class QReadLocker#

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

Synopsis#

Methods#

Note

This documentation may contain snippets that were automatically translated from C++ to Python. We always welcome contributions to the snippet translation. If you see an issue with the translation, you can also let us know by creating a ticket on https:/bugreports.qt.io/projects/PYSIDE

Detailed Description#

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

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:

lock = QReadWriteLock()
def readData():

    locker = QReadLocker(lock)
    ...
    return data

It is equivalent to the following code:

lock = QReadWriteLock()
def readData():

    lock.lockForRead()
    ...
    lock.unlock()
    return data

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

__init__(readWriteLock)#
Parameters:

readWriteLock – QReadWriteLock

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

lockForRead()

__enter__()#
Return type:

QReadLocker

__exit__(arg__1, arg__2, arg__3)#
Parameters:

  • arg__1 – object

  • arg__2 – object

  • arg__3 – object

readWriteLock()#
Return type:

QReadWriteLock

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

relock()#

Relocks an unlocked lock.

See also

unlock()

unlock()#

Unlocks the lock associated with this locker.

See also

unlock()