class
<mutex>

std::adopt_lock_t

struct adopt_lock_t {};
Type of adopt_lock
This is an empty class used as the type of adopt_lock.

Passing adopt_lock to the constructor of unique_lock of lock_guard, makes the object to not lock the mutex object, and assume instead that it is already locked by the current thread.

See also

adopt_lock
Adopt lock (object )
defer_lock_t
Type of defer_lock (class )
try_to_lock_t
Type of try_to_lock (class )