honey::atomic Namespace Reference

Atomic operations. More...

Classes
class	Op
	Methods to perform thread-safe atomic read/write operations. More...
struct	SwapType
	Get the smallest atomically-swappable type that is large enough to hold T. More...

Typedefs
typedef platform::SwapMaxType	SwapMaxType
	Largest atomically-swappable type. More...

Enumerations
enum	Order {   Order::relaxed, Order::consume, Order::acquire, Order::release,   Order::acqRel, Order::seqCst }
	Atomic memory order for concurrent synchronization between threads. More...

Detailed Description

Atomic operations.

Typedef Documentation

typedef platform::SwapMaxType honey::atomic::SwapMaxType

Largest atomically-swappable type.

Enumeration Type Documentation

enum honey::atomic::Order

strong

Atomic memory order for concurrent synchronization between threads.

Compilers and hardware optimize ops assuming the environment is single-threaded, this causes race conditions in a concurrent environment.
The safest but slowest order is sequential consistency, load/store ops will not be optimized and thus will be executed in the order as written.
The fastest but unsafest order is relaxed, load/store ops can be fully optimized and thus re-ordered.
Release and acquire pairs provide a middle ground that allows some re-ordering.
A release on an atomic in thread 1 will synchronize with an acquire on that same atomic in thread 2.
Synchronization guarantees that all operations before the release in thread 1 will be executed before the acquire in thread 2.

See also

std::memory_order for details.

Enumerator
relaxed	No order constraint, same as plain load/store. Unsafe but best performance.
consume	Must be a load op. Synchronize with a prior release in another thread, but only synchronize ops dependent on this load.
acquire	Must be a load op. Synchronize with a prior release in another thread.
release	Must be a store op. Synchronize with a later acquire in another thread.
acqRel	Must be a load-modify-store op. Performs both acquire and release.
seqCst	Sequential consistency, safe total order but least performance.