rt_sigqueueinfo(2) - Linux manual page (original) (raw)
rtsigqueueinfo(2) System Calls Manual rtsigqueueinfo(2)
NAME top
rt_sigqueueinfo, rt_tgsigqueueinfo - queue a signal and dataLIBRARY top
Standard C library (_libc_, _-lc_)SYNOPSIS top
**#include <linux/signal.h>** /* Definition of **SI_*** constants */
**#include <sys/syscall.h>** /* Definition of **SYS_*** constants */
**#include <unistd.h>**
**int syscall(SYS_rt_sigqueueinfo, pid_t** _tgid_**,**
**int** _sig_**, siginfo_t ***_info_**);**
**int syscall(SYS_rt_tgsigqueueinfo, pid_t** _tgid_**, pid_t** _tid_**,**
**int** _sig_**, siginfo_t ***_info_**);**
_Note_: There are no glibc wrappers for these system calls; see
NOTES.DESCRIPTION top
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)](../man2/sigaction.2.html)
**SA_SIGINFO** flag.
These system calls are not intended for direct application use;
they are provided to allow the implementation of [sigqueue(3)](../man3/sigqueue.3.html) and
[pthread_sigqueue(3)](../man3/pthread%5Fsigqueue.3.html).
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 _info_ argument specifies the data to accompany the signal.
This argument is a pointer to a structure of type _siginfot_,
described in [sigaction(2)](../man2/sigaction.2.html) (and defined by including
_<sigaction.h>_). The caller should set the following fields in
this structure:
_sicode_
This should be one of the **SI_*** codes in the Linux kernel
source file _include/asm-generic/siginfo.h_. If the signal
is being sent to any process other than the caller itself,
the following restrictions apply:
• The code can't be a value greater than or equal to zero.
In particular, it can't be **SI_USER**, which is used by the
kernel to indicate a signal sent by [kill(2)](../man2/kill.2.html), and nor can
it be **SI_KERNEL**, which is used to indicate a signal
generated by the kernel.
• The code can't (since Linux 2.6.39) be **SI_TKILL**, which
is used by the kernel to indicate a signal sent using
[tgkill(2)](../man2/tgkill.2.html).
_sipid_ This should be set to a process ID, typically the process
ID of the sender.
_siuid_ This should be set to a user ID, typically the real user ID
of the sender.
_sivalue_
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)](../man3/sigqueue.3.html).
Internally, the kernel sets the _sisigno_ 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.RETURN VALUE top
On success, these system calls return 0. On error, they return -1
and _[errno](../man3/errno.3.html)_ is set to indicate the error.ERRORS top
**EAGAIN** The limit of signals which may be queued has been reached.
(See [signal(7)](../man7/signal.7.html) 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)](../man2/kill.2.html).
**EPERM** _tgid_ specifies a process other than the caller and
_info->sicode_ is invalid.
**ESRCH rt_sigqueueinfo**(): No thread group matching _tgid_ was found.
**rt_tgsigqueinfo**(): No thread matching _tgid_ and _tid_ was found.STANDARDS top
Linux.HISTORY top
**rt_sigqueueinfo**()
Linux 2.2.
**rt_tgsigqueueinfo**()
Linux 2.6.31.NOTES top
Since these system calls are not intended for application use,
there are no glibc wrapper functions; use [syscall(2)](../man2/syscall.2.html) in the
unlikely case that you want to call them directly.
As with [kill(2)](../man2/kill.2.html), the null signal (0) can be used to check if the
specified process or thread exists.SEE ALSO top
[kill(2)](../man2/kill.2.html), [pidfd_send_signal(2)](../man2/pidfd%5Fsend%5Fsignal.2.html), [sigaction(2)](../man2/sigaction.2.html), [sigprocmask(2)](../man2/sigprocmask.2.html),
[tgkill(2)](../man2/tgkill.2.html), [pthread_sigqueue(3)](../man3/pthread%5Fsigqueue.3.html), [sigqueue(3)](../man3/sigqueue.3.html), [signal(7)](../man7/signal.7.html)COLOPHON top
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man-pages@man7.orgLinux man-pages 6.10 2024-07-23 rtsigqueueinfo(2)
Pages that refer to this page:pidfd_send_signal(2), syscalls(2), tkill(2), pthread_sigqueue(3), sd_event_add_child(3), sigqueue(3), signal(7), system_data_types(7)