QReadLocker Class

The QReadLocker class is a convenience class that simplifies locking and unlocking read-write locks for read access. More...

Header: #include <QReadLocker>
qmake: QT += core

Note: All functions in this class are thread-safe.

Public Functions

QReadLocker(QReadWriteLock *readWriteLock)
~QReadLocker()
QReadWriteLock *readWriteLock() const
void relock()
void unlock()

Detailed Description

The QReadLocker class is a convenience class that simplifies locking and unlocking read-write locks for read access.

The purpose of QReadLocker (and QWriteLocker) is to simplify QReadWriteLock locking and unlocking. Locking and unlocking statements or in exception handling code is error-prone and difficult to debug. QReadLocker can be used in such situations to ensure that the state of the lock is always well-defined.

Here's an example that uses QReadLocker to lock and unlock a read-write lock for reading:


  QReadWriteLock lock;

  QByteArray readData()
  {
      QReadLocker locker(&lock);
      ...
      return data;
  }

It is equivalent to the following code:


  QReadWriteLock lock;

  QByteArray readData()
  {
      lock.lockForRead();
      ...
      lock.unlock();
      return data;
  }

The QMutexLocker documentation shows examples where the use of a locker object greatly simplifies programming.

See also QWriteLocker and QReadWriteLock.

Member Function Documentation

QReadLocker::QReadLocker(QReadWriteLock *readWriteLock)

Default constructs an instance of QReadLocker.

QReadLocker::~QReadLocker()

Destroys the instance of QReadLocker.

QReadWriteLock *QReadLocker::readWriteLock() const

void QReadLocker::relock()

void QReadLocker::unlock()