Crate rayon_core [] [src]

Under construction

Restricting multiple versions

In order to ensure proper coordination between threadpools, and especially to make sure there's only one global threadpool, rayon-core is actively restricted from building multiple versions of itself into a single target. You may see a build error like this in violation:

error: native library `rayon-core` is being linked to by more
than one package, and can only be linked to by one package

While we strive to keep rayon-core semver-compatible, it's still possible to arrive at this situation if different crates have overly restrictive tilde or inequality requirements for rayon-core. The conflicting requirements will need to be resolved before the build will succeed.

Structs

Configuration

Contains the rayon thread pool configuration.

FnContext

Provides the calling context to a closure called by join_context.

Scope

Represents a fork-join scope which can be used to spawn any number of tasks. See scope() for more information.

ThreadPool

Functions

current_num_threads

Returns the number of threads in the current registry. If this code is executing within a Rayon thread-pool, then this will be the number of threads for the thread-pool of the current thread. Otherwise, it will be the number of threads for the global thread-pool.

current_thread_has_pending_tasks

If called from a Rayon worker thread, indicates whether that thread's local deque still has pending tasks. Otherwise, returns None. For more information, see the ThreadPool::current_thread_has_pending_tasks() method.

current_thread_index

If called from a Rayon worker thread, returns the index of that thread within its current pool; if not called from a Rayon thread, returns None.

initialize

Initializes the global thread pool. This initialization is optional. If you do not call this function, the thread pool will be automatically initialized with the default configuration. In fact, calling initialize is not recommended, except for in two scenarios:

join

The join function takes two closures and potentially runs them in parallel. It returns a pair of the results from those closures.

join_context

The join_context function is identical to join, except the closures have a parameter that provides context for the way the closure has been called, especially indicating whether they're executing on a different thread than where join_context was called. This will occur if the second job is stolen by a different thread, or if join_context was called from outside the thread pool to begin with.

scope

Create a "fork-join" scope s and invokes the closure with a reference to s. This closure can then spawn asynchronous tasks into s. Those tasks may run asynchronously with respect to the closure; they may themselves spawn additional tasks into s. When the closure returns, it will block until all tasks that have been spawned into s complete.

spawn

Fires off a task into the Rayon threadpool in the "static" or "global" scope. Just like a standard thread, this task is not tied to the current stack frame, and hence it cannot hold any references other than those with 'static lifetime. If you want to spawn a task that references stack data, use the scope() function to create a scope.