uninstantiated, the call to truncate/2
   is delayed until this variable is instantiated.



Modes and Determinism
   truncate(+, -) is det

Exceptions
     4 --- Number is not instantiated (non-coroutining mode only).
     5 --- Result and Number are numbers of different types.
    24 --- Number is not of a numeric type.
    24 --- Result is neither a number nor a variable.

Examples
   
Success:
      X is truncate(1.8).	   (gives Result = 1.0)

      truncate(1.8, 1.0).
      truncate(-1.8, -1.0).
      truncate(5, 5).
      truncate(-6.4, Result).      (gives Result = -6.0)
Fail:
      truncate(1.0, 0.0).
Error:
      truncate(A, 6.0).                   (Error 4).
      truncate(0.5, 0).                   (Error 5).
      truncate(1, r).                     (Error 24).
      truncate(4 + 2.3, 6.0).             (Error 24).


See Also
   is / 2, floor / 2, ceiling / 2, round / 2, integer / 2, fix / 2
