noble (3) pthread_spin_destroy.3posix.gz

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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_spin_destroy, pthread_spin_init — destroy or initialize a spin lock object


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 initialize 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.

       See Section 2.9.9, Synchronization Object Copies and Alternative Mappings for further requirements.

       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
       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
       None.


RATIONALE
       If an implementation detects that the value specified by the lock argument to pthread_spin_destroy() does
       not refer to an initialized spin lock object, it is recommended that the function should fail and  report
       an [EINVAL] error.

       If  an  implementation detects that the value specified by the lock argument to pthread_spin_destroy() or
       pthread_spin_init() refers to a locked spin lock object, or detects that the value specified by the  lock
       argument to pthread_spin_init() refers to an already initialized spin lock object, it is recommended that
       the function should fail and report an [EBUSY] error.


FUTURE DIRECTIONS
       None.


SEE ALSO
       pthread_spin_lock(), pthread_spin_unlock()

       The Base Definitions volume of POSIX.1‐2017, <pthread.h>


       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 .