Instances of std::once_flag
are used with std::call_once
to ensure that a particular function is called exactly once, even if multiple
threads invoke the call concurrently.
Instances of std::once_flag
are neither CopyConstructible
, CopyAssignable
,
MoveConstructible
nor
MoveAssignable
.
struct once_flag { constexpr once_flag(); once_flag(once_flag const& ) = delete; once_flag& operator=(once_flag const& ) = delete; }; // just::thread specific #define _JSS_STATIC_ONCE_FLAG(name) [`unspecified] #define _JSS_EXTERN_ONCE_FLAG(name) [`unspecified]
#include <mutex>