tkill
Section: System Calls (2)
Updated: 2022-12-04
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NAME
tkill, tgkill - send a signal to a thread
LIBRARY
Standard C library
(libc, -lc)
SYNOPSIS
#include <signal.h> /* Definition of SIG* constants */
#include <sys/syscall.h> /* Definition of SYS_* constants */
#include <unistd.h>
[[deprecated]] int syscall(SYS_tkill, pid_t tid, int sig);
#include <signal.h>
int tgkill(pid_t tgid, pid_t tid, int sig);
Note:
glibc provides no wrapper for
tkill(),
necessitating the use of
syscall(2).
DESCRIPTION
tgkill()
sends the signal
sig
to the thread with the thread ID
tid
in the thread group
tgid.
(By contrast,
kill(2)
can 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.)
tkill()
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.
RETURN VALUE
On success, zero is returned.
On error, -1 is returned, and errno
is set to indicate the error.
ERRORS
- EAGAIN
-
The
RLIMIT_SIGPENDING
resource limit was reached and
sig
is a real-time signal.
- EAGAIN
-
Insufficient kernel memory was available and
sig
is a real-time signal.
- EINVAL
-
An invalid thread ID, thread group ID, 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.
Library support for
tgkill()
was added in glibc 2.30.
STANDARDS
tkill()
and
tgkill()
are Linux-specific and should not be used
in programs that are intended to be portable.
NOTES
See the description of
CLONE_THREAD
in
clone(2)
for an explanation of thread groups.
Before glibc 2.30, there was also no wrapper function for
tgkill().
SEE ALSO
clone(2),
gettid(2),
kill(2),
rt_sigqueueinfo(2)
Index
- NAME
-
- LIBRARY
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- VERSIONS
-
- STANDARDS
-
- NOTES
-
- SEE ALSO
-
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Time: 12:04:58 GMT, April 25, 2024