[ Arithmetic | Reference Manual | Alphabetic Index ]

setbit(+Number, +Index, -Result)

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


Set the Index'th bit in Number giving Result. The least significant bit has index zero. Two's complement representation is assumed. This predicate is used by the ECLiPSe compiler to expand evaluable arithmetic expressions. So the call to setbit(Number, Index, Result) is equivalent to
    Result is setbit(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.


    Result is setbit(0, 3).		% gives Result = 8
    Result is setbit(1, 8).		% gives Result = 257
    Result is setbit(setbit(0,3),5).	% gives Result = 40

See Also

is / 2, clrbit / 3, getbit / 3