Let's not forget the
system call!
(jesus, I have to stop noding C functions...)
int kill( pid_t pid, int sig );
pid_t is
defined in sys/types.h, and the
function is
prototyped in signal.h.
The pid arg can have special meaning. If it's zero, the current process and all children are sent the signal. If it's -1, all processes are sent it, except pid 1. Otherwise, it specifies a pid.
As for the
second arg, see
unix signals.