NAME¶

SYNOPSIS¶

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);

Note: There are no glibc wrappers for these system calls; see NOTES.

DESCRIPTION¶

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 Linux 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.

RETURN VALUE¶

ERRORS¶

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.

VERSIONS¶

CONFORMING TO¶

NOTES¶

As with kill(2), the null signal (0) can be used to check if the specified process or thread exists.

SEE ALSO¶

COLOPHON¶