PTHREAD_SPIN_DESTROY(3P)                            POSIX Programmer's Manual                           PTHREAD_SPIN_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_spin_destroy, pthread_spin_init - destroy or initialize a spin lock object (ADVANCED REALTIME THREADS)

SYNOPSIS
       #include <pthread.h>

       int pthread_spin_destroy(pthread_spinlock_t *lock);
       int pthread_spin_init(pthread_spinlock_t *lock, int pshared);


DESCRIPTION
       The  pthread_spin_destroy() function shall destroy the spin lock referenced by lock and release any resources used by the
       lock. The effect of subsequent use of the lock  is  undefined  until  the  lock  is  reinitialized  by  another  call  to
       pthread_spin_init().  The  results  are undefined if pthread_spin_destroy() is called when a thread holds the lock, or if
       this function is called with an uninitialized thread spin lock.

       The pthread_spin_init() function shall allocate any resources required to use the spin lock referenced by lock  and  ini-
       tialize the lock to an unlocked state.

       If  the Thread Process-Shared Synchronization option is supported and the value of pshared is PTHREAD_PROCESS_SHARED, the
       implementation shall permit the spin lock to be operated upon by any thread that has access to the memory where the  spin
       lock is allocated, even if it is allocated in memory that is shared by multiple processes.

       If  the Thread Process-Shared Synchronization option is supported and the value of pshared is PTHREAD_PROCESS_PRIVATE, or
       if the option is not supported, the spin lock shall only be operated upon by threads created within the same  process  as
       the  thread that initialized the spin lock. If threads of differing processes attempt to operate on such a spin lock, the
       behavior is undefined.

       The results are undefined if pthread_spin_init() is called specifying an already initialized spin lock. The  results  are
       undefined if a spin lock is used without first being initialized.

       If the pthread_spin_init() function fails, the lock is not initialized and the contents of lock are undefined.

       Only the object referenced by lock may be used for performing synchronization.

       The   result   of   referring  to  copies  of  that  object  in  calls  to  pthread_spin_destroy(),  pthread_spin_lock(),
       pthread_spin_trylock(), or pthread_spin_unlock() is undefined.

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

ERRORS
       These functions may fail if:

       EBUSY  The  implementation  has detected an attempt to initialize or destroy a spin lock while it is in use (for example,
              while being used in a pthread_spin_lock() call) by another thread.

       EINVAL The value specified by lock is invalid.


       The pthread_spin_init() function shall fail if:

       EAGAIN The system lacks the necessary resources to initialize another spin lock.

       ENOMEM Insufficient memory exists to initialize the lock.


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

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       The pthread_spin_destroy() and pthread_spin_init() functions are part of the Spin Locks option and need not  be  provided
       on all implementations.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       pthread_spin_lock(), pthread_spin_unlock(), 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_SPIN_DESTROY(3P)