# [−][src]Function rayon_core::current_thread_index

    pub fn current_thread_index() -> Option<usize>

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`.

The index for a given thread will not change over the thread's lifetime. However, multiple threads may share the same index if they are in distinct thread-pools.

See also: [the `ThreadPool::current_thread_index()` method].

# Future compatibility note

Currently, every thread-pool (including the global thread-pool) has a fixed number of threads, but this may change in future Rayon versions (see the `num_threads()` method for details). In that case, the index for a thread would not change during its lifetime, but thread indices may wind up being reused if threads are terminated and restarted.

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