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32 .\" @(#)kill.2 8.3 (Berkeley) 4/19/94
33 .\" $FreeBSD: src/lib/libc/sys/kill.2,v 1.10.2.7 2001/12/14 18:34:01 ru Exp $
34 .\" $DragonFly: src/lib/libc/sys/kill.2,v 1.2 2003/06/17 04:26:47 dillon Exp $
41 .Nd send signal to a process
48 .Fn kill "pid_t pid" "int sig"
52 function sends the signal given by
57 process or a group of processes.
59 may be one of the signals specified in
61 or it may be 0, in which case
62 error checking is performed but no
63 signal is actually sent.
64 This can be used to check the validity of
67 For a process to have permission to send a signal to a process designated
70 the real or effective user ID of the receiving process must match
71 that of the sending process or the user must have appropriate privileges
72 (such as given by a set-user-ID program or the user is the super-user).
73 A single exception is the signal SIGCONT, which may always be sent
74 to any descendant of the current process.
76 .It \&If Fa pid No \&is greater than zero :
78 is sent to the process whose ID is equal to
80 .It \&If Fa pid No \&is zero :
82 is sent to all processes whose group ID is equal
83 to the process group ID of the sender, and for which the
84 process has permission;
87 .It \&If Fa pid No \&is -1 :
88 If the user has super-user privileges,
89 the signal is sent to all processes excluding
97 and the process sending the signal.
98 If the user is not the super user, the signal is sent to all processes
99 with the same uid as the user excluding the process sending the signal.
100 No error is returned if any process could be signaled.
103 For compatibility with System V,
104 if the process number is negative but not -1,
105 the signal is sent to all processes whose process group ID
106 is equal to the absolute value of the process number.
113 will fail and no signal will be sent if:
117 is not a valid signal number.
119 No process can be found corresponding to that specified by
122 The process id was given as 0
123 but the sending process does not have a process group.
125 The sending process is not the super-user and its effective
126 user id does not match the effective user-id of the receiving process.
127 When signaling a process group, this error is returned if any members
128 of the group could not be signaled.
140 function call is expected to conform to
145 function call appeared in