# Function std::intrinsics::compare_bytes

const: unstable · source ·

    pub 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 `right` 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.