Linux下串口编程之二：读串口和写串口

1，打开串口
      /**打开串口，dev 串口设备名， mode 打开方式，**/
     int opendev(char *dev,mode_t mode)
    {
          int fd;
          fd = open(dev, mode);
          if (-1 == fd){   
                perror("Can't Open Serial Port");
                return -1; 
          }
          else{
                 fcntl(fd, F_SETFL, FNDELAY);
                 return fd;
          }
     }
2，写串口
    #define FALSE  -1
    #define TRUE   0
    #define NET_PORT 19988
    #define MAX_BUF_SIZE 4096
    struct net2net_buf{
           int len;
           char buf[MAX_BUF_SIZE];
     };
     #define RSDEV_NAME "/dev/ttyS1"
     int main(void)
     {
            int rsfd = 0;
            int nwrite;
            char input_buf[64];
            rsfd = opendev(RSDEV_NAME,O_RDWR | O_NOCTTY |