KILL(2) Linux Programmer's Manual KILL(2)
NAME
kill - send signal to a process
SYNOPSIS
#include <sys/types.h>
#include <signal.h>
int kill(pid_t pid, int sig);
DESCRIPTION
The kill system call can be used to send any signal to any
process group or process.
If pid is positive, then signal sig is sent to pid. In
this case, 0 is returned on success, or a negative value
on error.
If pid equals -1, then sig is sent to every process except
for the first one, from higher numbers in the proc table
to lower. In this case, 0 is returned on success, or the
error condition resulting from signalling the last process
is returned.
If pid is less than -1, then sig is sent to every process
in the process group -pid. In this case, the number of
processes the signal was sent to is returned, or a nega-
tive value for failure.
RETURN VALUE
On success, zero is returned. On error, -1 is returned,
and errno is set appropriately.
ERRORS
EINVAL An invalid signal is sent.
ESRCH The pid or process group does not exist. Note that
an existing process might be a zombie, a process
which already committed termination, but has not
yet been wait()ed for.
EPERM The effective userid of the process calling kill()
is not equal to the effective userid of pid, unless
the superuser called kill().
BUGS
It is impossible to send a signal to task number one, the
init process, for which it has not installed a signal han-
dler. This is done to assure the system is not brought
down accidentally.
CONFORMING TO
SVID, AT&T, POSIX.1, X/OPEN, BSD 4.3
Linux November 1, 1995 1
KILL(2) Linux Programmer's Manual KILL(2)
SEE ALSO
_exit(2), exit(2), signal(2), signal(7)
Linux November 1, 1995 2