PTHREAD_BARRIER_DESTROY(3P)                         POSIX Programmer's Manual                        PTHREAD_BARRIER_DESTROY(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_barrier_destroy, pthread_barrier_init - destroy and initialize a barrier object (ADVANCED REALTIME THREADS)

SYNOPSIS
       #include <pthread.h>

       int pthread_barrier_destroy(pthread_barrier_t *barrier);
       int pthread_barrier_init(pthread_barrier_t *restrict barrier,
              const pthread_barrierattr_t *restrict attr, unsigned count);


DESCRIPTION
       The  pthread_barrier_destroy() function shall destroy the barrier referenced by barrier and release any resources used by
       the barrier. The effect of subsequent use of the barrier is undefined until the barrier is reinitialized by another  call
       to  pthread_barrier_init().  An  implementation may use this function to set barrier to an invalid value. The results are
       undefined if pthread_barrier_destroy() is called when any thread is blocked on the barrier, or if this function is called
       with an uninitialized barrier.

       The  pthread_barrier_init()  function  shall allocate any resources required to use the barrier referenced by barrier and
       shall initialize the barrier with attributes referenced by attr.  If attr is NULL, the default barrier  attributes  shall
       be  used; the effect is the same as passing the address of a default barrier attributes object. The results are undefined
       if pthread_barrier_init() is called when any thread is blocked on the  barrier  (that  is,  has  not  returned  from  the
       pthread_barrier_wait() call). The results are undefined if a barrier is used without first being initialized. The results
       are undefined if pthread_barrier_init() is called specifying an already initialized barrier.

       The count argument specifies the number of threads that must call pthread_barrier_wait() before any of them  successfully
       return from the call.  The value specified by count must be greater than zero.

       If  the pthread_barrier_init() function fails, the barrier shall not be initialized and the contents of barrier are unde-
       fined.

       Only the object referenced by barrier may be used for performing synchronization. The result of referring  to  copies  of
       that object in calls to pthread_barrier_destroy() or pthread_barrier_wait() is undefined.

RETURN VALUE
       Upon  successful  completion, these functions shall return zero; otherwise, an error number shall be returned to indicate
       the error.

ERRORS
       The pthread_barrier_destroy() function may fail if:

       EBUSY  The implementation has detected an attempt to destroy a barrier while it is in use (for example, while being  used
              in a pthread_barrier_wait() call) by another thread.

       EINVAL The value specified by barrier is invalid.


       The pthread_barrier_init() function shall fail if:

       EAGAIN The system lacks the necessary resources to initialize another barrier.

       EINVAL The value specified by count is equal to zero.

       ENOMEM Insufficient memory exists to initialize the barrier.


       The pthread_barrier_init() function may fail if:

       EBUSY  The  implementation has detected an attempt to reinitialize a barrier while it is in use (for example, while being
              used in a pthread_barrier_wait() call) by another thread.

       EINVAL The value specified by attr is invalid.


       These functions shall not return an error code of [EINTR].

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       The pthread_barrier_destroy() and pthread_barrier_init() functions are part of the Barriers option and need not  be  pro-
       vided on all implementations.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       pthread_barrier_wait(), 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_BARRIER_DESTROY(3P)