Function rustc_rayon::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.