QScopeGuard Class

Related Non-Members

QScopeGuard<F> qScopeGuard(F f)

The qScopeGuard function can be used to call a function at the end of the scope.

QScopeGuard<F> is a class of which the sole purpose is to run the function f in its destructor. This is useful for guaranteeing your cleanup code is executed, whether the function is exited normally, exited early by a return statement, or exited by an exception.

If F is a lambda then you cannot instantiate the template directly, therefore the qScopeGuard() helper is provided and QScopeGuard<F> is made a private implementation detail.

Example usage is as follows:

void myComplexCodeWithMultipleReturnPoints(int v)
{
    // The lambda will be executed right before your function returns
    auto cleanup = qScopeGuard([] { code you want executed goes HERE; });

    if (v == -1)
        return;

    int v2 = code_that_might_throw_exceptions();

    if (v2 == -1)
        return;

    (...)
}

Note: Exceptions are not supported. The callable shouldn't throw when executed, copied or moved.

See also QScopedValueRollback.