Section: Linux Programmer's Manual (2)
rt_sigqueueinfo, rt_tgsigqueueinfo - queue a signal and data
int rt_sigqueueinfo(pid_t tgid, int sig, siginfo_t *info);
int rt_tgsigqueueinfo(pid_t tgid, pid_t tid, int sig,
There are no glibc wrappers for these system calls; see NOTES.
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
These system calls are not intended for direct application use;
they are provided to allow the implementation of
system call sends the signal
to the thread group with the ID
(The term "thread group" is synonymous with "process", and
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).
argument specifies the data to accompany the signal.
This argument is a pointer to a structure of type
(and defined by including
The caller should set the following fields in this structure:
This should be one of the
codes in the Linux kernel source file
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
which is used by the kernel to indicate a signal sent by
and nor can it be
which is used to indicate a signal generated by the kernel.
The code can't (since Linux 2.6.39) be
which is used by the kernel to indicate a signal sent using
This should be set to a process ID,
typically the process ID of the sender.
This should be set to a user ID,
typically the real user ID of the sender.
This field contains the user data to accompany the signal.
For more information, see the description of the last
Internally, the kernel sets the
field to the value specified in
so that the receiver of the signal can also obtain
the signal number via that field.
system call is like
but sends the signal and data to the single thread
specified by the combination of
a thread group ID,
a thread in that thread group.
On success, these system calls return 0.
On error, they return -1 and
is set to indicate the error.
The limit of signals which may be queued has been reached.
for further information.)
The caller does not have permission to send the signal to the target.
For the required permissions, see
specifies a process other than the caller and
No thread group matching
No thread matching
system call was added to Linux in version 2.2.
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
in the unlikely case that you want to call them directly.
the null signal (0) can be used to check if the specified process
or thread exists.
This page is part of release 5.10 of the Linux
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at