Alice Ryhl

Since this PR appears to have gotten stuck, I'll close it for now. Feel free to reopen if you find a solution to the header being too large.

I want to note that the standard library argues that its mutex should be UnwindSafe because it has poisoning, and our mutexes doesn't.

If we are going to the trouble to implement this, perhaps it should simply be implemented for `Semaphore` instead, which would give us the feature on `OnceCell` too for free.

Not sure what you mean by "gate" semaphore? However, closing the semaphore seems like the ideal signal to use for this.

You can do that by having an empty `Semaphore` that you close upon opening it. The `acquire` calls will return when you close it. Of course, a dedicated primitive could...

I would prefer a PR that implements a way to wait for a `Semaphore` to be closed. It can be followed up by a PR that implements `OnceCell::wait` using it.

Well, it seemed useful enough to me, but I don't mind dropping plans of supporting that for `Semaphore`.

Here's a proposal for fixing this: > ## The JoinHandle waker > > There are two bits that control access to the JoinHandle waker field: > JOIN_WAKER and JOIN_INTEREST. The...

I already have a 75% complete implementation of this.

The current status of this is that the only way to avoid it is to bypass the standard library and directly call into `libc` for the read and write calls.