QWriteLocker

Synopsis

Functions

• def __enter__ ()
• def __exit__ (arg__1, arg__2, arg__3)
• def readWriteLock ()
• def relock ()
• def unlock ()

Detailed Description

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

The purpose of PySide.QtCore.QWriteLocker (and PySide.QtCore.QReadLocker is to simplify PySide.QtCore.QReadWriteLock locking and unlocking. Locking and unlocking statements or in exception handling code is error-prone and difficult to debug. PySide.QtCore.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 PySide.QtCore.QWriteLocker to lock and unlock a read-write lock for writing:

lock = QReadWriteLock()

def writeData(data):
    locker = QWriteLocker(lock)
    # ...

It is equivalent to the following code:

lock = QReadWriteLock()

def writeData(data):
    locker.lockForWrite()
    # ...
    locker.unlock()

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

See also

PySide.QtCore.QReadLocker PySide.QtCore.QReadWriteLock

class PySide.QtCore.QWriteLocker(readWriteLock)

Parameters:readWriteLock – PySide.QtCore.QReadWriteLock

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

See also

QReadWriteLock.lockForWrite()

PySide.QtCore.QWriteLocker.__enter__()

PySide.QtCore.QWriteLocker.__exit__(arg__1, arg__2, arg__3)

Parameters:

• arg__1 – PyObject
• arg__2 – PyObject
• arg__3 – PyObject

PySide.QtCore.QWriteLocker.readWriteLock()

Return type:PySide.QtCore.QReadWriteLock

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

PySide.QtCore.QWriteLocker.relock()

Relocks an unlocked lock.

See also

PySide.QtCore.QWriteLocker.unlock()

PySide.QtCore.QWriteLocker.unlock()

Unlocks the lock associated with this locker.

See also

QReadWriteLock.unlock()