once_flag Structure
Represents a struct that is used with the template function call_once to ensure that initialization code is called only once, even in the presence of multiple threads of execution.
struct once_flag
{
constexpr once_flag() noexcept;
once_flag(const once_flag&);
once_flag& operator=(const once_flag&);
};
Remarks
The once_flagstruct has only a default constructor.
Objects of type once_flag can be created, but they cannot be copied.
Requirements
Header: mutex
Namespace: std