How to call multiple functions when QTimer expires?

Question

I want to be able to call multiple functions/ methods when a timer timeouts, without creating a new slot method that calls the desired methods (see code).

int foo;
int bar;

// …

private slots:
    inline void foo_func() { /*…*/ }
    inline void bar_func() { /*…*/ }
    inline void combination_of_multiple_func()
    {
        foo_func();
        bar_func();
    }

// …


// somewhere in a method:
if (foo == bar)
{
    // Schedule … every foo or bar milliseconds
    QTimer *timer = new QTimer(this);
    connect(timer, SIGNAL(timeout()), this, SLOT(combination_of_multiple_func()));
    timer->start(foo);
}
else
{
    // Schedule … every foo milliseconds
    QTimer *fooTimer = new QTimer(this);
    connect(fooTimer, SIGNAL(timeout()), this, SLOT(foo_func()));
    fooTimer->start(foo);

    // Schedule … every bar milliseconds
    QTimer *barTimer = new QTimer(this);
    connect(barTimer, SIGNAL(timeout()), this, SLOT(bar_func()));
    barTimer->start(bar);
}

Is there a better solution?

Answer 1

First, you should use Qt's new signal and slot syntax if you can.

I can think of 2 ways I would solve this problem:

Use a lambda

if (foo == bar)
{
    // Schedule … every foo or bar milliseconds
    QTimer *timer = new QTimer(this);
    connect(timer, &QTimer::timeout, this, [] { foo_func(); bar_func(); } );
    timer->start(foo);
}

Ignore it

Just make 2 timers every time. The overhead is probably not enough to actually care about.