[ Arithmetic | The ECLiPSe Built-In Predicates | Reference Manual | Alphabetic Index ]

# *(+Number1, +Number2, -Result)

Evaluates the product Number1 * Number2 and unifies the resulting value with Result.

Number1
  A number.
Number2
  A number.
Result
  A variable or a number.

## Description

This predicate is used by the ECLiPSe compiler to expand evaluable arithmetic expressions. So the call to *(Number1, Number2, Result) is equivalent to

        Result is Number1 * Number2

which should be preferred for portability.

The result is of type breal if any of the arguments is a breal, else float if any of the arguments is a float, else rational if any of the arguments is a rational. Only when both arguments are integers is the result an integer.

In coroutining mode, if Number1 or Number2 are uninstantiated, the call to */3 is delayed until these variables are instantiated.

### Modes and Determinism

- *(+, +, -) is det

### Exceptions

(4) instantiation fault
  Number1 or Number2 is not instantiated (non-coroutining mode only).
(5) type error
  Result is of a different type than the evaluation result.
(24) number expected
  Number1 or Number2 is not of a numeric type.
(24) number expected
  Result is neither a number nor a variable.

## Examples

    Success:
          *(5, 2, 10).
          *(5, -2.0, -10.0).
    Fail:
          *(1, 2, 3).
          *(5, 2, 10.0).
          *(5, 2.0, 10).
    Error:
          *(A, 2, 6).             (Error 4).
          *(1, 2, 3.0).           (Error 5).
          *(4 + 2, 2, 12).        (Error 24).
          *(5, 2, r).             (Error 24).

## See Also

is / 2