std::atomic_fetch_max, std::atomic_fetch_max_explicit

 

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Defined in header <atomic>
template< class T > T atomic_fetch_max( std::atomic<T>* obj,                     typename std::atomic<T>::value_type arg ) noexcept;	(1)	(since C++26)
template< class T > T atomic_fetch_max( volatile std::atomic<T>* obj,                     typename std::atomic<T>::value_type arg ) noexcept;	(2)	(since C++26)
template< class T > T atomic_fetch_max_explicit( std::atomic<T>* obj,                              typename std::atomic<T>::value_type arg,                              std::memory_order order ) noexcept;	(3)	(since C++26)
template< class T > T atomic_fetch_max_explicit( volatile std::atomic<T>* obj,                              typename std::atomic<T>::value_type arg,                              std::memory_order order ) noexcept;	(4)	(since C++26)

Atomically replaces the value pointed by obj with the result of std::max between the old value of obj and arg. Returns the value obj held previously. The operation is performed as if the following was executed:

1,2) obj->fetch_max(arg)

3,4) obj->fetch_max(arg, order)

If std::atomic<T> has no fetch_max member (this member is only provided for integral and pointer types except bool), the program is ill-formed.

Parameters

obj	-	pointer to the atomic object to modify
arg	-	the value to std::max with the value stored in the atomic object
order	-	the memory synchronization ordering

Return value

The value immediately preceding the effects of this function in the modification order of *obj.

Notes

Feature-test macro	Value	Std	Feature
__cpp_lib_atomic_min_max	202403L	(C++26)	Atomic minimum/maximum

See also

fetch_max (C++26)	atomically performs std::max between the argument and the value of the atomic object and obtains the value held previously (public member function of std::atomic<T>)
atomic_fetch_minatomic_fetch_min_explicit (C++26)(C++26)	replaces the atomic object with the result of std::min with a non-atomic argument and obtains the previous value of the atomic (function template)