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



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

NAME
       pthread_kill -- send a signal to a thread

SYNOPSIS
       #include <signal.h>

       int pthread_kill(pthread_t thread, int sig);

DESCRIPTION
       The pthread__kill() function shall request that a signal be delivered to
       the specified thread.

       As in kill(), if sig is zero, error checking shall be performed but no
       signal shall actually be sent.

RETURN VALUE
       Upon successful completion, the function shall return a value of zero.
       Otherwise, the function shall return an error number. If the
       pthread__kill() function fails, no signal shall be sent.

ERRORS
       The pthread__kill() function shall fail if:

       EINVAL The value of the sig argument is an invalid or unsupported
              signal number.

       The pthread__kill() function shall not return an error code of [EINTR].

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       The pthread__kill() function provides a mechanism for asynchronously
       directing a signal at a thread in the calling process. This could be
       used, for example, by one thread to affect broadcast delivery of a
       signal to a set of threads.

       Note that pthread__kill() only causes the signal to be handled in the
       context of the given thread; the signal action (termination or
       stopping) affects the process as a whole.

RATIONALE
       If an implementation detects use of a thread ID after the end of its
       lifetime, it is recommended that the function should fail and report an
       [ESRCH] error.

       Existing implementations vary on the result of a pthread__kill() with a
       thread ID indicating an inactive thread (a terminated thread that has
       not been detached or joined). Some indicate success on such a call,
       while others give an error of [ESRCH].  Since the definition of thread
       lifetime in this volume of POSIX.1-2017 covers inactive threads, the
       [ESRCH] error as described is inappropriate in this case. In
       particular, this means that an application cannot have one thread check
       for termination of another with pthread__kill().

FUTURE DIRECTIONS
       A future version of this standard may require that pthread__kill() not
       fail with [ESRCH] in the case of sending signals to an inactive thread
       (a terminated thread not yet detached or joined), even though no signal
       will be delivered because the thread is no longer running.

SEE ALSO
       kill(), pthread__self(), raise()

       The Base Definitions volume of POSIX.1-2017, <signal.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  In the event of any discrepancy between this version and the
       original IEEE and The Open Group Standard, the original IEEE and The
       Open Group Standard is the referee document. The original Standard can
       be obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2017                      PTHREAD_KILL(3)
