#include <stdio.h>#include <stdlib.h>#include <string.h>int main(int argc, char **argv){   int fd,i;            char temp[20];    printf("-user test program-\n");	    FILE *f_op=fopen("/dev/my_devfs","r");   if(f_op == NULL)     printf("open error!!!\n");          i=fread(temp,sizeof(temp),1,f_op);           printf("i: %d\n",i);        printf("read: %s\n",temp);     fclose(f_op);  return 0;	}