std::intrinsics

Function cttz

Source
pub const fn cttz<T>(_x: T) -> u32
where T: Copy,
🔬This is a nightly-only experimental API. (core_intrinsics)
Expand description

Returns the number of trailing unset bits (zeroes) in an integer type T.

Note that, unlike most intrinsics, this is safe to call; it does not require an unsafe block. Therefore, implementations must not require the user to uphold any safety invariants.

The stabilized versions of this intrinsic are available on the integer primitives via the trailing_zeros method. For example, u32::trailing_zeros

§Examples

#![feature(core_intrinsics)]

use std::intrinsics::cttz;

let x = 0b0011_1000_u8;
let num_trailing = cttz(x);
assert_eq!(num_trailing, 3);

An x with value 0 will return the bit width of T:

#![feature(core_intrinsics)]

use std::intrinsics::cttz;

let x = 0u16;
let num_trailing = cttz(x);
assert_eq!(num_trailing, 16);