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 ;	(1)	(since C++11) (deprecated in C++20)
template < class T > void atomic_init ( volatile std:: atomic < T > * obj, typename std:: atomic < T > :: value_type desired ) noexcept ;	(2)	(since C++11) (deprecated in C++20)

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, or 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

This section is incomplete Reason: no 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 was required because T was deduced from multiple arguments	T is only deduced from obj

See also

ATOMIC_VAR_INIT (C++11) (deprecated in C++20)	constant initialization of an atomic variable of static storage duration (function macro)
(constructor)	constructs an atomic object (public member function of std::atomic<T> )
C documentation for atomic_init