.\"	$NetBSD: popcount.3,v 1.6 2016/07/14 18:21:31 abhinav Exp $
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.\" Copyright (c) 2009 The NetBSD Foundation, Inc.
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.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Joerg Sonnenberger.
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.Dd August 22, 2011
.Dt POPCOUNT 3
.Os
.Sh NAME
.Nm popcount ,
.Nm popcountl ,
.Nm popcountll ,
.Nm popcount32 ,
.Nm popcount64
.Nd count number of bits set in a bit string
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In strings.h
.Ft unsigned int
.Fn popcount "unsigned int value"
.Ft unsigned int
.Fn popcountl "unsigned long value"
.Ft unsigned int
.Fn popcountll "unsigned long long value"
.In stdint.h
.Ft unsigned int
.Fn popcount32 "uint32_t value"
.Ft unsigned int
.Fn popcount64 "uint64_t value"
.Sh DESCRIPTION
The
.Nm
functions return the number of bits set in
.Fa value .
.Sh SEE ALSO
.Xr ffs 3
.Sh HISTORY
The
.Fn popcount ,
.Fn popcountl ,
.Fn popcountll ,
.Fn popcount32 ,
and
.Fn popcount64
functions appeared in
.Nx 6.0 .