Type Alias serde::lib::num::NonZeroUsize

1.28.0 · source ·
pub type NonZeroUsize = NonZero<usize>;
Expand description

An integer that is known not to equal zero.

This enables some memory layout optimization. For example, Option<NonZeroUsize> is the same size as usize:

use std::mem::size_of;
assert_eq!(size_of::<Option<core::num::NonZeroUsize>>(), size_of::<usize>());


NonZeroUsize is guaranteed to have the same layout and bit validity as usize with the exception that 0 is not a valid instance. Option<NonZeroUsize> is guaranteed to be compatible with usize, including in FFI.

Thanks to the null pointer optimization, NonZeroUsize and Option<NonZeroUsize> are guaranteed to have the same size and alignment:

use std::num::NonZeroUsize;

assert_eq!(size_of::<NonZeroUsize>(), size_of::<Option<NonZeroUsize>>());
assert_eq!(align_of::<NonZeroUsize>(), align_of::<Option<NonZeroUsize>>());

Aliased Type§

struct NonZeroUsize(usize);


§0: usize
🔬This is a nightly-only experimental API. (generic_nonzero)

Trait Implementations§


impl<'de> Deserialize<'de> for NonZeroUsize


fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer. Read more

impl Serialize for NonZeroUsize


fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where S: Serializer,

Serialize this value into the given Serde serializer. Read more