1 #include <stdio.h> 2 #include <sys/stat.h> 3 #include <fcntl.h> 4 #include <unistd.h> 5  6 #define DEV_NAME "/dev/my_led" 7  8 int main(int argc, char const *argv[]) 9 {10     11     int  fd = open(DEV_NAME, O_RDWR);12     if(fd < 0) {13         perror("open");14         return -1;15     }16 17     char buf[10] = {0};18 19     int ret = read(fd, buf, 10);20     printf("buf = %s\n", buf); 21 22     close(fd);23     return 0;24 }