Struct tokio::io::unix::AsyncFdReadyGuard

#[must_use =
  "You must explicitly choose whether to clear the readiness state by calling a method on ReadyGuard"]pub struct AsyncFdReadyGuard<'a, T: AsRawFd> { /* fields omitted */ }

This is supported on crate feature net only.

Represents an IO-ready event detected on a particular file descriptor, which has not yet been acknowledged. This is a must_use structure to help ensure that you do not forget to explicitly clear (or not clear) the event.

Implementations

impl<'a, Inner: AsRawFd> AsyncFdReadyGuard<'a, Inner>

pub fn clear_ready(&mut self)

Indicates to tokio that the file descriptor is no longer ready. The internal readiness flag will be cleared, and tokio will wait for the next edge-triggered readiness notification from the OS.

It is critical that this function not be called unless your code actually observes that the file descriptor is not ready. Do not call it simply because, for example, a read succeeded; it should be called when a read is observed to block.

pub fn retain_ready(&mut self)

This function should be invoked when you intentionally want to keep the ready flag asserted.

While this function is itself a no-op, it satisfies the #[must_use] constraint on the AsyncFdReadyGuard type.

pub fn with_io<R>(&mut self, f: impl FnOnce() -> Result<R>) -> Result<R>

Performs the IO operation f; if f returns a WouldBlock error, the readiness state associated with this file descriptor is cleared.

This method helps ensure that the readiness state of the underlying file descriptor remains in sync with the tokio-side readiness state, by clearing the tokio-side state only when a WouldBlock condition occurs. It is the responsibility of the caller to ensure that f returns WouldBlock only if the file descriptor that originated this AsyncFdReadyGuard no longer expresses the readiness state that was queried to create this AsyncFdReadyGuard.

pub fn with_poll<R>(&mut self, f: impl FnOnce() -> Poll<R>) -> Poll<R>

Performs the IO operation f; if f returns Pending, the readiness state associated with this file descriptor is cleared.

This method helps ensure that the readiness state of the underlying file descriptor remains in sync with the tokio-side readiness state, by clearing the tokio-side state only when a Pending condition occurs. It is the responsibility of the caller to ensure that f returns Pending only if the file descriptor that originated this AsyncFdReadyGuard no longer expresses the readiness state that was queried to create this AsyncFdReadyGuard.

Trait Implementations

impl<'a, T: Debug + AsRawFd> Debug for AsyncFdReadyGuard<'a, T>

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

Formats the value using the given formatter.