diff --git a/ao-play-async/ao_playasync.c b/ao-play-async/ao_playasync.c
index dff68b5..93b0a45 100644
--- a/ao-play-async/ao_playasync.c
+++ b/ao-play-async/ao_playasync.c
@@ -56,7 +56,6 @@ typedef int(*ao_play_func_t)(void *, char *, uint32_t);
 typedef struct {
     Queue_t        *play_queue;
     Queue_t        *last_frame;
-    sem_t           queue_sem;
 
     int             paused;
 
@@ -71,6 +70,7 @@ typedef struct {
     pthread_mutex_t mutex;
     pthread_mutex_t pause_mutex;
     pthread_t       thread;
+    sem_t          *queue_sem;
 #endif
     double          at_second;
     double          music_duration;
@@ -89,7 +89,11 @@ static Queue_t *front(AO_Handle *h)
 
 static Queue_t *get(AO_Handle *h)
 {
-    sem_wait(&h->queue_sem);
+#ifdef USE_PTHREADS
+    sem_wait(h->queue_sem);
+#endif
+#ifdef USE_WINDOWS_THREADS
+#endif
     MUTEX_LOCK(h->mutex);
     assert(h->play_queue != NULL);
     Queue_t *q = h->play_queue;
@@ -119,8 +123,12 @@ static void add(AO_Handle *h, Queue_t *elem)
         h->last_frame = elem;
     }
     h->buf_size += elem->buflen;
+#ifdef USE_PTHREADS
+    sem_post(h->queue_sem);
+#endif
+#ifdef USE_WINDOWS_THREADS
+#endif
     MUTEX_UNLOCK(h->mutex);
-    sem_post(&h->queue_sem);
 }
 
 static Queue_t *new_elem(int command, double at_second, double music_duration, int buf_len, void *buf)
@@ -154,9 +162,30 @@ static void del_elem(Queue_t *q)
 
 static void clear(AO_Handle *h)
 {
+/*
+    MUTEX_LOCK(h->mutex);
     while (h->play_queue != NULL) {
-        Queue_t *q = get(h);
-        del_elem(q);
+      Queue_t *q = h->play_queue;
+      h->play_queue = h->play_queue->next;
+      del_elem(q);
+      if (h->play_queue == NULL) {
+          h->last_frame = NULL;
+      } else {
+          h->play_queue->prev = NULL;
+      }
+    }
+#ifdef USE_PTHREADS
+    sem_destroy(h->queue_sem);
+    sem_init(h->queue_sem, 0, 0);
+#endif
+
+#ifdef USE_WINDOWS_THREADS
+#endif
+    MUTEX_UNLOCK(h->mutex);
+*/
+    while (h->play_queue != NULL) {
+      Queue_t *q = get(h);
+      del_elem(q);
     }
 }
 
@@ -225,7 +254,8 @@ void *ao_create_async(void *ao_device_yeah, void *ao_play_f)
     pthread_mutex_t m = PTHREAD_MUTEX_INITIALIZER;
     handle->mutex = m;
     pthread_create(&handle->thread, NULL, run, handle);
-    sem_init(&handle->queue_sem, 0, 0);
+    handle->queue_sem = (sem_t *) malloc(sizeof(sem_t));
+    sem_init(handle->queue_sem, 0, 0);
 #endif
 
 #ifdef USE_WINDOWS_THREADS