Struct FixedThreadPool 

pub struct FixedThreadPool { /* private fields */ }

Fixed-size thread pool implementing ExecutorService.

FixedThreadPool prestarts a fixed number of worker threads and does not support runtime pool-size changes. Use super::ThreadPool when dynamic core/maximum sizes or keep-alive policies are required.

Implementations

impl FixedThreadPool

pub fn new(pool_size: usize) -> Result<Self, ThreadPoolBuildError>

Creates a fixed thread pool with pool_size prestarted workers.

Parameters

• pool_size - Number of worker threads.

Returns

A fixed thread pool.

Errors

Returns ThreadPoolBuildError if the worker count is zero or a worker cannot be spawned.

pub fn builder() -> FixedThreadPoolBuilder

Creates a fixed pool builder.

Returns

Builder with CPU parallelism defaults.

pub fn pool_size(&self) -> usize

Returns the fixed worker count.

Returns

Number of workers in this pool.

pub fn queued_count(&self) -> usize

Returns the queued task count.

Returns

Number of accepted tasks waiting to run.

pub fn running_count(&self) -> usize

Returns the running task count.

Returns

Number of tasks currently held by workers.

pub fn live_worker_count(&self) -> usize

Returns the live worker count.

Returns

Number of worker loops that have not exited.

pub fn stats(&self) -> ThreadPoolStats

Returns a point-in-time stats snapshot.

Returns

Snapshot containing queue, worker, and lifecycle counters.

Trait Implementations

impl Drop for FixedThreadPool

fn drop(&mut self)

Requests graceful shutdown when the pool handle is dropped.

impl ExecutorService for FixedThreadPool

fn submit_callable<C, R, E>( &self, task: C, ) -> Result<Self::Handle<R, E>, RejectedExecution>

where C: Callable<R, E> + Send + 'static, R: Send + 'static, E: Send + 'static,

Accepts a callable and queues it for fixed pool workers.

Parameters

• task - Callable to execute on a fixed pool worker.

Returns

A TaskHandle for the accepted task.

Errors

Returns RejectedExecution::Shutdown after shutdown or RejectedExecution::Saturated when a bounded queue is full.

fn shutdown(&self)

Stops accepting new work and drains accepted queued tasks.

fn shutdown_now(&self) -> ShutdownReport

Stops accepting work and cancels queued tasks.

Returns

A count-based shutdown report.

fn is_shutdown(&self) -> bool

Returns whether shutdown has been requested.

Returns

true when this pool no longer accepts new work.

fn is_terminated(&self) -> bool

Returns whether this pool is fully terminated.

Returns

true after shutdown and after all workers have exited.

fn await_termination(&self) -> Self::Termination<'_>

Waits until this fixed pool has terminated.

Returns

A future that blocks the polling thread until termination.

type Handle<R, E> = TaskHandle<R, E> where R: Send + 'static, E: Send + 'static

Handle returned for an accepted task.

type Termination<'a> = Pin<Box<dyn Future<Output = ()> + Send + 'a>> where Self: 'a

Future returned when waiting for service termination.

fn submit<T, E>( &self, task: T, ) -> Result<Self::Handle<(), E>, RejectedExecution>

where T: Runnable<E> + Send + 'static, E: Send + 'static,

Submits a runnable task to this service.