From cppreference.com
Provided only when T is an integral type other than cvbool or a pointer-to-object type
value_typefetch_max(value_typearg,std::memory_orderorder=std::memory_order_seq_cst)constnoexcept;(since C++26)Atomically replaces the current value of the referenced object with the result of
of the value and arg. That is, it performs atomic maximum operation. The operation is a read-modify-write operation. Memory is affected according to the value of order.
If T is a pointer type and the pointers point to different complete objects (or subobjects thereof),
does not establish a
.
This overload participates in overload resolution only if std::is_const_v<T> is false.
Parameters
arg - the other argument of
order - memory order constraints to enforce Return value
The value immediately preceding the effects of this function in the
of *this.
Notes
macroValueStdFeature
(C++26)Atomic minimum/maximum Example