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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 (consult 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 terminat-
       ing 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 lim-
       ited to, calling 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 cancella-
       tion 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, references to  local  vari-
       ables  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_create() call that started
       it. The pthread_exit() function provides the capability for a thread to
       terminate  without  requiring  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 cancella-
       tion 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_CAN-
       CELED), 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,  Copyright  (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.opengroup.org/unix/online.html .

IEEE/The Open Group                  2003                     PTHREAD_EXIT(3P)