In most cases if you want to handle a signal in your application you write a simple signal handler like:
void handler (int sig)
and use the signal(2) system function to run it when a signal is delivered to the process. This is the simplest case, but signals are more interesting than that! Information contained in this article is useful for example when you are writing a daemon and must handle interrupting your program properly without interrupting the current operation or the whole program.