Function std::intrinsics::ctlz
const: 1.40.0 · source · pub const extern "rust-intrinsic" fn ctlz<T>(x: T) -> Twhere
T: Copy,
🔬This is a nightly-only experimental API. (
core_intrinsics
)Expand description
Returns the number of leading 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 leading_zeros
method. For example,
u32::leading_zeros
§Examples
#![feature(core_intrinsics)]
use std::intrinsics::ctlz;
let x = 0b0001_1100_u8;
let num_leading = ctlz(x);
assert_eq!(num_leading, 3);
RunAn x
with value 0
will return the bit width of T
.
#![feature(core_intrinsics)]
use std::intrinsics::ctlz;
let x = 0u16;
let num_leading = ctlz(x);
assert_eq!(num_leading, 16);
Run