CopperSpice API  1.7.2
QWriteLocker Class Reference

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

Public Methods

 QWriteLocker (QReadWriteLock *readWriteLock)
 
 ~QWriteLocker ()
 
QReadWriteLockreadWriteLock () const
 
void relock ()
 
void unlock ()
 

Detailed Description

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

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

Here is an example that uses QWriteLocker to lock and unlock a read-write lock for writing:

void writeData(const QByteArray &data)
{
QWriteLocker locker(&lock);
...
}

It is equivalent to the following code:

void writeData(const QByteArray &data)
{
lock.lockForWrite();
...
lock.unlock();
}

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

See also
QReadLocker, QReadWriteLock

Constructor & Destructor Documentation

QWriteLocker::QWriteLocker ( QReadWriteLock readWriteLock)
inline

Constructs a QWriteLocker and locks lock for writing. The lock will be unlocked when the QWriteLocker is destroyed. If lock is zero, QWriteLocker does nothing.

See also
QReadWriteLock::lockForWrite()
QWriteLocker::~QWriteLocker ( )
inline

Destroys the QWriteLocker and unlocks the lock that was passed to the constructor.

See also
QReadWriteLock::unlock()

Method Documentation

QReadWriteLock * QWriteLocker::readWriteLock ( ) const
inline

Returns a pointer to the read-write lock that was passed to the constructor.

void QWriteLocker::relock ( )
inline

Relocks an unlocked lock.

See also
unlock()
void QWriteLocker::unlock ( )
inline

Unlocks the lock associated with this locker.

See also
QReadWriteLock::unlock()