头文件中结构体互相引用的问题

typedef struct _thread{
int       id;                        /* friendly id               */
pthread_t pthread;                   /* pointer to actual thread  */
thpool_handle_t thpool_p;            /* access to thpool          */
} thread_t;

/* Threadpool
* threadpool has many threads, and he should to access each threads, threads pointer array to save all threads pointer */
typedef struct _thpool{
thread_t**   threads;                  /* pointer to threads        */
volatile int num_threads_alive;      /* threads currently alive   */
volatile int num_threads_working;    /* threads currently working */
pthread_mutex_t  thcount_lock;       /* used for thread count etc */
jobqueue*  jobqueue_p;               /* pointer to the job queue  */
} thpool_t, *thpool_handle_t;

struct _thread;
struct _thpool;
typedef struct _thread thread_t;
typedef struct _thpool thpool_t, *thpool_handle_t;

typedef struct _thread{
int       id;                        /* friendly id               */
pthread_t pthread;                   /* pointer to actual thread  */
thpool_handle_t thpool_p;            /* access to thpool          */
} thread_t;

/* Threadpool
* threadpool has many threads, and he should to access each threads, threads pointer array to save all threads pointer */
typedef struct _thpool{
thread_t**   threads;                  /* pointer to threads        */
volatile int num_threads_alive;      /* threads currently alive   */
volatile int num_threads_working;    /* threads currently working */
pthread_mutex_t  thcount_lock;       /* used for thread count etc */
jobqueue*  jobqueue_p;               /* pointer to the job queue  */
} thpool_t, *thpool_handle_t;