KILL(2)KILL(2)NAMEkill - send signal to a process
SYNOPSIS
#include <sys/types.h>
#include <signal.h>
int kill(pid_t pid, int sig)
DESCRIPTION
Kill sends the signal sig to a process, specified by the process number
pid. Sig may be one of the signals specified in sigaction(2), or it
may be 0, in which case error checking is performed but no signal is
actually sent. This can be used to check the validity of pid.
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 processes in the
sender's process group.
If the process number is -1 and the user is the super-user, the signal
is broadcast universally except to init and the process sending the
signal. If the process number is -1 and the user is not the super-
user, the signal is broadcast universally to all processes with the
same uid as the user except the process sending the signal. No error
is returned if any process could be signaled.
If the process number is negative but not -1, the signal is sent to all
processes whose process group ID is equal to the absolute value of the
process number.
Processes may send signals to themselves.
RETURN VALUE
Upon successful completion, a value of 0 is returned. Otherwise, a
value of -1 is returned and errno is set to indicate the error.
ERRORS
Kill will fail and no signal will be sent if any of the following
occur:
[EINVAL] Sig is not a valid signal number.
[ESRCH] No process can be found corresponding to that specified
by pid.
[ESRCH] The process id was given as 0 but the sending process
does not have a process group.
[EPERM] The sending process is not the super-user and its effec‐
tive user id does not match the effective user-id of the
receiving process. When signaling a process group, this
error was returned if any members of the group could not
be signaled.
SEE ALSOgetpid(2), getpgrp(2), sigaction(2), raise(3).
4th Berkeley Distribution May 14, 1986 KILL(2)
