
gcd(+Number1, +Number2, -Result)

   Unifies Results with the Greatest Common Divisor of Number1 and Number2

Arguments
   Number1             Integer.
   Number2             Integer.
   Result              A variable or integer.

Type
   Arithmetic

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

    Result is gcd(Number1, Number2)

    which should be preferred for portability.

   The Greatest Common Divisor operation is only defined on integer arguments.

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




Modes and Determinism
   gcd(+, +, -) is det

Exceptions
     4 --- Number1 or Number2 is not instantiated (non-coroutining mode    only).
     5 --- Result is a number but not an integer.
     5 --- Number1 or Number2 is a number but not an integer.
    24 --- Number1 or Number2 is not of a numeric type.
    24 --- Result is neither a number nor a variable.

Examples
   
Success:
      gcd(9, 15, 3).
      gcd(-9, 15, 3).
      gcd(2358352782,97895234896224,X).  ( gives X = 6 )

Error:
      gcd(A, 2, 6).             (Error 4).
      gcd(1, 2, 3.0).           (Error 5).
      gcd(1.0, 2, 3.0).         (Error 5).
      gcd(4 + 2, 2, 12).        (Error 24).


See Also
   lcm / 3, is / 2
