單例模式
讓一個 class 只會產生唯一一個 instance。
cpp
class Manager {
public:
static Manager& get() {
static Manager inst;
return inst;
}
Manager(Manager const&) = delete;
void operator=(Manager const&) = delete;
private:
Manager() = default;
};thread-safe?
In C++11, it is thread safe. According to the standard, §6.7 [stmt.dcl] p4:
If control enters the declaration concurrently while the variable is being initialized, the concurrent execution shall wait for completion of the initialization.