1kill(2) System Calls kill(2)
2
6 kill - send a signal to a process or a group of processes
7
9 #include <sys/types.h>
10 #include <signal.h>
11 int kill(pid_t pid, int sig);
13
16 The kill() function sends a signal to a process or a group of pro‐
17 cesses. The process or group of processes to which the signal is to be
18 sent is specified by pid. The signal that is to be sent is specified by
19 sig and is either one from the list given in signal (see sig‐
20 nal.h(3HEAD)), or 0. If sig is 0 (the null signal), error checking is
21 performed but no signal is actually sent. This can be used to check the
22 validity of pid.
23 The real or effective user ID of the sending process must match the
26 real or saved (from one of functions in the exec(2) family) user ID of
27 the receiving process, unless the privilege {PRIV_PROC_OWNER} is
28 asserted in the effective set of the sending process (see Intro(2)), or
29 sig is SIGCONT and the sending process has the same session ID as the
30 receiving process. A process needs the basic privilege {PRIV_PROC_SES‐
31 SION} to send signals to a process with a different session ID. See
32 privileges(5).
33 If pid is greater than 0, sig will be sent to the process whose process
36 ID is equal to pid.
37 If pid is negative but not (pid_t)−1, sig will be sent to all processes
40 whose process group ID is equal to the absolute value of pid and for
41 which the process has permission to send a signal.
42 If pid is 0, sig will be sent to all processes excluding special pro‐
45 cesses (see Intro(2)) whose process group ID is equal to the process
46 group ID of the sender.
47 If pid is (pid_t)−1 and the {PRIV_PROC_OWNER} privilege is not asserted
50 in the effective set of the sending process, sig will be sent to all
51 processes excluding special processes whose real user ID is equal to
52 the effective user ID of the sender.
53 If pid is (pid_t)−1 and the {PRIV_PROC_OWNER} privilege is asserted in
56 the effective set of the sending process, sig will be sent to all pro‐
57 cesses excluding special processes.
58
60 Upon successful completion, 0 is returned. Otherwise, −1 is returned,
61 no signal is sent, and errno is set to indicate the error.
62
64 The kill() function will fail if:
65 EINVAL The sig argument is not a valid signal number.
67 EPERM The sig argument is SIGKILL and the pid argument is (pid_t)-1
70 (that is, the calling process does not have permission to
71 send the signal to any of the processes specified by pid).
72 The effective user of the calling process does not match the
74 real or saved user and the calling process does not have the
75 {PRIV_PROC_OWNER} privilege asserted in the effective set,
76 and the calling process either is not sending SIGCONT to a
77 process that shares the same session ID or does not have the
78 {PRIV_PROC_SESSION} privilege asserted and is trying to send
79 a signal to a process with a different session ID.
80 ESRCH No process or process group can be found corresponding to
83 that specified by pid.
84
87 The sigsend(2) function provides a more versatile way to send signals
88 to processes.
89
91 See attributes(5) for descriptions of the following attributes:
92 ┌─────────────────────────────┬─────────────────────────────┐
97 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
98 ├─────────────────────────────┼─────────────────────────────┤
99 │Interface Stability │Standard │
100 ├─────────────────────────────┼─────────────────────────────┤
101 │MT-Level │Async-Signal-Safe │
102 └─────────────────────────────┴─────────────────────────────┘
103
105 kill(1), Intro(2), exec(2), getpid(2), getsid(2), setpgrp(2), sigac‐
106 tion(2), sigsend(2), signal(3C), signal.h(3HEAD), attributes(5), privi‐
107 leges(5), standards(5)
108SunOS 5.11 22 Mar 2004 kill(2)