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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 $
40 .Nd send signal to a process
47 .Fn kill "pid_t pid" "int sig"
51 function sends the signal given by
56 process or a group of processes.
58 may be one of the signals specified in
60 or it may be 0, in which case
61 error checking is performed but no
62 signal is actually sent.
63 This can be used to check the validity of
66 For a process to have permission to send a signal to a process designated
69 the real or effective user ID of the receiving process must match
70 that of the sending process or the user must have appropriate privileges
71 (such as given by a set-user-ID program or the user is the super-user).
72 A single exception is the signal SIGCONT, which may always be sent
73 to any descendant of the current process.
75 .It \&If Fa pid No \&is greater than zero :
77 is sent to the process whose ID is equal to
79 .It \&If Fa pid No \&is zero :
81 is sent to all processes whose group ID is equal
82 to the process group ID of the sender, and for which the
83 process has permission;
86 .It \&If Fa pid No \&is -1 :
87 If the user has super-user privileges,
88 the signal is sent to all processes excluding
96 and the process sending the signal.
97 If the user is not the super user, the signal is sent to all processes
98 with the same uid as the user excluding the process sending the signal.
99 No error is returned if any process could be signaled.
102 For compatibility with System V,
103 if the process number is negative but not -1,
104 the signal is sent to all processes whose process group ID
105 is equal to the absolute value of the process number.
112 will fail and no signal will be sent if:
116 is not a valid signal number.
118 No process can be found corresponding to that specified by
121 The process id was given as 0
122 but the sending process does not have a process group.
124 The sending process is not the super-user and its effective
125 user id does not match the effective user-id of the receiving process.
126 When signaling a process group, this error is returned if any members
127 of the group could not be signaled.
139 function call is expected to conform to
144 function call appeared in