memory::Aligned_atomic< T > Class Template Reference

Templated class that encapsulates an std::atomic within a byte buffer that is padded to the processor cache-line size. More...

#include <aligned_atomic.h>

Public Member Functions
	Aligned_atomic ()
	Aligned_atomic (T value)
	Aligned_atomic (Aligned_atomic< T > const &rhs)=delete
	Aligned_atomic (Aligned_atomic< T > &&rhs)
virtual	~Aligned_atomic ()
Aligned_atomic< T > &	operator= (Aligned_atomic< T > const &rhs)=delete
Aligned_atomic< T > &	operator= (Aligned_atomic< T > &&rhs)
Aligned_atomic< T > &	operator= (T rhs)
	operator T () const
	Casting operator for directly accessing the value of the underlying std::atomic<T>. More...
bool	operator== (std::nullptr_t rhs) const
	Equality operator to determine if the underlying storage memory is initialized. More...
bool	operator!= (std::nullptr_t rhs) const
	Inequality operator to determine if the underlying storage memory is initialized. More...
bool	operator== (T rhs) const
	Equality operator for determining if the value stored in the underlying std::atomic equals the passed parameter. More...
bool	operator!= (T rhs) const
	Inequality operator for determining if the value stored in the underlying std::atomic differs from the passed parameter. More...
std::atomic< T > *	operator-> ()
const std::atomic< T > *	operator-> () const
std::atomic< T > &	operator* ()
const std::atomic< T > &	operator* () const
size_t	size () const
size_t	allocated_size () const

Private Attributes
size_t	m_storage_size {0}
	The size of the byte buffer. More...
void *	m_storage {nullptr}
	The byte buffer to use as underlying storage. More...
std::atomic< T > *	m_underlying {nullptr}
	The pointer to the underlying std::atomic<T> object. More...

Friends
template<typename Accessor_type >
class	Aligned_atomic_accessor

Detailed Description

template<typename T>
class memory::Aligned_atomic< T >

Templated class that encapsulates an std::atomic within a byte buffer that is padded to the processor cache-line size.

This class purpose is to help prevent false sharing between atomically accessed variables that are contiguous in memory. This is the normal case for arrays or class members declared next to each other.

If the intended usage is none of the above, std::atomic class should be used since the below implementation allocates more memory than needed for storing the intended value (in order to implement the padding to the cache-line).

Constructor & Destructor Documentation

Aligned_atomic() [1/4]

template<typename T >

memory::Aligned_atomic< T >::Aligned_atomic

Aligned_atomic() [2/4]

template<typename T >

memory::Aligned_atomic< T >::Aligned_atomic

(

T

value

)

Aligned_atomic() [3/4]

template<typename T >

memory::Aligned_atomic< T >::Aligned_atomic ( Aligned_atomic< T > const &  rhs )

delete

Aligned_atomic() [4/4]

template<typename T >

memory::Aligned_atomic< T >::Aligned_atomic

(

Aligned_atomic< T > &&

rhs

)

~Aligned_atomic()

template<typename T >

memory::Aligned_atomic< T >::~Aligned_atomic

virtual

Member Function Documentation

allocated_size()

template<typename T >

size_t memory::Aligned_atomic< T >::allocated_size

operator T()

template<typename T >

memory::Aligned_atomic< T >::operator T

Casting operator for directly accessing the value of the underlying std::atomic<T>.

Returns

The value of type T stored in the underlying std::atomic..

operator!=() [1/2]

template<typename T >

bool memory::Aligned_atomic< T >::operator!=

(

std::nullptr_t

rhs

)

const

Inequality operator to determine if the underlying storage memory is initialized.

Parameters

rhs	nullptr value

Returns

true if the underlying storage memory is initialized, false otherwise.

operator!=() [2/2]

template<typename T >

bool memory::Aligned_atomic< T >::operator!=

(

T

rhs

)

const

Inequality operator for determining if the value stored in the underlying std::atomic differs from the passed parameter.

Parameters

rhs	The value to compare with.

Returns

true if the parameter value differs from the value stored in the underlying std::atomic, false otherwise.

operator*() [1/2]

template<typename T >

std::atomic< T > & memory::Aligned_atomic< T >::operator*

operator*() [2/2]

template<typename T >

const std::atomic< T > & memory::Aligned_atomic< T >::operator*

operator->() [1/2]

template<typename T >

std::atomic< T > * memory::Aligned_atomic< T >::operator->

operator->() [2/2]

template<typename T >

const std::atomic< T > * memory::Aligned_atomic< T >::operator->

operator=() [1/3]

template<typename T >

memory::Aligned_atomic< T > & memory::Aligned_atomic< T >::operator=

(

Aligned_atomic< T > &&

rhs

)

operator=() [2/3]

template<typename T >

Aligned_atomic< T > & memory::Aligned_atomic< T >::operator= ( Aligned_atomic< T > const &  rhs )

delete

operator=() [3/3]

template<typename T >

memory::Aligned_atomic< T > & memory::Aligned_atomic< T >::operator=

(

T

rhs

)

operator==() [1/2]

template<typename T >

bool memory::Aligned_atomic< T >::operator==

(

std::nullptr_t

rhs

)

const

Equality operator to determine if the underlying storage memory is initialized.

Parameters

rhs	nullptr value

Returns

true if the underlying storage memory is not initialized, false otherwise.

operator==() [2/2]

template<typename T >

bool memory::Aligned_atomic< T >::operator==

(

T

rhs

)

const

Equality operator for determining if the value stored in the underlying std::atomic equals the passed parameter.

Parameters

rhs	The value to compare with.

Returns

true if the parameter value equals the value stored in the underlying std::atomic, false otherwise.

size()

template<typename T >

size_t memory::Aligned_atomic< T >::size

Friends And Related Function Documentation

Aligned_atomic_accessor

template<typename T >

template<typename Accessor_type >

friend class Aligned_atomic_accessor

friend

Member Data Documentation

m_storage

template<typename T >

void* memory::Aligned_atomic< T >::m_storage {nullptr}

private

The byte buffer to use as underlying storage.

m_storage_size

template<typename T >

size_t memory::Aligned_atomic< T >::m_storage_size {0}

private

The size of the byte buffer.

m_underlying

template<typename T >

std::atomic<T>* memory::Aligned_atomic< T >::m_underlying {nullptr}

private

The pointer to the underlying std::atomic<T> object.

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

• sql/memory/aligned_atomic.h