求助，这个报错是为什么

Question

#include "canthread.h"
#include "communication/uartandcanshare.h"

#include <sys/socket.h>
#include <linux/can.h>//对应头文件
#include <net/if.h>
#include <sys/ioctl.h>
#include <linux/can/raw.h>
#include <errno.h>
#include <getopt.h>
#include <unistd.h>

#define BUF_SIZ (255)
#define myerr(str)    fprintf(stderr, "%s, %s, %d: %s\n", __FILE__, __func__, __LINE__, str)

canThread *canThread::m_canthread = NULL;

canThread::canThread(QObject *parent):
    QThread(parent)
{
#if 1
    struct sockaddr_can addr;  //此处报错
    struct ifreq ifr;

    int canfd;
    canfd = socket(PF_CAN, SOCK_RAW, CAN_RAW);
    if(canfd == -1)
    {
        perror("Socket failed");
        exit(1);
    }
        ...
}

报错内容：
/opt/code/Bartack/src/communication/canthread.cpp:26: error: aggregate 'canThread::canThread(QObject*)::sockaddr_can addr' has incomplete type and cannot be defined
struct sockaddr_can addr;
^

头文件已经包含了，实在想不出为什么会这样，求助，求助，求助

Answer 1

类型不完整，不能定义结构；
#include int main () {
/* 定义不完整结构类型 /
struct user;
/ 可以定义指向不完整结构类型的指针 /
struct user *p;
/ 补充结构定义 /
struct user { char *name; int age; };
/ 只有完整的结构类型可以定义变量 /
struct user qifei; qifei.name = "qifei"; qifei.age = 28;
p = &qifei; printf("user name:%s/n", p->name);
printf("user age :%d/n", p->age); return 0; }
*参考下**