ILOG2(3) | Library Functions Manual | ILOG2(3) |
ilog2
—
#include <sys/bitops.h>
int
ilog2
(size
x);
ilog2
() macro
returns the integer part of the base-2 logarithm of x;
that is,
floor
(log_2
(x));.
If n =
ilog2
(x), then
n is the largest integer such that
2**n
<=
x; in other words,
ilog2
() returns the largest integer to which 2 can be
raised to obtain a value at most x.
The type of the input parameter must be unsigned.
If x is a constant expression, then so is
ilog2
(x).
ilog2
() returns -1 when x is zero.
ilog2
() macro first appeared in
NetBSD 5.0.
November 5, 2021 | NetBSD 10.0 |