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 .