I'm thinking through alerting stuff, and decided that, if my screen is locked, I'm not there so I should push the alerts to my phone. But, I cannot currently tell if the screen is locked. I could put something together with Perl and xscreensaver-command -watch, but I'd rather not have to make sure I have that process always running and all. That seems too heavy.
Is there something I'm missing? This seems fairly obvious.