POPCOUNT(3) Library Functions Manual POPCOUNT(3)
popcount, popcountl, popcountll, popcount32, popcount64 -- count number
of bits set in a bit string
Standard C Library (libc, -lc)
popcount(unsigned int value);
popcountl(unsigned long value);
popcountll(unsigned long long value);
The popcount functions returns the number of bits set in value.
The popcount(), popcountl(), popcountll(), popcount32(), and popcount64()
functions appeared in NetBSD 6.0.
NetBSD 6.1.5 August 22, 2011 NetBSD 6.1.5