feof函数返回值始终是零？？？？？？？？？？？？？？？？？？？？？？？

Question

                    while (!feof(openfile))
                    {
                        str = fgetc(openfile);
                        str = str + '\10';
                        fputc(str, openfile);
                        printf("%c", str);
                        if (ferror(openfile))
                        {
                            perror("Read error");
                            break;
                        }
                        a = feof(openfile);
                        printf("%d",a );
                    }

Answer 1

http://www.cnblogs.com/ayanmw/archive/2012/09/12/2682016.html