Enum mozjs_sys::jsapi::mozilla::MemoryOrdering

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#[repr(u32)]
pub enum MemoryOrdering { Relaxed = 0, ReleaseAcquire = 1, SequentiallyConsistent = 2, }
Expand description

An enum of memory ordering possibilities for atomics.

Memory ordering is the observable state of distinct values in memory. (It’s a separate concept from atomicity, which concerns whether an operation can ever be observed in an intermediate state. Don’t conflate the two!) Given a sequence of operations in source code on memory, it is not always the case that, at all times and on all cores, those operations will appear to have occurred in that exact sequence. First, the compiler might reorder that sequence, if it thinks another ordering will be more efficient. Second, the CPU may not expose so consistent a view of memory. CPUs will often perform their own instruction reordering, above and beyond that performed by the compiler. And each core has its own memory caches, and accesses (reads and writes both) to “memory” may only resolve to out-of-date cache entries – not to the “most recently” performed operation in some global sense. Any access to a value that may be used by multiple threads, potentially across multiple cores, must therefore have a memory ordering imposed on it, for all code on all threads/cores to have a sufficiently coherent worldview.

http://gcc.gnu.org/wiki/Atomic/GCCMM/AtomicSync and http://en.cppreference.com/w/cpp/atomic/memory_order go into more detail on all this, including examples of how each mode works.

Note that for simplicity and practicality, not all of the modes in C++11 are supported. The missing C++11 modes are either subsumed by the modes we provide below, or not relevant for the CPUs we support in Gecko. These three modes are confusing enough as it is!

Variants§

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Relaxed = 0

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ReleaseAcquire = 1

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SequentiallyConsistent = 2

Trait Implementations§

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impl Clone for MemoryOrdering

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fn clone(&self) -> MemoryOrdering

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for MemoryOrdering

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

Formats the value using the given formatter. Read more
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impl Hash for MemoryOrdering

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fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher. Read more
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fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl PartialEq for MemoryOrdering

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

Tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl Copy for MemoryOrdering

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impl Eq for MemoryOrdering

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impl StructuralPartialEq for MemoryOrdering

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> CloneToUninit for T
where T: Clone,

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unsafe fn clone_to_uninit(&self, dst: *mut T)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dst. Read more
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impl<T> Filterable for T

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fn filterable( self, filter_name: &'static str, ) -> RequestFilterDataProvider<T, fn(_: DataRequest<'_>) -> bool>

Creates a filterable data provider with the given name for debugging. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> IntoEither for T

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<T> ErasedDestructor for T
where T: 'static,

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impl<T> MaybeSendSync for T