class QReadLocker

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

Synopsis

Methods

Note

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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()