# Function std::intrinsics::unlikely

const: unstable · source ·

    pub extern "rust-intrinsic" fn unlikely(b: bool) -> bool

🔬This is a nightly-only experimental API. (`core_intrinsics`)
Expand description

Hints to the compiler that branch condition is likely to be false. Returns the value passed to it.

Any use other than with `if` statements will probably not have an effect.

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.

This intrinsic does not have a stable counterpart.