std::unique_lock::~unique_lock

From cppreference.com
< cpplrm; | threadlrm; | unique lock
Thread support library
Threads
(C++11)
this_thread namespace
(C++11)
(C++11)
(C++11)
Mutual exclusion
(C++11)
Generic lock management
(C++11)
(C++11)
(C++11)
(C++11)(C++11)(C++11)
(C++11)
(C++11)
Condition variables
(C++11)
Futures
(C++11)
(C++11)
(C++11)
(C++11)
~unique_lock();
(since C++11)

Destroys the lock. If *this has an associated mutex and has acquired ownership of it, the mutex is unlocked.