SpinLock.h

#ifdef __APPLE__
#include <errno.h>
#ifndef PTHREAD_SPIN_LOCK_SHIM
#define PTHREAD_SPIN_LOCK_SHIM

typedef int pthread_spinlock_t;

#ifndef PTHREAD_PROCESS_SHARED
# define PTHREAD_PROCESS_SHARED 1
#endif
#ifndef PTHREAD_PROCESS_PRIVATE
# define PTHREAD_PROCESS_PRIVATE 2
#endif

static inline int pthread_spin_init(pthread_spinlock_t *lock, int pshared) {
    __asm__ __volatile__ ("" ::: "memory");
    *lock = 0;
    return 0;
}

static inline int pthread_spin_destroy(pthread_spinlock_t *lock) {
    return 0;
}

static inline int pthread_spin_lock(pthread_spinlock_t *lock) {
    while (1) {
        int i;
        for (i=0; i < 10000; i++) {
            if (__sync_bool_compare_and_swap(lock, 0, 1)) {
                return 0;
            }
        }
        sched_yield();
    }
}

static inline int pthread_spin_trylock(pthread_spinlock_t *lock) {
    if (__sync_bool_compare_and_swap(lock, 0, 1)) {
        return 0;
    }
    return EBUSY;
}

static inline int pthread_spin_unlock(pthread_spinlock_t *lock) {
    __asm__ __volatile__ ("" ::: "memory");
    *lock = 0;
    return 0;
}

#endif

#endif