Struct DispatchSemaphore 

pub struct DispatchSemaphore { /* private fields */ }

Dispatch semaphore.

Implementations

impl DispatchSemaphore

pub fn new(value: isize) -> DispatchRetained<DispatchSemaphore>

Creates new counting semaphore with an initial value.

Passing zero for the value is useful for when two threads need to reconcile the completion of a particular event. Passing a value greater than zero is useful for managing a finite pool of resources, where the pool size is equal to the value.

Parameter value: The starting value for the semaphore. Passing a value less than zero will cause NULL to be returned.

Returns: The newly created semaphore, or NULL on failure.

pub fn wait(self: &DispatchSemaphore, timeout: DispatchTime) -> isize

Wait (decrement) for a semaphore.

Decrement the counting semaphore. If the resulting value is less than zero, this function waits for a signal to occur before returning. If the timeout is reached without a signal being received, the semaphore is re-incremented before the function returns.

Parameter dsema: The semaphore. The result of passing NULL in this parameter is undefined.

Parameter timeout: When to timeout (see dispatch_time). As a convenience, there are the DISPATCH_TIME_NOW and DISPATCH_TIME_FOREVER constants.

Returns: Returns zero on success, or non-zero if the timeout occurred.

pub fn signal(self: &DispatchSemaphore) -> isize

Signal (increment) a semaphore.

Increment the counting semaphore. If the previous value was less than zero, this function wakes a waiting thread before returning.

Parameter dsema: The counting semaphore. The result of passing NULL in this parameter is undefined.

Returns: This function returns non-zero if a thread is woken. Otherwise, zero is returned.

impl DispatchSemaphore

pub fn try_acquire( &self, timeout: DispatchTime, ) -> Result<DispatchSemaphoreGuard, WaitError>

Attempt to acquire the DispatchSemaphore and return a DispatchSemaphoreGuard.

Errors

Return WaitError::TimeOverflow if the passed timeout is too big.

Return WaitError::Timeout in case of timeout.

Trait Implementations

impl AsRef<AnyObject> for DispatchSemaphore

Available on crate feature objc2 only.

fn as_ref(&self) -> &AnyObject

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<DispatchSemaphore> for DispatchSemaphore

fn as_ref(&self) -> &Self

Converts this type into a shared reference of the (usually inferred) input type.

impl Debug for DispatchSemaphore

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

Formats the value using the given formatter.

impl DispatchObject for DispatchSemaphore

fn retain(&self) -> DispatchRetained<Self>

Increment the reference count of the object.

fn context(&self) -> *mut c_void

TODO.

unsafe fn set_context(&self, context: *mut c_void)

TODO.

unsafe fn set_finalizer_f(&self, finalizer: dispatch_function_t)

TODO.

fn set_finalizer<F>(&self, destructor: F)

where F: Send + FnOnce(),

Set the finalizer function for the object.

unsafe fn set_target_queue(&self, queue: &DispatchQueue)

Set the target DispatchQueue of this object.

unsafe fn set_qos_class_floor( &self, qos_class: DispatchQoS, relative_priority: i32, ) -> Result<(), QualityOfServiceClassFloorError>

Set the QOS class floor on a dispatch queue, source or workloop.

fn activate(&self)

Activate the object.

fn suspend(&self)

Suspend the invocation of functions on the object.

fn resume(&self)

Resume the invocation of functions on the object.

impl Hash for DispatchSemaphore

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Message for DispatchSemaphore

Available on crate feature objc2 only.

fn retain(&self) -> Retained<Self>

where Self: Sized,

Increment the reference count of the receiver.

impl PartialEq for DispatchSemaphore

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

Compare this [$type] with another using pointer equality.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl RefEncode for DispatchSemaphore

Available on crate feature objc2 only.

const ENCODING_REF: Encoding = objc2::encode::Encoding::Object

The Objective-C type-encoding for a reference of this type.

impl Eq for DispatchSemaphore

impl Send for DispatchSemaphore

impl Sync for DispatchSemaphore