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_lock, pthread_spin_trylock — lock a spin lock object

SYNOPSIS

       #include <pthread.h>

       int pthread_spin_lock(pthread_spinlock_t *lock);
       int pthread_spin_trylock(pthread_spinlock_t *lock);

DESCRIPTION

       The  pthread_spin_lock()  function shall lock the spin lock referenced by lock.  The calling thread shall
       acquire the lock if it is not held by another thread. Otherwise, the thread shall spin  (that  is,  shall
       not return from the pthread_spin_lock() call) until the lock becomes available. The results are undefined
       if  the  calling  thread holds the lock at the time the call is made. The pthread_spin_trylock() function
       shall lock the spin lock referenced by lock if it is not held by  any  thread.  Otherwise,  the  function
       shall fail.

       The results are undefined if any of these functions is called with an uninitialized spin lock.

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_lock() function may fail if:

       EDEADLK
              A deadlock condition was detected.

       The pthread_spin_trylock() function shall fail if:

       EBUSY  A thread currently holds the lock.

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

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       Applications using this function may  be  subject  to  priority  inversion,  as  discussed  in  the  Base
       Definitions volume of POSIX.1‐2017, Section 3.291, Priority Inversion.

RATIONALE

       If  an  implementation  detects  that  the value specified by the lock argument to pthread_spin_lock() or
       pthread_spin_trylock() 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_lock() refers
       to a spin lock object for which the calling thread already holds the lock, it  is  recommended  that  the
       function should fail and report an [EDEADLK] error.

FUTURE DIRECTIONS

       None.

SEE ALSO

       pthread_spin_destroy(), pthread_spin_unlock()

       The  Base  Definitions  volume  of  POSIX.1‐2017, Section 3.291, Priority Inversion, Section 4.12, Memory
       Synchronization, <pthread.h>

COPYRIGHT

       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 .

IEEE/The Open Group                                   2017                             PTHREAD_SPIN_LOCK(3POSIX)