POPCOUNT(3) | Library Functions Manual | POPCOUNT(3)

# NAME

`popcount`, `popcountl`, `popcountll`, `popcount32`, `popcount64` —
count number of bits set in a bit string

# LIBRARY

Standard C Library (libc, -lc)

# SYNOPSIS

`#include <strings.h>`

unsigned int
`popcount`(unsigned int value);

unsigned int
`popcountl`(unsigned long value);

unsigned int
`popcountll`(unsigned long long value);

`#include <stdint.h>`

unsigned int
`popcount32`(uint32_t value);

unsigned int
`popcount64`(uint64_t value);

# DESCRIPTION

The `popcount` functions return the number of bits set in value.

# SEE ALSO

ffs(3)

# HISTORY

The `popcount`(), `popcountl`(), `popcountll`(), `popcount32`(), and `popcount64`() functions appeared in NetBSD 6.0.

August 22, 2011 | NetBSD 9.3