Enum NotBlockable 

pub enum NotBlockable {
    CurrentThreadRuntime,
    BackgroundWorker,
}

A synchronous caller asked to block on an async operation from a thread where blocking cannot be made sound.

Both variants are the same defect seen through two executors: the calling thread is one the awaited future needs in order to make progress, so parking it parks the thing that would wake it. No blocking mechanism can fix that; the caller has to await the async operation instead of blocking on it.

Variants

CurrentThreadRuntime

A current-thread tokio runtime is entered on this thread. Parking it stops every task on that runtime, including whichever one holds the state the awaited future is waiting for.

BackgroundWorker

This thread is a background-facility worker — a callback band, the delayed-callback timer, or the scanOnce worker (crate::runtime::background). Each facility has a bounded worker set and every unit of work it carries is enqueued for those workers, so a parked worker is waiting for work only it could have run. On RTEMS spawn routes here, which makes the callback bands the one other place where parking is unsound.

Trait Implementations

impl Clone for NotBlockable

fn clone(&self) -> NotBlockable

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for NotBlockable

impl Debug for NotBlockable

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

Formats the value using the given formatter.

impl Display for NotBlockable

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

Formats the value using the given formatter.

impl Eq for NotBlockable

impl Error for NotBlockable

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

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

Provides type-based access to context intended for error reports.

impl PartialEq for NotBlockable

fn eq(&self, other: &NotBlockable) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for NotBlockable