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 .