PTHREAD_KILL(3)                                                         Linux Programmer's Manual                                                        PTHREAD_KILL(3)

NAME
       pthread_kill - send a signal to a thread

SYNOPSIS
       #include <signal.h>

       int pthread_kill(pthread_t thread, int sig);

       Compile and link with -pthread.

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       pthread_kill():
           _POSIX_C_SOURCE >= 199506L || _XOPEN_SOURCE >= 500

DESCRIPTION
       The pthread_kill() function sends the signal sig to thread, a thread in the same process as the caller.  The signal is asynchronously directed to thread.

       If sig is 0, then no signal is sent, but error checking is still performed.

RETURN VALUE
       On success, pthread_kill() returns 0; on error, it returns an error number, and no signal is sent.

ERRORS
       EINVAL An invalid signal was specified.

ATTRIBUTES
       For an explanation of the terms used in this section, see attributes(7).

       ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┬───────────────┬─────────┐
       │Interface                                                                                                                             │ Attribute     │ Value   │
       ├──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┼───────────────┼─────────┤
       │pthread_kill()                                                                                                                        │ Thread safety │ MT-Safe │
       └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘

CONFORMING TO
       POSIX.1-2001, POSIX.1-2008.

NOTES
       Signal dispositions are process-wide: if a signal handler is installed, the handler will be invoked in the thread thread, but if the disposition of the signal is
       "stop", "continue", or "terminate", this action will affect the whole process.

       The glibc implementation of pthread_kill() gives an error (EINVAL) on attempts to send either of the real-time signals used internally by the NPTL threading  im‐
       plementation.  See nptl(7) for details.

       POSIX.1-2008  recommends  that  if  an implementation detects the use of a thread ID after the end of its lifetime, pthread_kill() should return the error ESRCH.
       The glibc implementation returns this error in the cases where an invalid thread ID can be detected.  But note also that POSIX says that  an  attempt  to  use  a
       thread  ID whose lifetime has ended produces undefined behavior, and an attempt to use an invalid thread ID in a call to pthread_kill() can, for example, cause a
       segmentation fault.

SEE ALSO
       kill(2), sigaction(2), sigpending(2), pthread_self(3), pthread_sigmask(3), raise(3), pthreads(7), signal(7)

Linux                                                                          2021-03-22                                                                PTHREAD_KILL(3)