PTHREAD_EXIT(3P)                                    POSIX Programmer's Manual                                   PTHREAD_EXIT(3P)



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

NAME
       pthread_exit - thread termination

SYNOPSIS
       #include <pthread.h>

       void pthread_exit(void *value_ptr);


DESCRIPTION
       The  pthread_exit()  function shall terminate the calling thread and make the value value_ptr available to any successful
       join with the terminating thread. Any cancellation cleanup handlers that have been pushed and not  yet  popped  shall  be
       popped  in  the reverse order that they were pushed and then executed.  After all cancellation cleanup handlers have been
       executed, if the thread has any thread-specific data, appropriate destructor functions shall be called in an  unspecified
       order.  Thread  termination  does  not  release any application visible process resources, including, but not limited to,
       mutexes and file descriptors, nor does it perform any process-level cleanup actions, including, but not limited to, call-
       ing any atexit() routines that may exist.

       An  implicit call to pthread_exit() is made when a thread other than the thread in which main() was first invoked returns
       from the start routine that was used to create it. The function's return value shall serve as the thread's exit status.

       The behavior of pthread_exit() is undefined if called from a cancellation cleanup handler or destructor function that was
       invoked as a result of either an implicit or explicit call to pthread_exit().

       After  a  thread  has terminated, the result of access to local (auto) variables of the thread is undefined. Thus, refer-
       ences to local variables of the exiting thread should not be used for the pthread_exit() value_ptr parameter value.

       The process shall exit with an exit status of 0 after the last thread has been terminated. The behavior shall  be  as  if
       the implementation called exit() with a zero argument at thread termination time.

RETURN VALUE
       The pthread_exit() function cannot return to its caller.

ERRORS
       No errors are defined.

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       None.

RATIONALE
       The  normal  mechanism  by which a thread terminates is to return from the routine that was specified in the pthread_cre-
       ate() call that started it. The pthread_exit() function provides the capability for a thread to terminate without requir-
       ing a return from the start routine of that thread, thereby providing a function analogous to exit().

       Regardless  of  the  method  of  thread  termination, any cancellation cleanup handlers that have been pushed and not yet
       popped are  executed,  and  the  destructors  for  any  existing  thread-specific  data  are  executed.  This  volume  of
       IEEE Std 1003.1-2001  requires  that  cancellation cleanup handlers be popped and called in order. After all cancellation
       cleanup handlers have been executed, thread-specific data destructors are called, in an unspecified order, for each  item
       of  thread-specific  data that exists in the thread. This ordering is necessary because cancellation cleanup handlers may
       rely on thread-specific data.

       As the meaning of the status is determined by the application (except when the thread has been canceled, in which case it
       is  PTHREAD_CANCELED),  the  implementation  has  no  idea what an illegal status value is, which is why no address error
       checking is done.

FUTURE DIRECTIONS
       None.

SEE ALSO
       exit(), pthread_create(), pthread_join(), the Base Definitions volume of IEEE Std 1003.1-2001, <pthread.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003  Edition,  Standard  for
       Information  Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copy-
       right (C) 2001-2003 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.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                              PTHREAD_EXIT(3P)