NAME
stdc_leading_zeros – find the number of leading zeros in an integer
SYNOPSIS
Standard C Library (libc, -lc)
#include <stdbit.h>
unsigned int
stdc_leading_zeros_uc(unsigned char value);
unsigned int
stdc_leading_zeros_us(unsigned short value);
unsigned int
stdc_leading_zeros_ui(unsigned int value);
unsigned int
stdc_leading_zeros_ul(unsigned long value);
unsigned int
stdc_leading_zeros_ull(unsigned long long value);
unsigned int
stdc_leading_zeros(value);
DESCRIPTION
The stdc_leading_zeros_type() family of functions returns the number of leading zeros 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. The stdc_leading_zeros(value) type-generic macro picks the appropriate stdc_leading_zeros_type() function based on the type of value.
RETURN VALUES
Returns the number of leading zeros in value. If value is all zeros, the total number of bits in the type of value is returned.
SEE ALSO
stdbit(3), stdc_first_leading_one(3), stdc_leading_ones(3), stdc_trailing_zeros(3)
STANDARDS
The stdc_leading_zeros_type() family of functions and the stdc_leading_zeros() type-generic macro conform to ISO/IEC 9899:2024 (“ISO C23”).
HISTORY
The stdc_leading_zeros_type() family of functions and the stdc_leading_zeros() type-generic macro were added in FreeBSD 15.1.
AUTHORS
Robert Clausecker ⟨[email protected]⟩