immer::atom< T, MemoryPolicy > Class Template Reference

#include <atom.hpp>

Classes
struct	get_gc_atom_impl
struct	get_refcount_atom_impl

Public Types
using	box_type = box< T, MemoryPolicy >
using	value_type = T
using	memory_policy = MemoryPolicy

Public Member Functions
	atom (const atom &)=delete
	atom (atom &&)=delete
void	operator= (const atom &)=delete
void	operator= (atom &&)=delete
	atom (box_type v={})
atom &	operator= (box_type b)
	operator box_type () const
	operator value_type () const
box_type	load () const
void	store (box_type b)
box_type	exchange (box_type b)
template<typename Fn >
box_type	update (Fn &&fn)

Private Types
using	impl_t = typename std::conditional_t< std::is_same< typename MemoryPolicy::refcount, no_refcount_policy >::value, get_gc_atom_impl, get_refcount_atom_impl >::template apply< T, MemoryPolicy >::type

Private Attributes
impl_t	impl_

Detailed Description

template<typename T, typename MemoryPolicy = default_memory_policy>
class immer::atom< T, MemoryPolicy >

Stores for boxed values of type T in a thread-safe manner.

See also

box

.. warning:: If memory policy used includes thread unsafe reference counting, no no thread safety is assumed, and the atom becomes thread unsafe too!

.. note:: box<T> provides a value based box of type T, this is, we can think about it as a value-based version of std::shared_ptr. In a similar fashion, atom<T> is in spirit the value-based equivalent of C++20 std::atomic_shared_ptr. However, the API does not follow std::atomic interface closely, since it attempts to be a higher level construction, most similar to Clojure's (atom). It is remarkable in particular that, since box<T> underlying object is immutable, using atom<T> is fully thread-safe in ways that std::atmic_shared_ptr is not. This is so because dereferencing the underlying pointer in a std::atomic_share_ptr may require further synchronization, in particular when invoking non-const methods.

Definition at line 154 of file atom.hpp.

Member Typedef Documentation

box_type

template<typename T , typename MemoryPolicy = default_memory_policy>

using immer::atom< T, MemoryPolicy >::box_type = box<T, MemoryPolicy>

Definition at line 157 of file atom.hpp.

impl_t

template<typename T , typename MemoryPolicy = default_memory_policy>

using immer::atom< T, MemoryPolicy >::impl_t = typename std::conditional_t< std::is_same<typename MemoryPolicy::refcount, no_refcount_policy>::value, get_gc_atom_impl, get_refcount_atom_impl >::template apply<T, MemoryPolicy>::type

private

Definition at line 254 of file atom.hpp.

memory_policy

template<typename T , typename MemoryPolicy = default_memory_policy>

using immer::atom< T, MemoryPolicy >::memory_policy = MemoryPolicy

Definition at line 159 of file atom.hpp.

value_type

template<typename T , typename MemoryPolicy = default_memory_policy>

using immer::atom< T, MemoryPolicy >::value_type = T

Definition at line 158 of file atom.hpp.

Constructor & Destructor Documentation

atom() [1/3]

template<typename T , typename MemoryPolicy = default_memory_policy>

immer::atom< T, MemoryPolicy >::atom ( const atom< T, MemoryPolicy > &  )

delete

atom() [2/3]

template<typename T , typename MemoryPolicy = default_memory_policy>

immer::atom< T, MemoryPolicy >::atom ( atom< T, MemoryPolicy > &&  )

delete

atom() [3/3]

template<typename T , typename MemoryPolicy = default_memory_policy>

immer::atom< T, MemoryPolicy >::atom ( box_type  v = {} )

inline

Constructs an atom holding a value b;

Definition at line 169 of file atom.hpp.

Member Function Documentation

exchange()

template<typename T , typename MemoryPolicy = default_memory_policy>

box_type immer::atom< T, MemoryPolicy >::exchange ( box_type  b )

inline

Stores a new value and returns the old value, in a thread-safe manner.

Definition at line 209 of file atom.hpp.

References immer::atom< T, MemoryPolicy >::impl_.

load()

template<typename T , typename MemoryPolicy = default_memory_policy>

box_type immer::atom< T, MemoryPolicy >::load ( ) const

inline

Reads the currently stored value in a thread-safe manner.

Definition at line 197 of file atom.hpp.

References immer::atom< T, MemoryPolicy >::impl_.

operator box_type()

template<typename T , typename MemoryPolicy = default_memory_policy>

immer::atom< T, MemoryPolicy >::operator box_type ( ) const

inline

Reads the currently stored value in a thread-safe manner.

Definition at line 185 of file atom.hpp.

References immer::atom< T, MemoryPolicy >::impl_.

operator value_type()

template<typename T , typename MemoryPolicy = default_memory_policy>

immer::atom< T, MemoryPolicy >::operator value_type ( ) const

inline

Reads the currently stored value in a thread-safe manner.

Definition at line 191 of file atom.hpp.

References immer::atom< T, MemoryPolicy >::impl_.

operator=() [1/3]

template<typename T , typename MemoryPolicy = default_memory_policy>

void immer::atom< T, MemoryPolicy >::operator= ( const atom< T, MemoryPolicy > &  )

delete

operator=() [2/3]

template<typename T , typename MemoryPolicy = default_memory_policy>

void immer::atom< T, MemoryPolicy >::operator= ( atom< T, MemoryPolicy > &&  )

delete

operator=() [3/3]

template<typename T , typename MemoryPolicy = default_memory_policy>

atom& immer::atom< T, MemoryPolicy >::operator= ( box_type  b )

inline

Sets a new value in the atom.

Definition at line 176 of file atom.hpp.

References immer::atom< T, MemoryPolicy >::impl_.

store()

template<typename T , typename MemoryPolicy = default_memory_policy>

void immer::atom< T, MemoryPolicy >::store ( box_type  b )

inline

Stores a new value in a thread-safe manner.

Definition at line 203 of file atom.hpp.

References immer::atom< T, MemoryPolicy >::impl_.

update()

template<typename T , typename MemoryPolicy = default_memory_policy>

template<typename Fn >

box_type immer::atom< T, MemoryPolicy >::update ( Fn &&  fn )

inline

Stores the result of applying fn to the current value atomically and returns the new resulting value.

.. warning:: fn must be a pure function and have no side effects! The function might be evaluated multiple times when multiple threads content to update the value.

Definition at line 225 of file atom.hpp.

References immer::atom< T, MemoryPolicy >::impl_.

Member Data Documentation

impl_

template<typename T , typename MemoryPolicy = default_memory_policy>

impl_t immer::atom< T, MemoryPolicy >::impl_

private

Definition at line 256 of file atom.hpp.

Referenced by immer::atom< T, MemoryPolicy >::exchange(), immer::atom< T, MemoryPolicy >::load(), immer::atom< T, MemoryPolicy >::operator box_type(), immer::atom< T, MemoryPolicy >::operator value_type(), immer::atom< T, MemoryPolicy >::operator=(), immer::atom< T, MemoryPolicy >::store(), and immer::atom< T, MemoryPolicy >::update().

---

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

• src/immer/atom.hpp