stdc_count_ones3
Count the ones in an integer
Usage
Standard C Library (libc, -lc)
#include <stdbit.h>
unsigned int
stdc_count_ones_uc(unsigned char value);
unsigned int
stdc_count_ones_us(unsigned short value);
unsigned int
stdc_count_ones_ui(unsigned int value);
unsigned int
stdc_count_ones_ul(unsigned long value);
unsigned int
stdc_count_ones_ull(unsigned long long value);
unsigned int
stdc_count_ones(value);
Overview
The stdc_count_ones_type() family of functions returns the number of bits set to 1 in value, where value is of type unsigned char, unsigned short, unsigned int, unsigned long, or unsigned long long for type being uc, us, ui, ul, or ull respectively. This is also known as the “population count” (popcount) or “Hamming weight” operation. The stdc_count_ones(value) type-generic macro picks the appropriate stdc_count_ones_type() function based on the type of value.
Return values
Returns the number of bits set to 1 in value.
Releases
2 releases since FreeBSD 15.1-RELEASE; the text changed 1 time.