pub type NonZeroI32 = NonZero<i32>;
Expand description
An i32
that is known not to equal zero.
This enables some memory layout optimization.
For example, Option<NonZeroI32>
is the same size as i32
:
§Layout
NonZeroI32
is guaranteed to have the same layout and bit validity as i32
with the exception that 0
is not a valid instance.
Option<NonZeroI32>
is guaranteed to be compatible with i32
,
including in FFI.
Thanks to the null pointer optimization,
NonZeroI32
and Option<NonZeroI32>
are guaranteed to have the same size and alignment:
use std::num::NonZeroI32;
assert_eq!(size_of::<NonZeroI32>(), size_of::<Option<NonZeroI32>>());
assert_eq!(align_of::<NonZeroI32>(), align_of::<Option<NonZeroI32>>());
§Compile-time creation
Since both Option::unwrap()
and Option::expect()
are const
, it is possible to
define a new
NonZeroI32
at compile time via:
Aliased Type§
pub struct NonZeroI32(/* private fields */);