C Typedef and Struct Question

Question

What's the difference between these two declarations, and is one preferred over the other?

typedef struct IOPORT {  
    GPIO_TypeDef* port;  
    u16           pin;  
} IOPORT;  

typedef struct {  
    GPIO_TypeDef* port;  
    u16           pin;  
} IOPORT;  

Answer 1

the first allows you to use IOPORT inside the struct for refering to objects of the same type. useful in cases such as linked lists where a node has to refer to a node.