man2/killpg.2

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  32 .\"     @(#)killpg.2    6.5 (Berkeley) 3/10/91
  33 .\"
  34 .\" Modified Fri Jul 23 21:55:01 1993 by Rik Faith <faith@cs.unc.edu>
  35 .\" Modified Tue Oct 22 08:11:14 EDT 1996 by Eric S. Raymond <esr@thyrsus.com>
  36 .\" Modified 2004-06-16 by Michael Kerrisk <mtk-manpages@gmx.net>
  37 .\"     Added notes on CAP_KILL
  38 .\" Modified 2004-06-21 by aeb
  39 .\"
  40 .TH KILLPG 2 2004-06-21 "Linux" "Linux Programmer's Manual"
  41 .SH NAME
  42 killpg \- send signal to a process group
  43 .SH SYNOPSIS
  44 .B #include <signal.h>
  45 .sp
  46 .BI "int killpg(int " pgrp ", int " sig );
  47 .SH DESCRIPTION
  48 .BR killpg ()
  49 sends the signal
  50 .I sig
  51 to the process group
  52 .IR pgrp .
  53 See
  54 .BR signal (7)
  55 for a list of signals.
  56 If
  57 .I pgrp
  58 is 0,
  59 .BR killpg ()
  60 sends the signal to the sending process's process group.
  61
  62 (POSIX says: If
  63 .I pgrp
  64 is less than or equal to 1, the behaviour is undefined.)
  65
  66 For a process to have permission to send a signal
  67 it must either be privileged (under Linux: have the
  68 .B CAP_KILL
  69 capability), or the real or effective
  70 user ID of the sending process must equal the real or
  71 saved set-user-ID of the target process.
  72 In the case of SIGCONT it suffices when the sending and receiving
  73 processes belong to the same session.
  74 .SH "RETURN VALUE"
  75 On success, zero is returned.
  76 On error, \-1 is returned, and
  77 .I errno
  78 is set appropriately.
  79 .SH ERRORS
  80 .TP
  81 .B EINVAL
  82 .I Sig
  83 is not a valid signal number.
  84 .TP
  85 .B EPERM
  86 The process does not have permission to send the signal
  87 to any of the target processes.
  88 .TP
  89 .B ESRCH
  90 No process can be found in the process group specified by
  91 .IR pgrp .
  92 .TP
  93 .B ESRCH
  94 The process group was given as 0 but the sending process does not
  95 have a process group.
  96 .SH "CONFORMING TO"
  97 SVr4, 4.4BSD (The
  98 .BR killpg ()
  99 function call first appeared in 4BSD), POSIX.1-2001.
 100 .SH NOTES
 101 There are various differences between the permission checking
 102 in BSD-type systems and System V-type systems.
 103 See the POSIX rationale for
 104 .BR kill (2).
 105 A difference not mentioned by POSIX concerns the return
 106 value EPERM: BSD documents that no signal is sent and EPERM returned
 107 when the permission check failed for at least one target process,
 108 while POSIX documents EPERM only when the permission check failed
 109 for all target processes.
 110 .SH "SEE ALSO"
 111 .BR getpgrp (2),
 112 .BR kill (2),
 113 .BR signal (2),
 114 .BR capabilities (7)