pub type NonZeroU8 = NonZero<u8>;Expand description
An integer that is known not to equal zero.
This enables some memory layout optimization.
For example, Option<NonZeroU8> is the same size as u8:
use std::mem::size_of;
assert_eq!(size_of::<Option<core::num::NonZeroU8>>(), size_of::<u8>());Run§Layout
NonZeroU8 is guaranteed to have the same layout and bit validity as u8
with the exception that 0 is not a valid instance.
Option<NonZeroU8> is guaranteed to be compatible with u8,
including in FFI.
Thanks to the null pointer optimization,
NonZeroU8 and Option<NonZeroU8>
are guaranteed to have the same size and alignment:
use std::num::NonZeroU8;
assert_eq!(size_of::<NonZeroU8>(), size_of::<Option<NonZeroU8>>());
assert_eq!(align_of::<NonZeroU8>(), align_of::<Option<NonZeroU8>>());RunAliased Type§
struct NonZeroU8(/* private fields */);