Struct OnceLockCompat 

pub struct OnceLockCompat<T> { /* private fields */ }

A cache-invalidation wrapper with consistent semantics across std and no_std.

Feature	Backing type
std	std::sync::OnceLock<T>
no_std	once_cell::race::OnceBox<T>

Why not Clone?

Under std, OnceLock::clone copies the initialized value. Under no_std, OnceBox does not support value extraction, so a “clone” would silently produce an empty instance — a violation of the Clone contract. Clone is therefore not implemented on either configuration. If you need a fresh instance, call OnceLockCompat::new() explicitly.

Implementations

impl<T> OnceLockCompat<T>

pub const fn new() -> Self

Creates a new, empty OnceLockCompat.

pub fn get(&self) -> Option<&T>

Returns the value if already initialized, otherwise None.

pub fn get_or_init<F>(&self, f: F) -> &T

where F: FnOnce() -> T,

Returns the value if initialized, or initializes it with f.

If multiple threads race, each may execute f, but only one value is stored; the losers’ values are dropped immediately.

pub fn reset(&mut self)

Invalidates the cache so the next get_or_init recomputes the value.

no_std limitation

Under no_std the backing OnceBox does not support extracting its value, so the stored value is dropped on reset and cannot be recovered. If you need the value before invalidating, call get first.

Trait Implementations

impl<T: Debug> Debug for OnceLockCompat<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T> Default for OnceLockCompat<T>

fn default() -> Self

Returns the “default value” for a type.