NAME

       pthread_spin_lock, pthread_spin_trylock, pthread_spin_unlock - lock and unlock a spin lock

LIBRARY

       POSIX threads library (libpthread, -lpthread)

SYNOPSIS

       #include <pthread.h>

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

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       pthread_spin_lock(), pthread_spin_trylock():
           _POSIX_C_SOURCE >= 200112L

DESCRIPTION

       The  pthread_spin_lock()  function  locks  the spin lock referred to by lock.  If the spin
       lock is currently unlocked, the calling thread acquires the lock immediately.  If the spin
       lock  is  currently  locked  by another thread, the calling thread spins, testing the lock
       until it becomes available, at which point the calling thread acquires the lock.

       Calling pthread_spin_lock() on a lock that is already held by the caller or  a  lock  that
       has not been initialized with pthread_spin_init(3) results in undefined behavior.

       The  pthread_spin_trylock()  function is like pthread_spin_lock(), except that if the spin
       lock referred to by lock is currently locked, then, instead of spinning, the call  returns
       immediately with the error EBUSY.

       The pthread_spin_unlock() function unlocks the spin lock referred to lock.  If any threads
       are spinning on the lock, one of those threads will then acquire the lock.

       Calling pthread_spin_unlock() on a lock  that  is  not  held  by  the  caller  results  in
       undefined behavior.

RETURN VALUE

       On success, these functions return zero.  On failure, they return an error number.

ERRORS

       pthread_spin_lock() may fail with the following errors:

       EDEADLOCK
              The system detected a deadlock condition.

       pthread_spin_trylock() fails with the following errors:

       EBUSY  The spin lock is currently locked by another thread.

STANDARDS

       POSIX.1-2008.

HISTORY

       glibc 2.2.  POSIX.1-2001.

CAVEATS

       Applying any of the functions described on this page to an uninitialized spin lock results
       in undefined behavior.

       Carefully read NOTES in pthread_spin_init(3).

SEE ALSO

       pthread_spin_destroy(3), pthread_spin_init(3), pthreads(7)