The pthread_spin_lock function will acquire lock if it is not currently owned by another thread. If the lock cannot be acquired immediately, it will spin attempting to acquire the lock (it will not sleep) until it becomes available.
The pthread_spin_trylock function is the same as pthread_spin_lock except that if it cannot acquire lock immediately it will return with an error.
The pthread_spin_unlock function will release lock, which must have been previously locked by a call to pthread_spin_lock or pthread_spin_trylock.
If successful, all these functions will return zero. Otherwise, an error number will be returned to indicate the error.
None of these functions will return EINTR.
The pthread_spin_lock, pthread_spin_trylock and pthread_spin_unlock functions will fail if: