宏定义时动态定义结构体

struct packet {
	char type;
};

#define TAILQ_HEAD(name, type)						\
struct name {								\
	struct type *tqh_first;	/* first element */			\
	struct type **tqh_last;	/* addr of last next element */		\
}

void test()
{
    TAILQ_HEAD(, packet) outgoing; //结构体的标签为NULL
    TAILQ_HEAD(xxx, packet) outgoing1; //结构体的标签为xxx
}