QSemaphoreReleaser Class

The QSemaphoreReleaser class provides exception-safe deferral of a QSemaphore::release() call. More…

List of all members, including inherited members

Public Functions

Detailed Description

A QSemaphoreReleaser releases a number of resources on a QSemaphore when it is destroyed, unless cancel() was called first.

QSemaphore sem;

void work()
{
    QSemaphoreReleaser releaser(sem);
    // the semaphore is released when this function returns
}

See also QSemaphore.

Differences from Qt

Member Function Documentation

QSemaphoreReleaser::QSemaphoreReleaser()

Constructs a releaser that does nothing.

[explicit] QSemaphoreReleaser::QSemaphoreReleaser(QSemaphore &s, int n = 1)

Constructs a releaser that releases n resources on s when it is destroyed.

[explicit] QSemaphoreReleaser::QSemaphoreReleaser(QSemaphore *s, int n = 1)

This is an overloaded function.

Constructs a releaser that releases n resources on s when it is destroyed. If s is nullptr, the releaser does nothing.

QSemaphoreReleaser::QSemaphoreReleaser(QSemaphoreReleaser &&other)

Move-constructs a releaser from other, which no longer releases anything afterwards.

QSemaphoreReleaser::~QSemaphoreReleaser()

Destroys the releaser and releases the resources on the semaphore, unless it was cancelled.

QSemaphore * QSemaphoreReleaser::cancel()

Cancels the pending release and returns the semaphore the releaser was operating on, or nullptr if there was none. The destructor then does nothing.

QSemaphoreReleaser & QSemaphoreReleaser::operator=(QSemaphoreReleaser &&other)

Move-assigns other to this releaser and returns a reference to it. A release pending on this releaser happens first.

QSemaphore * QSemaphoreReleaser::semaphore() const

Returns the semaphore the releaser operates on, or nullptr if there is none or the release was cancelled.

See also cancel().

void QSemaphoreReleaser::swap(QSemaphoreReleaser &other)

Swaps the semaphore and count of this releaser with those of other.