Let's not forget the system call
! (jesus, I have to stop noding C functions...)
int kill( pid_t pid, int sig );
in sys/types.h, and the function
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