std::atomic_init

Defined in header <atomic>
template< class T >
void atomic_init( std::atomic<T>* obj,
                  typename std::atomic<T>::value_type desired ) noexcept;
(since C++11)
template< class T >
void atomic_init( volatile std::atomic<T>* obj,
                  typename std::atomic<T>::value_type desired ) noexcept;
(since C++11)

Initializes the default-constructed atomic object obj with the value desired. The function is not atomic: concurrent access from another thread, even through an atomic operation, is a data race.

If obj was not default-constructed, the behavior is undefined.

If this function is called twice on the same obj, the behavior is undefined.

Parameters

obj - pointer to an atomic object to initialize
desired - the value to initialize atomic object with

Return value

(none).

Notes

This function is provided for compatibility with C. If the compatibility is not required, std::atomic may be initialized through their non-default constructors.

Example

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR Applied to Behavior as published Correct behavior
P0558R1 C++11 exact type match required because T is deduced from multiple arguments T is deduced from the atomic argument only

See also

(C++11)
constant initialization of an atomic variable of static storage duration
(function macro)
constructs an atomic object
(public member function of std::atomic<T>)

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