Implementation of the AtomicWord interface in terms of the C++11 Atomics. More...

#include <atomic_word_cxx11.h>

Public Types
typedef _WordType	WordType
	Underlying value type.

typedef _WordType	WordType
	Underlying value type.

Public Member Functions
	AtomicWord (WordType value=WordType(0))
	Construct a new word with the given initial value.

WordType	load () const
	Gets the current value of this AtomicWord.

WordType	loadRelaxed () const
	Gets the current value of this AtomicWord.

void	store (WordType newValue)
	Sets the value of this AtomicWord to "newValue".

WordType	swap (WordType newValue)
	Atomically swaps the current value of this with "newValue".

WordType	compareAndSwap (WordType expected, WordType newValue)
	Atomic compare and swap.

WordType	fetchAndAdd (WordType increment)
	Get the current value of this, add "increment" and store it, atomically.

WordType	fetchAndSubtract (WordType decrement)
	Get the current value of this, subtract "decrement" and store it, atomically.

WordType	addAndFetch (WordType increment)
	Get the current value of this, add "increment" and store it, atomically.

WordType	subtractAndFetch (WordType decrement)
	Get the current value of this, subtract "decrement" and store it, atomically.

	AtomicWord (WordType value=WordType(0))
	Construct a new word with the given initial value.

WordType	load () const
	Gets the current value of this AtomicWord.

WordType	loadRelaxed () const
	Gets the current value of this AtomicWord.

void	store (WordType newValue)
	Sets the value of this AtomicWord to "newValue".

WordType	swap (WordType newValue)
	Atomically swaps the current value of this with "newValue".

WordType	compareAndSwap (WordType expected, WordType newValue)
	Atomic compare and swap.

WordType	fetchAndAdd (WordType increment)
	Get the current value of this, add "increment" and store it, atomically.

WordType	fetchAndSubtract (WordType decrement)
	Get the current value of this, subtract "decrement" and store it, atomically.

WordType	addAndFetch (WordType increment)
	Get the current value of this, add "increment" and store it, atomically.

WordType	subtractAndFetch (WordType decrement)
	Get the current value of this, subtract "decrement" and store it, atomically.

Detailed Description

template<typename _WordType>
class mongo::AtomicWord< _WordType >

Implementation of the AtomicWord interface in terms of the C++11 Atomics.

Template type for word types supporting indivisible memory operations, implemented in terms of the atomic_intrinsics header.

Effects of operations with "acquire" semantics are visible to other threads before effects of any subsequent operation by the calling thread. Effects of operations with "release" semantics are visible to other processors only after the effects of previous operations on the current thread are visible.

NOTE(schwerin): This implementation assumes that instances are naturally aligned. Instances that are not naturally aligned may operate incorrectly, or not at all. Natural alignment for this purpose means that the byte address of the beginning of the object is an integer multiple of the size of the type, in bytes.

NOTE(schwerin): This is a low level concurrency type, it is very hard to use correctly, and you should not decide to use it lightly.

NOTE(schwerin): This type is and must be a POD type, or per C++11 rules, a "Standard-layout" type.

Member Function Documentation

◆ addAndFetch() [1/2]

template<typename _WordType >

WordType mongo::AtomicWord< _WordType >::addAndFetch ( WordType increment )

inline

Get the current value of this, add "increment" and store it, atomically.

Returns the value of this after incrementing.

Has acquire and release semantics.

◆ addAndFetch() [2/2]

template<typename _WordType >

WordType mongo::AtomicWord< _WordType >::addAndFetch ( WordType increment )

inline

Get the current value of this, add "increment" and store it, atomically.

Returns the value of this after incrementing.

Has acquire and release semantics.

◆ compareAndSwap() [1/2]

template<typename _WordType >

WordType mongo::AtomicWord< _WordType >::compareAndSwap	(	WordType	expected,
		WordType	newValue
	)

inline

Atomic compare and swap.

If this value equals "expected", sets this to "newValue". Always returns the original of this.

Has acquire and release semantics.

◆ compareAndSwap() [2/2]

template<typename _WordType >

WordType mongo::AtomicWord< _WordType >::compareAndSwap	(	WordType	expected,
		WordType	newValue
	)

inline

Atomic compare and swap.

If this value equals "expected", sets this to "newValue". Always returns the original of this.

Has acquire and release semantics.

◆ fetchAndAdd() [1/2]

template<typename _WordType >

WordType mongo::AtomicWord< _WordType >::fetchAndAdd ( WordType increment )

inline

Get the current value of this, add "increment" and store it, atomically.

Returns the value of this before incrementing.

Has acquire and release semantics.

◆ fetchAndAdd() [2/2]

template<typename _WordType >

WordType mongo::AtomicWord< _WordType >::fetchAndAdd ( WordType increment )

inline

Get the current value of this, add "increment" and store it, atomically.

Returns the value of this before incrementing.

Has acquire and release semantics.

◆ fetchAndSubtract() [1/2]

template<typename _WordType >

WordType mongo::AtomicWord< _WordType >::fetchAndSubtract ( WordType decrement )

inline

Get the current value of this, subtract "decrement" and store it, atomically.

Returns the value of this before decrementing.

Has acquire and release semantics.

◆ fetchAndSubtract() [2/2]

template<typename _WordType >

WordType mongo::AtomicWord< _WordType >::fetchAndSubtract ( WordType decrement )

inline

Get the current value of this, subtract "decrement" and store it, atomically.

Returns the value of this before decrementing.

Has acquire and release semantics.

◆ load() [1/2]

template<typename _WordType >

WordType mongo::AtomicWord< _WordType >::load ( ) const

inline

Gets the current value of this AtomicWord.

Has acquire and release semantics.

◆ load() [2/2]

template<typename _WordType >

WordType mongo::AtomicWord< _WordType >::load ( ) const

inline

Gets the current value of this AtomicWord.

Has acquire and release semantics.

◆ loadRelaxed() [1/2]

template<typename _WordType >

WordType mongo::AtomicWord< _WordType >::loadRelaxed ( ) const

inline

Gets the current value of this AtomicWord.

Has relaxed semantics.

◆ loadRelaxed() [2/2]

template<typename _WordType >

WordType mongo::AtomicWord< _WordType >::loadRelaxed ( ) const

inline

Gets the current value of this AtomicWord.

Has relaxed semantics.

◆ store() [1/2]

template<typename _WordType >

void mongo::AtomicWord< _WordType >::store ( WordType newValue )

inline

Sets the value of this AtomicWord to "newValue".

Has acquire and release semantics.

◆ store() [2/2]

template<typename _WordType >

void mongo::AtomicWord< _WordType >::store ( WordType newValue )

inline

Sets the value of this AtomicWord to "newValue".

Has acquire and release semantics.

◆ subtractAndFetch() [1/2]

template<typename _WordType >

WordType mongo::AtomicWord< _WordType >::subtractAndFetch ( WordType decrement )

inline

Get the current value of this, subtract "decrement" and store it, atomically.

Returns the value of this after decrementing.

Has acquire and release semantics.

◆ subtractAndFetch() [2/2]

template<typename _WordType >

WordType mongo::AtomicWord< _WordType >::subtractAndFetch ( WordType decrement )

inline

Get the current value of this, subtract "decrement" and store it, atomically.

Returns the value of this after decrementing.

Has acquire and release semantics.

◆ swap() [1/2]

template<typename _WordType >

WordType mongo::AtomicWord< _WordType >::swap ( WordType newValue )

inline

Atomically swaps the current value of this with "newValue".

Returns the old value.

Has acquire and release semantics.

◆ swap() [2/2]

template<typename _WordType >

WordType mongo::AtomicWord< _WordType >::swap ( WordType newValue )

inline

Atomically swaps the current value of this with "newValue".

Returns the old value.

Has acquire and release semantics.

The documentation for this class was generated from the following files:

src/mongo/platform/atomic_word_cxx11.h
src/mongo/platform/atomic_word_intrinsics.h

Public Types

Public Member Functions

Detailed Description

Member Function Documentation

◆ addAndFetch() [1/2]

◆ addAndFetch() [2/2]

◆ compareAndSwap() [1/2]

◆ compareAndSwap() [2/2]

◆ fetchAndAdd() [1/2]

◆ fetchAndAdd() [2/2]

◆ fetchAndSubtract() [1/2]

◆ fetchAndSubtract() [2/2]

◆ load() [1/2]

◆ load() [2/2]

◆ loadRelaxed() [1/2]

◆ loadRelaxed() [2/2]

◆ store() [1/2]

◆ store() [2/2]

◆ subtractAndFetch() [1/2]

◆ subtractAndFetch() [2/2]

◆ swap() [1/2]

◆ swap() [2/2]