Name

tkill, tgkill — send a signal to a single process

Synopsis

int tkill( int   tid,
  int   sig);
int tgkill( int   tgid,
  int   tid,
  int   sig);

DESCRIPTION

The tkill() system call is analogous to kill(2), except when the specified process is part of a thread group (created by specifying the CLONE_THREAD flag in the call to clone(2)). Since all the processes in a thread group have the same PID, they cannot be individually signaled with kill(2). With tkill(), however, one can address each process by its unique TID.

The tgkill() call improves on tkill() by allowing the caller to specify the thread group ID of the thread to be signaled, protecting against TID reuse. If the tgid is specified as −1, tgkill() degenerates into tkill().

These are the raw system call interfaces, meant for internal thread library use.

RETURN VALUE

On success, zero is returned. On error, −1 is returned, and errno is set appropriately.

ERRORS

EINVAL

An invalid TID or signal was specified.

EPERM

Permission denied. For the required permissions, see kill(2).

ESRCH

No process with the specified thread ID (and thread group ID) exists.

VERSIONS

tkill() is supported since Linux 2.4.19 / 2.5.4. tgkill() was added in Linux 2.5.75.

CONFORMING TO

tkill() and tgkill() are Linux specific and should not be used in programs that are intended to be portable.

NOTES

Glibc does not provide wrapper for these system calls; call them using syscall(2).

SEE ALSO

gettid(2), kill(2)

COLOPHON

This page is part of release 2.70 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/.


Copyright 2003 Abhijit Menon-Sen <amswiw.org>
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided that the
entire resulting derived work is distributed under the terms of a
permission notice identical to this one.

Since the Linux kernel and libraries are constantly changing, this
manual page may be incorrect or out-of-date.  The author(s) assume no
responsibility for errors or omissions, or for damages resulting from
the use of the information contained herein.  The author(s) may not
have taken the same level of care in the production of this manual,
which is licensed free of charge, as they might when working
professionally.

Formatted or processed versions of this manual, if unaccompanied by
the source, must acknowledge the copyright and authors of this work.

2004-05-31, added tgkill, ahu, aeb