1RT_SIGQUEUEINFO(2) Linux Programmer's Manual RT_SIGQUEUEINFO(2)
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6 rt_sigqueueinfo, rt_tgsigqueueinfo - queue a signal and data
7
9 int rt_sigqueueinfo(pid_t tgid, int sig, siginfo_t *uinfo);
10 int rt_tgsigqueueinfo(pid_t tgid, pid_t tid, int sig,
12 siginfo_t *uinfo);
13 Note: There are no glibc wrappers for these system calls; see NOTES.
15
17 The rt_sigqueueinfo() and rt_tgsigqueueinfo() system calls are the low-
18 level interfaces used to send a signal plus data to a process or
19 thread. The receiver of the signal can obtain the accompanying data by
20 establishing a signal handler with the sigaction(2) SA_SIGINFO flag.
21 These system calls are not intended for direct application use; they
23 are provided to allow the implementation of sigqueue(3) and
24 pthread_sigqueue(3).
25 The rt_sigqueueinfo() system call sends the signal sig to the thread
27 group with the ID tgid. (The term "thread group" is synonymous with
28 "process", and tid corresponds to the traditional UNIX process ID.)
29 The signal will be delivered to an arbitrary member of the thread group
30 (i.e., one of the threads that is not currently blocking the signal).
31 The uinfo argument specifies the data to accompany the signal. This
33 argument is a pointer to a structure of type siginfo_t, described in
34 sigaction(2) (and defined by including <sigaction.h>). The caller
35 should set the following fields in this structure:
36 si_code
38 This must be one of the SI_* codes in the Linux kernel source
39 file include/asm-generic/siginfo.h, with the restriction that
40 the code must be negative (i.e., cannot be SI_USER, which is
41 used by the kernel to indicate a signal sent by kill(2)) and
42 cannot (since Linux 2.6.39) be SI_TKILL (which is used by the
43 kernel to indicate a signal sent using tgkill(2)).
44 si_pid This should be set to a process ID, typically the process ID of
46 the sender.
47 si_uid This should be set to a user ID, typically the real user ID of
49 the sender.
50 si_value
52 This field contains the user data to accompany the signal. For
53 more information, see the description of the last (union sigval)
54 argument of sigqueue(3).
55 Internally, the kernel sets the si_signo field to the value specified
57 in sig, so that the receiver of the signal can also obtain the signal
58 number via that field.
59 The rt_tgsigqueueinfo() system call is like rt_sigqueueinfo(), but
61 sends the signal and data to the single thread specified by the combi‐
62 nation of tgid, a thread group ID, and tid, a thread in that thread
63 group.
64
66 On success, these system calls return 0. On error, they return -1 and
67 errno is set to indicate the error.
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70 EAGAIN The limit of signals which may be queued has been reached. (See
71 signal(7) for further information.)
72 EINVAL sig, tgid, or tid was invalid.
74 EPERM The caller does not have permission to send the signal to the
76 target. For the required permissions, see kill(2). Or:
77 uinfo->si_code is invalid.
78 ESRCH rt_sigqueueinfo(): No thread group matching tgid was found.
80 rt_tgsigqueinfo(): No thread matching tgid and tid was found.
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84 The rt_sigqueueinfo() system call was added to Linux in version 2.2.
85 The rt_tgsigqueueinfo() system call was added to Linux in version
86 2.6.31.
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89 These system calls are Linux-specific.
90
92 Since these system calls are not intended for application use, there
93 are no glibc wrapper functions; use syscall(2) in the unlikely case
94 that you want to call them directly.
95 As with kill(2), the null signal (0) can be used to check if the speci‐
97 fied process or thread exists.
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100 kill(2), sigaction(2), sigprocmask(2), tgkill(2), pthread_sigqueue(3),
101 sigqueue(3), signal(7)
102
104 This page is part of release 4.15 of the Linux man-pages project. A
105 description of the project, information about reporting bugs, and the
106 latest version of this page, can be found at
107 https://www.kernel.org/doc/man-pages/.
108Linux 2017-09-15 RT_SIGQUEUEINFO(2)