ret = read(socketFd, &frame, sizeof(struct can_frame)); if(ret < 0) { qDebug() << "CAN accept failure!"; } else if (ret < sizeof(frame)) { qDebug() << "CAN receive data is not long enough!"; } else if (frame.can_id & CAN_ERR_FLAG) { qDebug() << "CAN receive the frame error!"; } else { qtime->restart();
时间: 2024-02-10 10:33:15 浏览: 33
这段代码是用来接收 CAN 总线上的数据帧的,其中 socketFd 是指向 CAN 总线的套接字文件描述符,frame 是一个结构体,用来存储接收到的数据帧。代码中首先调用 read 函数来读取数据,如果返回值小于 0,说明读取失败;如果返回值小于 frame 的大小,说明接收到的数据不完整;如果数据帧的标识符中包含错误标志位,说明接收到的是错误帧;否则就重启一个计时器,并且可以对接收到的数据进行处理。其中 qtime 是一个 QTimer 对象,用来计时。
相关问题
ret = bind(socketFd, (struct sockaddr *)&addr, sizeof(addr));
这是使用 SocketCAN 接口进行 CAN 总线通信时的绑定操作,将 CAN 网络地址绑定到 Socket 上,以便进行数据的收发。
其中,`socketFd` 是之前通过 `socket` 函数创建的 Socket 文件描述符;`addr` 是 `sockaddr_can` 结构体类型的变量,包含了 CAN 网络地址信息;`sizeof(addr)` 是 `addr` 变量的字节大小。
该函数的返回值 `ret` 表示绑定是否成功,如果返回值为 0 表示成功,否则表示失败。
修改client.c: #include<stdio.h> #include<stdlib.h> #include<string.h> #include<errno.h> #include<sys/types.h> #include<sys/socket.h> #include<netinet/in.h> int main() { int ret = 0; int socket_fd; char buffer[100]="你好,我是xxx!"; struct sockaddr_in server_add; socket_fd = socket(AF_INET, SOCK_STREAM, 0); if(-1 == socket_fd) { printf("socket fail ! \r\n"); return -1; } bzero(&server_add,sizeof(struct sockaddr_in)); server_add.sin_family=AF_INET; server_add.sin_addr.s_addr= inet_addr("192.168.1.2"); server_add.sin_port=htons(8888); if(-1 == connect(socket_fd,(struct sockaddr *)(&server_add), sizeof(struct sockaddr))) { printf("connect fail !\r\n"); return -1; } ret = write(socket_fd, buffer, strlen(buffer)); if(-1 == ret ) { printf("write fail!\r\n"); return -1; } close(socket_fd); return 0; }server.c: #include<stdio.h> #include<stdlib.h> #include<string.h> #include<errno.h> #include<sys/types.h> #include<sys/socket.h> #include<netinet/in.h> int main() { int ret = 0; int socket_fd, new_socket_fd; struct sockaddr_in server_add,client_add; int add_len; char recv_buff[100]={0}; char send_buff[100]="朕xxx知道了!"; socket_fd = socket(AF_INET, SOCK_STREAM, 0); if(-1 == socket_fd) { printf("socket fail ! \r\n"); return -1; } bzero(&server_add,sizeof(struct sockaddr_in)); server_add.sin_family=AF_INET; server_add.sin_addr.s_addr=htonl(INADDR_ANY); server_add.sin_port=htons(8888); if(-1 == bind(socket_fd,(struct sockaddr *)(&server_add), sizeof(struct sockaddr))) { printf("bind fail !\r\n"); return -1; } if(-1 == listen(socket_fd,5)) { printf("listen fail !\r\n"); return -1; } while(1) { new_socket_fd = accept(socket_fd, (struct sockaddr *)(&client_add), &add_len); if(-1 == new_socket_fd) { printf("accept fail !\r\n"); return -1; } ret = read(new_socket_fd, recv_buff,100); if(-1 == ret) { printf("read data fail !\r\n"); return -1; } printf("Now we get:%s from client!\n", recv_buff); ret = write(socket_fd, send_buff, strlen(send_buff)); if(-1 == ret ) { printf("write fail!\r\n"); return -1; } close(new_socket_fd); } close(socket_fd); return 0; }修改服务器和客户端,使朕知道了正常输出
修改后的client.c:
```
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<errno.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
int main() {
int ret = 0;
int socket_fd;
char buffer[100]="你好,我是xxx!";
struct sockaddr_in server_add;
socket_fd = socket(AF_INET, SOCK_STREAM, 0);
if(-1 == socket_fd)
{
printf("socket fail ! \r\n");
return -1;
}
bzero(&server_add,sizeof(struct sockaddr_in));
server_add.sin_family=AF_INET;
server_add.sin_addr.s_addr= inet_addr("192.168.1.2");
server_add.sin_port=htons(8888);
if(-1 == connect(socket_fd,(struct sockaddr *)(&server_add), sizeof(struct sockaddr)))
{
printf("connect fail !\r\n");
return -1;
}
ret = write(socket_fd, buffer, strlen(buffer));
if(-1 == ret )
{
printf("write fail!\r\n");
return -1;
}
ret = read(socket_fd, buffer,100);
if(-1 == ret) {
printf("read data fail !\r\n");
return -1;
}
printf("Now we get:%s from server!\n", buffer);
close(socket_fd);
return 0;
}
```
修改后的server.c:
```
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<errno.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
int main() {
int ret = 0;
int socket_fd, new_socket_fd;
struct sockaddr_in server_add,client_add;
int add_len;
char recv_buff[100]={0};
char send_buff[100]="朕xxx知道了!";
socket_fd = socket(AF_INET, SOCK_STREAM, 0);
if(-1 == socket_fd) {
printf("socket fail ! \r\n");
return -1;
}
bzero(&server_add,sizeof(struct sockaddr_in));
server_add.sin_family=AF_INET;
server_add.sin_addr.s_addr=htonl(INADDR_ANY);
server_add.sin_port=htons(8888);
if(-1 == bind(socket_fd,(struct sockaddr *)(&server_add), sizeof(struct sockaddr))) {
printf("bind fail !\r\n");
return -1;
}
if(-1 == listen(socket_fd,5)) {
printf("listen fail !\r\n");
return -1;
}
while(1) {
new_socket_fd = accept(socket_fd, (struct sockaddr *)(&client_add), &add_len);
if(-1 == new_socket_fd) {
printf("accept fail !\r\n");
return -1;
}
ret = read(new_socket_fd, recv_buff,100);
if(-1 == ret) {
printf("read data fail !\r\n");
return -1;
}
printf("Now we get:%s from client!\n", recv_buff);
ret = write(new_socket_fd, send_buff, strlen(send_buff));
if(-1 == ret ) {
printf("write fail!\r\n");
return -1;
}
close(new_socket_fd);
}
close(socket_fd);
return 0;
}
```
在客户端发送消息后,服务器会返回“朕xxx知道了!”,客户端会输出“Now we get:朕xxx知道了! from server!”。