Type Alias std::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>());Run§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>>());RunAliased Type§
struct NonZeroIsize(/* private fields */);