Re: [PATCH v2 4/7] rust: file: add `FileDescriptorReservation`

[Alice Ryhl <aliceryhl@google.com>]

On Fri, Dec 8, 2023 at 8:37 AM Benno Lossin <benno.lossin@proton.me> wrote:
> > +/// Zero-sized type to mark types not [`Send`].
> > +///
> > +/// Add this type as a field to your struct if your type should not be sent to a different task.
> > +/// Since [`Send`] is an auto trait, adding a single field that is `!Send` will ensure that the
> > +/// whole type is `!Send`.
> > +///
> > +/// If a type is `!Send` it is impossible to give control over an instance of the type to another
> > +/// task. This is useful when a type stores task-local information for example file descriptors.
> > +pub type NotThreadSafe = PhantomData<*mut ()>;
>
> This should be in its own commit.

Will do.

> Then you can also change the usages of `PhantomData<*mut ()>` in
> `Guard` and `TaskRef`.

Will do.

> It would be nice to use `NotThreadSafe` as the value instead of
> `PhantomData`, since it is a bit confusing...

That doesn't compile, unfortunately.

> I think we might be able to also have a constant with the same name
> that is just `pub const NotThreadSafe: NotThreadSafe = PhantomData;`.

I can try to get this to work, but I worry that they will shadow each other.

Alice