How to block your App to Nap (macOS AppNap)

[claudiofantacci]

AppNap is macOS feature introduced with Yosemite (10.9) to improve battery life and system responsiveness. To achieve this goal, every application that is deemed to be on the background is slowed down. As a mac user, you probably have never cared too much about it: your mac runs smooth and the battery last long. As a developer, however, you should be worried about this feature and, in particular, how the OS deems an app running in the background and, I quote

an app might nap when it's hidden behind other windows, or when it's open in a space that you aren't currently viewing.

If you reached this post, you probably noticed some strange performance issues/variations of your application (may it a console or a window application) and noticed something like this in the AppNap column of Activity Montior

If you happen to be here by chance, well, your application may be slowed down by your system and you weren't aware of it.

macOS provides interfaces to disable AppNap on application basis and YARP, after robotology/yarp#1354, is provided with a feature to just do it!

To disable AppNap you just need the following 3 lines of code to your YARP app:

#include <yarp/os/Os.h>

int main(int argc, char* argv[])
{
    yarp::os::setEnergySavingModeState(false);

    [Your magic source code here]

    yarp::os::setEnergySavingModeState(true);

    return EXIT_SUCCESS;
}