[ Arithmetic | Reference Manual | Alphabetic Index ]

getbit(+Number, +Index, -Result)

Result is the Index'th bit of Number.
Non-negative integer.
Output: integer.


Returns the Index'th bit of Number, assuming binary two's complement representation. The least significant bit has index zero. The result is either 0 or 1. This predicate is used by the ECLiPSe compiler to expand evaluable arithmetic expressions. So the call to getbit(Number, Index, Result) is equivalent to
    Result is getbit(Number, Index)
which should be preferred.

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

Modes and Determinism


(4) instantiation fault
Number or Index is not instantiated (non-coroutining mode only).
(5) type error
Number or Index is a number but not an integer.
(24) number expected
Number or Index is not of a numeric type.


    % 10 is binary 1010
    Result is getbit(10, 3).		% gives Result = 1.
    Result is getbit(10, 2).		% gives Result = 0.
    Result is getbit(10, 99).		% gives Result = 0.

See Also

is / 2, clrbit / 3, setbit / 3