包含函数指针的struct,其自身作为C中的返回类型

Question

得到以下数据结构:

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

结构中的最后一行应该是一个指向函数的指针,返回类型为void,指向事件的指针作为参数,例如:

void function(event *evt);

虽然,我得到以下警告信息:"它的范围只是这个定义或声明,可能不是你想要的".这是对还是错？

Answer 1

您的结构需要需要像这样定义:

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`