Struct MainThreadBound 

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

Wraps a !Send/!Sync value so it satisfies Send + Sync, while enforcing at runtime that it is only accessed on the thread that constructed it.

Safety model

The Send and Sync impls are unsafe: they are sound only because every access goes through Deref / DerefMut / into_inner, each of which asserts the caller is on the owning thread and panics otherwise, so the inner !Send value never actually crosses a thread boundary. If the wrapper is dropped on a non-owning thread the inner value is leaked rather than dropped, since running a !Send destructor off-thread would be undefined behavior.

The owner-thread check requires the std feature, which is on by default and must stay on for any build that can spawn a second thread. Disabling default features is reserved for genuinely single-threaded no_std builds, where there is no other thread to violate the confinement and the checks compile to no-ops; opting out on a threaded target silently removes the soundness net.

Implementations

impl<T> MainThreadBound<T>

pub fn new(value: T) -> Self

Bind value to the current (main) thread.

Recording the owning thread needs std; without it there is no thread to record and the binding is a plain wrapper, so that build gets a const constructor.

pub fn into_inner(self) -> T

Consume the wrapper and return the inner value, asserting the caller is on the owning thread.

Panics

Panics if called from a thread other than the one that constructed the value.

Trait Implementations

impl<T> Debug for MainThreadBound<T>

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

Formats the value using the given formatter.

impl<T> Deref for MainThreadBound<T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &T

Dereferences the value.

impl<T> DerefMut for MainThreadBound<T>

fn deref_mut(&mut self) -> &mut T

Mutably dereferences the value.

impl<T> Drop for MainThreadBound<T>

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.

impl<T> Send for MainThreadBound<T>

impl<T> Sync for MainThreadBound<T>