Struct qt_core::QReadLocker

#[repr(C)]pub struct QReadLocker { /* fields omitted */ }

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

C++ class: QReadLocker.

C++ documentation:

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

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:

QReadWriteLock lock;
QByteArray readData()
{
      QReadLocker locker(&lock);
      ...
      return data;
}

It is equivalent to the following code:

QReadWriteLock lock;
QByteArray readData()
{
      lock.lockForRead();
      ...
      lock.unlock();
      return data;
}

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

Methods

impl QReadLocker

pub unsafe fn new(
    read_write_lock: impl CastInto<Ptr<QReadWriteLock>>
) -> CppBox<QReadLocker>

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.

Calls C++ function: [constructor] void QReadLocker::QReadLocker(QReadWriteLock* readWriteLock).

C++ documentation:

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 QReadWriteLock::lockForRead().

pub unsafe fn read_write_lock(&self) -> Ptr<QReadWriteLock>

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

Calls C++ function: QReadWriteLock* QReadLocker::readWriteLock() const.

C++ documentation:

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

pub unsafe fn relock(&self)

Relocks an unlocked lock.

Calls C++ function: void QReadLocker::relock().

C++ documentation:

Relocks an unlocked lock.

See also unlock().

pub unsafe fn unlock(&self)

Unlocks the lock associated with this locker.

Calls C++ function: void QReadLocker::unlock().

C++ documentation:

Unlocks the lock associated with this locker.

See also QReadWriteLock::unlock().

Trait Implementations

impl CppDeletable for QReadLocker

unsafe fn delete(&self)

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

Calls C++ function: [destructor] void QReadLocker::~QReadLocker().

C++ documentation:

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

See also QReadWriteLock::unlock().