33 Concurrency support library [thread]

33.6 Mutual exclusion [thread.mutex]

33.6.5 Locks [thread.lock]

33.6.5.2 Class template lock_guard [thread.lock.guard]

namespace std { template<class Mutex> class lock_guard { public: using mutex_type = Mutex; explicit lock_guard(mutex_type& m); lock_guard(mutex_type& m, adopt_lock_t); ~lock_guard(); lock_guard(const lock_guard&) = delete; lock_guard& operator=(const lock_guard&) = delete; private: mutex_type& pm; // exposition only }; }

An object of type lock_guard controls the ownership of a lockable object within a scope.

A lock_guard object maintains ownership of a lockable object throughout the lock_guard object's lifetime .

The behavior of a program is undefined if the lockable object referenced by pm does not exist for the entire lifetime of the lock_guard object.

The supplied Mutex type shall meet the Cpp17BasicLockable requirements ([thread.req.lockable.basic]).

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explicit lock_guard(mutex_type& m);

Effects: Initializes pm with m.

Calls m.lock().

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lock_guard(mutex_type& m, adopt_lock_t);

Preconditions: The calling thread holds a non-shared lock on m.

Effects: Initializes pm with m.

Throws: Nothing.

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~lock_guard();

Effects: Equivalent to: pm.unlock()