包含函数指针的struct，其自身作为C中的返回类型

Question

Got the following data struct:

typedef struct
{
    lamp *lamp;
    unsigned char a;
    unsigned char b;
    unsigned char c;
    unsigned char d;
    unsigned char e;
    void (*func)(struct event *);
} event;

The last line inside the struct is supposed to be a pointer to a function with return type void with pointer to an event as an argument such as:

void function(event *evt);

Though, I get the following warning message: "its scope is only this definition or declaration, which is probably not what you want". Is this right or wrong?

Answer 1

Your struct needs needs to be defined like this:

typedef struct event  // <<< note the `event` tag here
{
    lamp *lamp;
    unsigned char a;
    unsigned char b;
    unsigned char c;
    unsigned char d;
    unsigned char e;
    void (*func)(struct event *);
} event;              // <<< you can still keep `event` as a typedef
                      //     which is equivalent to `struct event`