Type Alias core::num::NonZeroU128
1.28.0 · source · pub type NonZeroU128 = NonZero<u128>;Expand description
An integer that is known not to equal zero.
This enables some memory layout optimization.
For example, Option<NonZeroU128> is the same size as u128:
use std::mem::size_of;
assert_eq!(size_of::<Option<core::num::NonZeroU128>>(), size_of::<u128>());Run§Layout
NonZeroU128 is guaranteed to have the same layout and bit validity as u128
with the exception that 0 is not a valid instance.
Option<NonZeroU128> is guaranteed to be compatible with u128,
including in FFI.
Thanks to the null pointer optimization,
NonZeroU128 and Option<NonZeroU128>
are guaranteed to have the same size and alignment:
use std::num::NonZeroU128;
assert_eq!(size_of::<NonZeroU128>(), size_of::<Option<NonZeroU128>>());
assert_eq!(align_of::<NonZeroU128>(), align_of::<Option<NonZeroU128>>());RunAliased Type§
struct NonZeroU128(/* private fields */);