Struct EventFd 

#[repr(transparent)]
pub struct EventFd(OwnedFd);

An eventfd file descriptor.

Tuple Fields

0: OwnedFd

Implementations

impl EventFd

pub fn new() -> Result<Self>

EventFd::from_value_and_flags with init_val = 0 and flags = EfdFlags::empty().

pub fn from_value_and_flags(init_val: u32, flags: EfdFlags) -> Result<Self>

Constructs EventFd with the given init_val and flags.

Wrapper around libc::eventfd.

pub fn from_flags(flags: EfdFlags) -> Result<Self>

EventFd::from_value_and_flags with init_val = 0 and given flags.

pub fn from_value(init_val: u32) -> Result<Self>

EventFd::from_value_and_flags with given init_val and flags = EfdFlags::empty().

pub unsafe fn from_owned_fd(fd: OwnedFd) -> Self

Constructs an EventFd wrapping an existing OwnedFd.

Safety

OwnedFd is a valid eventfd.

pub fn write(&self, value: u64) -> Result<usize>

Enqueues value triggers, i.e., adds the integer value supplied in value to the counter.

The next value calls to poll, select or epoll will return immediately.

EventFd::write with value.

pub fn read(&self) -> Result<u64>

Reads the value from the file descriptor.

• If EFD_SEMAPHORE was not specified and the eventfd counter has a nonzero value, then this function returns an u64 containing that value, and the counter’s value is reset to zero.

• If EFD_SEMAPHORE was specified and the eventfd counter has a nonzero value, then this function returns an u64 containing the value 1, and the counter’s value is decremented by 1.

• If the eventfd counter is zero at the time of this call, then the call either blocks until the counter becomes nonzero (at which time, this function proceeds as described above) or fails with the error EAGAIN if the file descriptor has been made nonblocking with EFD_NONBLOCK.

Trait Implementations

impl AsFd for EventFd

fn as_fd(&self) -> BorrowedFd<'_>

Borrows the file descriptor.

impl AsRawFd for EventFd

fn as_raw_fd(&self) -> RawFd

Extracts the raw file descriptor.

impl Debug for EventFd

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

Formats the value using the given formatter.

impl From<EventFd> for OwnedFd

fn from(value: EventFd) -> Self

Converts to this type from the input type.