[][src]Function sgx_tstd::thread::park

pub fn park()

Blocks unless or until the current thread's token is made available.

A call to park does not guarantee that the thread will remain parked forever, and callers should be prepared for this possibility.

park and unpark

Every thread is equipped with some basic low-level blocking support, via the thread::park function and [thread::Thread::unpark][unpark] method. park blocks the current thread, which can then be resumed from another thread by calling the [unpark] method on the blocked thread's handle.

Conceptually, each [Thread] handle has an associated token, which is initially not present:

In other words, each [Thread] acts a bit like a spinlock that can be locked and unlocked using park and unpark.

Notice that being unblocked does not imply any synchronization with someone that unparked this thread, it could also be spurious. For example, it would be a valid, but inefficient, implementation to make both park and [unpark] return immediately without doing anything.

The API is typically used by acquiring a handle to the current thread, placing that handle in a shared data structure so that other threads can find it, and then parking in a loop. When some desired condition is met, another thread calls [unpark] on the handle.

The motivation for this design is twofold: