//?atomic::compare_exchange_weak?example:
#include????????//?std::cout
#include??????????//?std::atomic
#include??????????//?std::thread
#include??????????//?std::vector
//?a?simple?global?linked?list:
struct?Node?{?int?value;?Node*?next;?};
std::atomic?list_head（nullptr）;
void?append（int?val）?{?????//?append?an?element?to?the?list
	Node*?newNode?=?new?Node{?vallist_head?};
	//?next?is?the?same?as:?list_head?=?newNode?but?in?a?thread-safe?way:
	while?（!list_head.compare_exchange_weak（newNode->next?newNo