Tribblix: manual page: stdc_trailing_zeros

STDC_TRAILING_ZEROS(9F) Kernel Functions for Drivers

NAME

stdc_trailing_zeros, stdc_trailing_zeros_uc, stdc_trailing_zeros_us,
stdc_trailing_zeros_ui, stdc_trailing_zeros_ul, stdc_trailing_zeros_ull
- count consecutive trailing zero bits

SYNOPSIS

#include <sys/stdbit.h>

unsigned int
stdc_trailing_zeros(generic_value_type value);

unsigned int
stdc_trailing_zeros_uc(unsigned char value);

unsigned int
stdc_trailing_zeros_us(unsigned short value);

unsigned int
stdc_trailing_zeros_ui(unsigned int value);

unsigned int
stdc_trailing_zeros_ul(unsigned long value);

unsigned int
stdc_trailing_zeros_ull(unsigned long long value);

DESCRIPTION

The stdc_trailing_zeros() family of functions counts the number of
consecutive zero bits present in value starting at the least
significant bit.

The stdc_trailing_zeros() function is generic and will operate on all
8, 16, 32, and 64-bit unsigned integers; however, it is only available
in C23. The other functions all operate on a specific integer type,
but otherwise behave the same and are available regardless of the C
language version.

CONTEXT

These functions may be called from user, kernel, or interrupt context.

RETURN VALUES

The functions in the stdc_trailing_zeros() family always return the
number of trailing zeros found in value. These functions cannot fail.

INTERFACE STABILITY