QWriteLocker Class
The QWriteLocker class is a convenience class that simplifies locking and unlocking read-write locks for write access. More...
Header: | #include <QWriteLocker> |
qmake: | QT += core |
Note: All functions in this class are thread-safe.
Public Functions
QWriteLocker(QReadWriteLock *lock) | |
~QWriteLocker() | |
QReadWriteLock * | readWriteLock() 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's an example that uses QWriteLocker to lock and unlock a read-write lock for writing:
QReadWriteLock lock; void writeData(const QByteArray &data) { QWriteLocker locker(&lock); ... }
It is equivalent to the following code:
QReadWriteLock lock; 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 and QReadWriteLock.
Member Function Documentation
QWriteLocker::QWriteLocker(QReadWriteLock *lock)
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()
Destroys the QWriteLocker and unlocks the lock that was passed to the constructor.
See also QReadWriteLock::unlock().
QReadWriteLock *QWriteLocker::readWriteLock() const
Returns a pointer to the read-write lock that was passed to the constructor.
void QWriteLocker::relock()
Relocks an unlocked lock.
See also unlock().
void QWriteLocker::unlock()
Unlocks the lock associated with this locker.
See also QReadWriteLock::unlock().
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Licensed under the GNU Free Documentation License, Version 1.3.
https://doc.qt.io/qt-5.9/qwritelocker.html