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()
{
locker.lockForRead();
...
locker.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 * lock )
Constructs a QReadLocker and locks lock for reading. The lock will be unlocked when the QReadLocker is destroyed. If lock is zero, QReadLocker does nothing.
See also QReadWriteLock::lockForRead().
QReadLocker::~QReadLocker ()
Destroys the QReadLocker and unlocks the lock that was passed to the constructor.
See also QReadWriteLock::unlock().
QReadWriteLock * QReadLocker::readWriteLock () const
Returns a pointer to the read-write lock that was passed to the constructor.
void QReadLocker::relock ()
Relocks an unlocked lock.
See also unlock().
void QReadLocker::unlock ()
Unlocks the lock associated with this locker.
See also QReadWriteLock::unlock().
