How to programmatically prevent linux computer from sleeping or turning on screensaver?

Question

While developing a small cross-platform game on C++, I got stuck with following issue: when players are playing with a USB gamepad without touching a keyboard or mouse, the comp

Answer 1

I'm using QTDBUS using that

QDBusConnection bus = QDBusConnection::sessionBus();
if(bus.isConnected())
{
    QString services[MAX_SERVICES] = {
        "org.freedesktop.ScreenSaver",
        "org.gnome.SessionManager"
    };
    QString paths[MAX_SERVICES] = {
        "/org/freedesktop/ScreenSaver",
        "/org/gnome/SessionManager"
    };

    for(int i = 0; i < MAX_SERVICES ; i++)
    {        
        QDBusInterface screenSaverInterface(
            services[i], paths[i],services[i], bus, this);
        if (!screenSaverInterface.isValid())
            continue;       

        QDBusReply<uint> reply = screenSaverInterface.call(
            "Inhibit", "YOUR_APP_NAME", "REASON");
        if (reply.isValid())
        {
            cookieID = reply.value();
            qDebug()<<"succesful"
        } else {   
            QDBusError error =reply.error();
            qDebug()<<error.message()<<error.name();   
        }
    }
}

Answer 2

From a quick look at how mplayer and SDL do it, there are two things you can do to prevent the screensaver from firing up:

• Disable it for the duration of the program:
  • Using XScreenSaverSuspend
  • Using DBus, calling org.freedesktop.ScreenSaver.Inhibit
• Ping it periodically:
  • Using XResetScreenSaver
  • Using DBus, calling org.freedesktop.ScreenSaver.SimulateUserActivity

Answer 3

As far as I can tell, things with xdg in the name are the way to go for cross-desktop-environment functionality. There appears to be a commandline utility called xdg-screensaver. It seems to have a bunch of screensavers hardwired and then fall back to xset s off/xset s default, so you might want to just call it when it's installed, or fall back to copying part of its logic when it's not...