| NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | VERSIONS | CONFORMING TO | NOTES | SEE ALSO | COLOPHON | The Linux Programming Interface |
RT_SIGQUEUEINFO(2) Linux Programmer's Manual RT_SIGQUEUEINFO(2)
rt_sigqueueinfo, rt_tgsigqueueinfo - queue a signal and data
int rt_sigqueueinfo(pid_t tgid, int sig, siginfo_t *uinfo);
int rt_tgsigqueueinfo(pid_t tgid, pid_t tid, int sig,
siginfo_t *uinfo);
The rt_sigqueueinfo() and rt_tgsigqueueinfo() system calls are the low-
level interfaces used to send a signal plus data to a process or thread.
The receiver of the signal can obtain the accompanying data by establishing
a signal handler with the sigaction(2) SA_SIGINFO flag.
These system calls are not intended for direct application use; they are
provided to allow the implementation of sigqueue(3) and
pthread_sigqueue(3).
The rt_sigqueueinfo() system call sends the signal sig to the thread group
with the ID tgid. (The term "thread group" is synonymous with "process",
and tid corresponds to the traditional UNIX process ID.) The signal will
be delivered to an arbitrary member of the thread group (i.e., one of the
threads that is not currently blocking the signal).
The uinfo argument specifies the data to accompany the signal. This
argument is a pointer to a structure of type siginfo_t, described in
sigaction(2) (and defined by including <sigaction.h>). The caller should
set the following fields in this structure:
si_code
This must be one of the SI_* codes in the kernel source file
include/asm-generic/siginfo.h, with the restriction that the code
must be negative (i.e., cannot be SI_USER, which is used by the
kernel to indicate a signal sent by kill(2)) and cannot (since Linux
2.6.39) be SI_TKILL (which is used by the kernel to indicate a
signal sent using tgkill(2)).
si_pid This should be set to a process ID, typically the process ID of the
sender.
si_uid This should be set to a user ID, typically the real user ID of the
sender.
si_value
This field contains the user data to accompany the signal. For more
information, see the description of the last (union sigval) argument
of sigqueue(3).
Internally, the kernel sets the si_signo field to the value specified in
sig, so that the receiver of the signal can also obtain the signal number
via that field.
The rt_tgsigqueueinfo() system call is like rt_sigqueueinfo(), but sends
the signal and data to the single thread specified by the combination of
tgid, a thread group ID, and tid, a thread in that thread group.
On success, these system calls return 0. On error, they return -1 and
errno is set to indicate the error.
EAGAIN The limit of signals which may be queued has been reached. (See
signal(7) for further information.)
EINVAL sig, tgid, or tid was invalid.
EPERM The caller does not have permission to send the signal to the
target. For the required permissions, see kill(2). Or:
uinfo->si_code is invalid.
ESRCH rt_sigqueueinfo(): No thread group matching tgid was found.
rt_tgsigqueinfo(): No thread matching tgid and tid was found.
The rt_sigqueueinfo() system call was added to Linux in version 2.2. The
rt_tgsigqueueinfo() system call was added to Linux in version 2.6.31.
These system calls are Linux-specific.
Since these system calls are not intended for application use, there are no
glibc wrapper functions; use syscall(2) in the unlikely case that you want
to call them directly.
As with kill(2), the null signal (0) can be used to check if the specified
process or thread exists.
kill(2), sigaction(2), sigprocmask(2), tgkill(2), pthread_sigqueue(3),
sigqueue(3), signal(7)
This page is part of release 3.41 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can be
found at http://www.kernel.org/doc/man-pages/.
Linux 2011-09-18 RT_SIGQUEUEINFO(2)
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