KILL(2) System Calls Manual KILL(2)
kill - send signal to a process
Kill sends the signal sig to the process specified by the process num-
ber in r0. See signal(2) for a list of signals.
The sending and receiving processes must have the same effective user
ID, otherwise this call is restricted to the super-user.
If the process number is 0, the signal is sent to all other processes
in the sender's process group; see tty(4).
If the process number is -1, and the user is the super-user, the signal
is broadcast universally except to processes 0 and 1, the scheduler and
initialization processes, see init(8).
Processes may send signals to themselves.
Zero is returned if the process is killed; -1 is returned if the
process does not have the same effective user ID and the user is not
super-user, or if the process does not exist.
(kill = 37.)
(process number in r0)
sys kill; sig