.\" Hey Emacs! This file is -*- nroff -*- source. .\" .\" Copyright (c) 1992 Drew Eckhardt (drew@cs.colorado.edu), March 28, 1992 .\" .\" Permission is granted to make and distribute verbatim copies of this .\" manual provided the copyright notice and this permission notice are .\" preserved on all copies. .\" .\" Permission is granted to copy and distribute modified versions of this .\" manual under the conditions for verbatim copying, provided that the .\" entire resulting derived work is distributed under the terms of a .\" permission notice identical to this one .\" .\" Since the Linux kernel and libraries are constantly changing, this .\" manual page may be incorrect or out-of-date. The author(s) assume no .\" responsibility for errors or omissions, or for damages resulting from .\" the use of the information contained herein. The author(s) may not .\" have taken the same level of care in the production of this manual, .\" which is licensed free of charge, as they might when working .\" professionally. .\" .\" Formatted or processed versions of this manual, if unaccompanied by .\" the source, must acknowledge the copyright and authors of this work. .\" .\" Modified by Michael Haardt (u31b3hs@pool.informatik.rwth-aachen.de) .\" Modified by Thomas Koenig (ig25@rz.uni-karlsruhe.de) .\" Modified Fri Jul 23 21:51:36 1993 by Rik Faith (faith@cs.unc.edu) .\" Modified Sun Jul 25 10:53:24 1993 by Rik Faith (faith@cs.unc.edu) .\" Modified Wed Nov 01 18:56:43 1995 by Michael Haardt .\" (michael@cantor.informatik.rwth-aachen.de) .\" Modified Sun Apr 14 17:04:32 1996 by Andries Brouwer (aeb@cwi.nl) .\" [added some polishing contributed by Mike Battersby (mib@deakin.edu.au)] .\" Modified Sun Jul 21 21:25:26 1996 by Andries Brouwer (aeb@cwi.nl) .\" .TH KILL 2 "November 1, 1995" "Linux" "Linux Programmer's Manual" .SH NAME kill \- send signal to a process .SH SYNOPSIS .nf .B #include .br .B #include .sp .BI "int kill(pid_t " pid ", int " sig ); .fi .SH DESCRIPTION The .B kill system call can be used to send any signal to any process group or process. .PP If \fIpid\fP is positive, then signal \fIsig\fP is sent to \fIpid\fP. In this case, 0 is returned on success, or a negative value on error. .PP If \fIpid\fP equals \-1, then \fIsig\fP 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. .PP If \fIpid\fP is less than \-1, then \fIsig\fP is sent to every process in the process group \fI\-pid\fP. In this case, the number of processes the signal was sent to is returned, or a negative value for failure. .SH "RETURN VALUE" On success, zero is returned. On error, \-1 is returned, and .I errno is set appropriately. .SH ERRORS .TP .B EINVAL An invalid signal is sent. .TP .B 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 \fBwait()\fPed for. .TP .B EPERM The effective userid of the process calling .B kill() is not equal to the effective userid of \fIpid\fP, unless the superuser called \fBkill()\fP. .SH "BUGS" It is impossible to send a signal to task number one, the init process, for which it has not installed a signal handler. This is done to assure the system is not brought down accidentally. .SH "CONFORMING TO" SVID, AT&T, POSIX.1, X/OPEN, BSD 4.3 .SH "SEE ALSO" .BR _exit "(2), " exit "(2), " signal "(2), " signal (7)