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

As far as which style is preferred, I prefer the 1st style (with the name in both the struct tag and as a typedef for the struct) simply because there are no drawbacks other than a few more characters in the source file. My IDE’s struct snippet drops the name in both places, so I always get a typedef’ed struct name along with a struct tag name.

You get a few small benefits:

• the “struct STRUCTNAME” can be used to declare pointers to the struct within the struct
• you can get away with just using STRUCTNAME in either C or C++ code
• you prevent a potential (even if very rare in practice) oddity in C++ having to do with the struct name being used for another object without error or warning

But, if I happen to manually type in the struct definition, I’ll often lazily neglect declaring one or the other name.