ILOG2(3) NetBSD Library Functions Manual ILOG2(3)
ilog2 -- integer logarithm
#include <sys/bitops.h> size ilog2(size x);
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.
A value -1 is returned on error.
bitops(3), ilogb(3), log2(3), imax(9), powerof2(9)
The ilog2() macro first appeared in NetBSD 5.0. NetBSD 6.0 May 10, 2011 NetBSD 6.0
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