tkill, tgkill - send a signal to a thread
int tkill(int tid, int sig);
int tgkill(int tgid, int tid, int sig);
: There are no glibc wrappers for these system calls; see NOTES.
() sends the signal sig
to the thread with the thread ID
in the thread group tgid
. (By contrast, kill(2)
be used to send a signal only to a process (i.e., thread group) as a whole,
and the signal will be delivered to an arbitrary thread within that process.)
() is an obsolete predecessor to tgkill
(). It allows only the
target thread ID to be specified, which may result in the wrong thread being
signaled if a thread terminates and its thread ID is recycled. Avoid using
this system call.
These are the raw system call interfaces, meant for internal thread library use.
On success, zero is returned. On error, -1 is returned, and errno
- An invalid thread ID, thread group ID, or signal was specified.
- Permission denied. For the required permissions, see kill(2).
- No process with the specified thread ID (and thread group ID) exists.
- The RLIMIT_SIGPENDING resource limit was reached and sig is
a real-time signal.
- Insufficient kernel memory was available and sig is a real-time
() is supported since Linux 2.4.19 / 2.5.4. tgkill
added in Linux 2.5.75.
() and tgkill
() are Linux-specific and should not be used in
programs that are intended to be portable.
See the description of CLONE_THREAD
for an explanation
of thread groups.
Glibc does not provide wrappers for these system calls; call them using
This page is part of release 4.10 of the Linux man-pages
description of the project, information about reporting bugs, and the latest
version of this page, can be found at