This question relates to Android versions pre-Lollipop. For Lollipop API, check related question:
I would like to know how to turn on / off the system Alarm icon in the status bar as shown in this image:
From what I understand about the system, and what I've read in the past, it is controlled by the built in system alarm clock app. And 3rd party apps have no control over it on an unrooted device. There is no reason we should be able to control it.
However, Timely v1.2.7 controls this icon on my unrooted Galaxy Nexus v4.2.1, & Nexus 5 v4.4.2. So it is possible.
I wonder what the technique is to do this on an unrooted device. I suspect a hack or undocumented code but still interested if anyone can shed some light.