tkill, tgkill - send a signal to a thread


   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.


   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.


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


   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)


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


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


   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


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


   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


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