Tribblix: manual page: stdc_bit

STDC_BIT_CEIL(9F) Kernel Functions for Drivers STDC_BIT_CEIL(9F)

NAME

stdc_bit_ceil, stdc_bit_ceil_uc, stdc_bit_ceil_us, stdc_bit_ceil_ui,
stdc_bit_ceil_ul, stdc_bit_ceil_ull - find smallest power of 2 not less
than value

SYNOPSIS

#include <sys/stdbit.h>

generic_value_type
stdc_bit_ceil(generic_value_type value);

unsigned char
stdc_bit_ceil_uc(unsigned char value);

unsigned short
stdc_bit_ceil_us(unsigned short value);

unsigned int
stdc_bit_ceil_ui(unsigned int value);

unsigned long
stdc_bit_ceil_ul(unsigned long value);

unsigned long long
stdc_bit_ceil_ull(unsigned long long value);

DESCRIPTION

The stdc_bit_ceil() family of functions finds the smallest power of 2
that is not less than value. If the resulting value would not fit in
the type, then 0 is returned. For example, if one were to use
UINT8_MAX with stdc_bit_ceil_uc() the next power of two would be 0x100,
which is larger than would fit in an 8-bit unsigned char, resulting in
0.

The stdc_bit_ceil() 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_bit_ceil() family returns the smallest power
of 2 that is not less than value. These functions cannot fail.

INTERFACE STABILITY