std::intrinsics

Function compare_bytes

Source
pub const unsafe extern "rust-intrinsic" fn compare_bytes(
    left: *const u8,
    right: *const u8,
    bytes: usize,
) -> i32
🔬This is a nightly-only experimental API. (core_intrinsics)
Expand description

Lexicographically compare [left, left + bytes) and [right, right + bytes) as unsigned bytes, returning negative if left is less, zero if all the bytes match, or positive if left is greater.

This underlies things like <[u8]>::cmp, and will usually lower to memcmp.

§Safety

left and right must each be valid for reads of bytes bytes.

Note that this applies to the whole range, not just until the first byte that differs. That allows optimizations that can read in large chunks.