I posed this briefly in the ChatterBox then realized it's probably more than just a Yes/No question.

My SysAdmin suggested we add a signal handler or two to a pair of daemons that we run as schedulers for our web application. These handlers would catch a signal from the web application and produce a report on "What's happening" suitable for display on a web page. We're thinking we'd like to have one suitable for public viewing, and a messier one for internal viewing. (I've already thought of clever features such as the scheduler invalidating the reports as soon as it does something that would affect the report, and not generating the report if nothing has changed since the last report was generated.)

Having had a quick look at /usr/include/asm/signal.h, I could grab two of SIGUSR1, SIGUSR2 and SIGPOLL .. or I could make up two of my own signals somewhere else (above SIGRTMAX?)

Having written a few interrupt service request handlers in my time I have a good idea about what's going on .. I'd just like some guidance on which signals might be good ones to use.