Contents

rw_mutex

Note

To enable this feature, define the TBB_PREVIEW_MUTEXES macro to 1.

Description

A rw_mutex is a class that models the ReaderWriterMutex requirement, using adaptive approach: the combination of spinlock and waiting on system primitives. The rw_mutex class satisfies all of the shared mutex requirements described in the [thread.sharedmutex.requirements] section of the ISO C++ standard. The rw_mutex class is unfair reader-writer lock with writer-preference.

API

Synopsis

namespace oneapi {
    namespace tbb {
        class rw_mutex {
        public:
            rw_mutex() noexcept;
            ~rw_mutex();

            rw_mutex(const rw_mutex&) = delete;
            rw_mutex& operator=(const rw_mutex&) = delete;

            class scoped_lock;

            // exclusive ownership
            void lock();
            bool try_lock();
            void unlock();

            // shared ownership
            void lock_shared();
            bool try_lock_shared();
            void unlock_shared();

            static constexpr bool is_rw_mutex = true;
            static constexpr bool is_recursive_mutex = false;
            static constexpr bool is_fair_mutex = false;
        };
    }
}

Member classes

class scoped_lock

The corresponding scoped-lock class. See the ReaderWriterMutex requirement.

Member functions

rw_mutex()

Constructs unlocked rw_mutex.

~rw_mutex()

Destroys unlocked rw_mutex.

void lock()

Acquires a lock. It uses adaptive logic for waiting: it blocks after particular time period of busy wait.

bool try_lock()

Tries to acquire a lock (non-blocking) on write. Returns true if succeeded; false otherwise.

void unlock()

Releases the write lock held by the current thread.

void lock_shared()

Acquires a lock on read. It uses adaptive logic for waiting: it blocks after particular time period of busy wait.

bool try_lock_shared()

Tries to acquire the lock (non-blocking) on read. Returns true if succeeded; false otherwise.

void unlock_shared()

Releases the read lock held by the current thread.