Enum SyncOpt 

#[repr(u8)]
pub enum SyncOpt {
    AcqRelOps = 0,
    Fence = 1,
    None = 2,
}

An enumeration of various synchronization options to use when performing memory transfer operations with well_defined_copy_to / well_defined_copy_from.

AcqRelOps

Use either Ordering::Acquire (CopyFrom) or Ordering::Release (CopyTo) on every atomic load/store operation during the transfer to/from the shared buffer.

Fence

Use either an Ordering::Acquire thread fence (CopyFrom) after the transfer operation, or an Ordering::Release (CopyTo) thread fence before the operation, and Ordering::Relaxed for each of the atomic load/store operations during the transfer.

None

Simply use Ordering::Relaxed for each of the atomic load/store operations during the transfer. Do not actually introduce any explicit synchronization behavior.

WARNING: Use cases for this transfer mode tend to be unusual. Users will almost always want some form of synchronization to take place during their transfers. One example of where it may be appropriate to use SyncOpt::None might be a situation where users are attempting to observe the state of more than one object while inside of a sequence lock read transaction, and the user has decided that it is better to use a thread fence than to use acquire semantics on each element transferred. Such a sequence might look something like this:

let mut foo1 = Foo::default();
let mut foo2 = Foo::default();
let mut bar1 = Bar::default();
let mut bar2 = Bar::default();
// ...
src_foo1.read::<SYNC_OPT_NONE>(&mut foo1);
src_foo2.read::<SYNC_OPT_NONE>(&mut foo2);
src_bar1.read::<SYNC_OPT_NONE>(&mut bar1);
src_bar2.read::<SYNC_OPT_FENCE>(&mut bar2);

Note that it is the last transfer operation which includes the fence. In the case of a CopyTo operation (when publishing data) it would be the first operation which included the fence, not the last.

Variants

AcqRelOps = 0

Fence = 1

None = 2

Implementations

impl SyncOpt

pub const fn from_u8(val: u8) -> Self

Trait Implementations

impl Clone for SyncOpt

fn clone(&self) -> SyncOpt

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for SyncOpt

impl Debug for SyncOpt

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for SyncOpt

impl PartialEq for SyncOpt

fn eq(&self, other: &SyncOpt) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for SyncOpt