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