Open Source Software

tgkill(2)



NAME

   tkill, tgkill - send a signal to a thread

SYNOPSIS

   int tkill(int tid, int sig);

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

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

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 appropriately.

ERRORS

   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.

CONFORMING TO

   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.

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

SEE ALSO

   clone(2), gettid(2), kill(2), rt_sigqueueinfo(2)

COLOPHON

   This page is part of release 4.09 of the Linux  man-pages  project.   A
   description  of  the project, information about reporting bugs, and the
   latest    version    of    this    page,    can     be     found     at
   https://www.kernel.org/doc/man-pages/.



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