Type Alias std::num::NonZeroU64
1.28.0 · source · pub type NonZeroU64 = NonZero<u64>;Expand description
An integer that is known not to equal zero.
This enables some memory layout optimization.
For example, Option<NonZeroU64> is the same size as u64:
use std::mem::size_of;
assert_eq!(size_of::<Option<core::num::NonZeroU64>>(), size_of::<u64>());Run§Layout
NonZeroU64 is guaranteed to have the same layout and bit validity as u64
with the exception that 0 is not a valid instance.
Option<NonZeroU64> is guaranteed to be compatible with u64,
including in FFI.
Thanks to the null pointer optimization,
NonZeroU64 and Option<NonZeroU64>
are guaranteed to have the same size and alignment:
use std::num::NonZeroU64;
assert_eq!(size_of::<NonZeroU64>(), size_of::<Option<NonZeroU64>>());
assert_eq!(align_of::<NonZeroU64>(), align_of::<Option<NonZeroU64>>());RunAliased Type§
struct NonZeroU64(/* private fields */);