1 typedef struct Queue Queue; 2 Queue *_vtqalloc(void); 3 int _vtqsend(Queue*, void*); 4 void *_vtqrecv(Queue*); 5 void _vtqhangup(Queue*); 6 void *_vtnbqrecv(Queue*); 7 void _vtqdecref(Queue*); 8 Queue *_vtqincref(Queue*);