pub struct Receiver<T> { /* private fields */ }
Implementations§
source§impl<T> Receiver<T>
impl<T> Receiver<T>
sourcepub fn try_recv(&self) -> Result<T, TryRecvError>
pub fn try_recv(&self) -> Result<T, TryRecvError>
Checks if there is a message in the channel without blocking. Returns:
Ok(message)
if there was a message in the channel.Err(Empty)
if theSender
is alive, but has not yet sent a message.Err(Disconnected)
if theSender
was dropped before sending anything or if the message has already been extracted by a previous receive call.
If a message is returned, the channel is disconnected and any subsequent receive operation using this receiver will return an error.
This method is completely lock-free and wait-free. The only thing it does is an atomic integer load of the channel state. And if there is a message in the channel it additionally performs one atomic integer store and copies the message from the heap to the stack for returning it.
sourcepub fn recv(self) -> Result<T, RecvError>
pub fn recv(self) -> Result<T, RecvError>
Attempts to wait for a message from the Sender
, returning an error if the channel is
disconnected.
This method will always block the current thread if there is no data available and it is
still possible for the message to be sent. Once the message is sent to the corresponding
Sender
, then this receiver will wake up and return that message.
If the corresponding Sender
has disconnected (been dropped), or it disconnects while
this call is blocking, this call will wake up and return Err
to indicate that the message
can never be received on this channel.
If a sent message has already been extracted from this channel this method will return an error.
§Panics
Panics if called after this receiver has been polled asynchronously.
sourcepub fn recv_ref(&self) -> Result<T, RecvError>
pub fn recv_ref(&self) -> Result<T, RecvError>
Attempts to wait for a message from the Sender
, returning an error if the channel is
disconnected. This is a non consuming version of Receiver::recv
, but with a bit
worse performance. Prefer [
Receiver::recv]
if your code allows consuming the receiver.
If a message is returned, the channel is disconnected and any subsequent receive operation using this receiver will return an error.
§Panics
Panics if called after this receiver has been polled asynchronously.
sourcepub fn recv_timeout(&self, timeout: Duration) -> Result<T, RecvTimeoutError>
pub fn recv_timeout(&self, timeout: Duration) -> Result<T, RecvTimeoutError>
Like Receiver::recv
, but will not block longer than timeout
. Returns:
Ok(message)
if there was a message in the channel before the timeout was reached.Err(Timeout)
if no message arrived on the channel before the timeout was reached.Err(Disconnected)
if the sender was dropped before sending anything or if the message has already been extracted by a previous receive call.
If a message is returned, the channel is disconnected and any subsequent receive operation using this receiver will return an error.
If the supplied timeout
is so large that Rust’s Instant
type can’t represent this point
in the future this falls back to an indefinitely blocking receive operation.
§Panics
Panics if called after this receiver has been polled asynchronously.
sourcepub fn recv_deadline(&self, deadline: Instant) -> Result<T, RecvTimeoutError>
pub fn recv_deadline(&self, deadline: Instant) -> Result<T, RecvTimeoutError>
Like Receiver::recv
, but will not block longer than until deadline
. Returns:
Ok(message)
if there was a message in the channel before the deadline was reached.Err(Timeout)
if no message arrived on the channel before the deadline was reached.Err(Disconnected)
if the sender was dropped before sending anything or if the message has already been extracted by a previous receive call.
If a message is returned, the channel is disconnected and any subsequent receive operation using this receiver will return an error.
§Panics
Panics if called after this receiver has been polled asynchronously.
sourcepub fn into_raw(self) -> *mut ()
pub fn into_raw(self) -> *mut ()
Consumes the Receiver, returning a raw pointer to the channel on the heap.
This is intended to simplify using oneshot channels with some FFI code. The only safe thing to do with the returned pointer is to later reconstruct the Receiver with Receiver::from_raw. Memory will leak if the Receiver is never reconstructed.
sourcepub unsafe fn from_raw(raw: *mut ()) -> Self
pub unsafe fn from_raw(raw: *mut ()) -> Self
Consumes a raw pointer from Receiver::into_raw, recreating the Receiver.
§Safety
This pointer must have come from Receiver<T>::into_raw
with the same message type, T
.
At most one Receiver must exist for a channel at any point in time.
Constructing multiple Receivers from the same raw pointer leads to undefined behavior.