ILOG2(3) BSD Library Functions Manual ILOG2(3)
NAME
ilog2 -- integer logarithm
SYNOPSIS
#include <sys/bitops.h>
size
ilog2(size x);
DESCRIPTION
The ilog2() macro returns an integer (binary) logarithm of x. It is the logarithm for base 2; the binary logarithm of x is the power to
which the number 2 must be raised to obtain the value x.
The type of the input parameter should be either uint32_t or uint64_t.
ERRORS
A value -1 is returned on error.
SEE ALSO
bitops(3), ilogb(3), log2(3), imax(9), powerof2(9)
HISTORY
The ilog2() macro first appeared in NetBSD 5.0.
BSD
May 10, 2011 BSD
