Struct polling::Event

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pub struct Event {
    pub key: usize,
    pub readable: bool,
    pub writable: bool,
    /* private fields */
}

Expand description

Indicates that a file descriptor or socket can read or write without blocking.

Fields§

§key: usize

Key identifying the file descriptor or socket.

§readable: bool

Can it do a read operation without blocking?

§writable: bool

Can it do a write operation without blocking?

Implementations§

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impl Event

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pub const fn new(key: usize, readable: bool, writable: bool) -> Event

Create a new event.

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pub const fn all(key: usize) -> Event

All kinds of events (readable and writable).

Equivalent to: Event::new(key, true, true)

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pub const fn readable(key: usize) -> Event

Only the readable event.

Equivalent to: Event::new(key, true, false)

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pub const fn writable(key: usize) -> Event

Only the writable event.

Equivalent to: Event::new(key, false, true)

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pub const fn none(key: usize) -> Event

No events.

Equivalent to: Event::new(key, false, false)

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pub fn set_interrupt(&mut self, active: bool)

Add interruption events to this interest.

This usually indicates that the file descriptor or socket has been closed. It corresponds to the EPOLLHUP and POLLHUP events.

Interruption events are only supported on the following platforms:

epoll
poll
IOCP
Event Ports

On other platforms, this function is a no-op.

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pub fn with_interrupt(self) -> Self

Add interruption events to this interest.

This usually indicates that the file descriptor or socket has been closed. It corresponds to the EPOLLHUP and POLLHUP events.

Interruption events are only supported on the following platforms:

epoll
poll
IOCP
Event Ports

On other platforms, this function is a no-op.

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pub fn set_priority(&mut self, active: bool)

Add priority events to this interest.

This indicates that there is urgent data to read. It corresponds to the EPOLLPRI and POLLPRI events.

Priority events are only supported on the following platforms:

epoll
poll
IOCP
Event Ports

On other platforms, this function is a no-op.

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pub fn with_priority(self) -> Self

Add priority events to this interest.

This indicates that there is urgent data to read. It corresponds to the EPOLLPRI and POLLPRI events.

Priority events are only supported on the following platforms:

epoll
poll
IOCP
Event Ports

On other platforms, this function is a no-op.

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pub fn is_interrupt(&self) -> bool

Tell if this event is the result of an interrupt notification.

This usually indicates that the file descriptor or socket has been closed. It corresponds to the EPOLLHUP and POLLHUP events.

Interruption events are only supported on the following platforms:

epoll
poll
IOCP
Event Ports

On other platforms, this always returns false.

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pub fn is_priority(&self) -> bool

Tell if this event is the result of a priority notification.

This indicates that there is urgent data to read. It corresponds to the EPOLLPRI and POLLPRI events.

Priority events are only supported on the following platforms:

epoll
poll
IOCP
Event Ports

On other platforms, this always returns false.

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pub fn is_connect_failed(&self) -> Option<bool>

👎Deprecated since 3.4.0: use is_err in combination of is_hup instead, see documentation for is_err

Tells if this event is the result of a connection failure.

This function checks if a TCP connection has failed. It corresponds to the EPOLLERR or EPOLLHUP event in Linux and CONNECT_FAILED event in Windows IOCP.

§Examples

use std::{io, net};
// Assuming polling and socket2 are included as dependencies in Cargo.toml
use polling::Event;
use socket2::Type;

fn main() -> io::Result<()> {
    let socket = socket2::Socket::new(socket2::Domain::IPV4, Type::STREAM, None)?;
    let poller = polling::Poller::new()?;
    unsafe {
        poller.add(&socket, Event::new(0, true, true))?;
    }
    let addr = net::SocketAddr::new(net::Ipv4Addr::LOCALHOST.into(), 8080);
    socket.set_nonblocking(true)?;
    let _ = socket.connect(&addr.into());

    let mut events = polling::Events::new();

    events.clear();
    poller.wait(&mut events, None)?;

    let event = events.iter().next();

    let event = match event {
        Some(event) => event,
        None => {
            println!("no event");
            return Ok(());
        },
    };

    println!("event: {:?}", event);
    if event
        .is_connect_failed()
        .unwrap_or_default()
    {
        println!("connect failed");
    }

    Ok(())
}

§Returns

Returns Some(true) if the connection has failed, Some(false) if the connection has not failed, or None if the platform does not support detecting this condition.

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pub fn is_err(&self) -> Option<bool>

Tells if this event is the result of a connection failure.

This function checks if an error exist, particularly useful in detecting if TCP connection failed. It corresponds to the EPOLLERR event in Linux and CONNECT_FAILED event in Windows IOCP.

§Caveats

In epoll, a TCP connection failure is indicated by EPOLLERR + EPOLLHUP, though just EPOLLERR is enough to indicate a connection failure. EPOLLHUP may happen when we haven’t event called connect on the socket, but it is still a valid event to check for.

Returns Some(true) if the connection has failed, Some(false) if there is no error, or None if the platform does not support detecting this condition.

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