QAtomicScopedValueRollback Class

template <typename T> class QAtomicScopedValueRollback

The QAtomicScopedValueRollback class resets an atomic variable to its previous value on destruction. More…

List of all members, including inherited members

Public Functions

Detailed Description

It is the counterpart of QScopedValueRollback for std::atomic variables. The object stores the variable's value when it is created, and writes it back when it goes out of scope, unless commit() was called:

std::atomic<int> state = 0;
{
    QAtomicScopedValueRollback<int> rollback(state, 1);
    // state is 1 here; it is 0 again after the block
}

See also QScopedValueRollback.

Differences from Qt

Member Function Documentation

[explicit] QAtomicScopedValueRollback::QAtomicScopedValueRollback(std::atomic<T> &var, std::memory_order mo = std::memory_order_seq_cst)

Constructs an object that restores var to its current value when it is destroyed. The value is read and written with the memory order mo.

QAtomicScopedValueRollback::QAtomicScopedValueRollback(std::atomic<T> &var, T value, std::memory_order mo = std::memory_order_seq_cst)

This is an overloaded function.

Stores value in var and restores the previous value when the object is destroyed.

QAtomicScopedValueRollback::~QAtomicScopedValueRollback()

Restores the saved value, unless commit() was called.

void QAtomicScopedValueRollback::commit()

Makes the variable keep its current value: nothing is restored when the object is destroyed.