function conf_append($file,$in,$top="<?php\r\n",$bottom=");?>")
{
 $ya=file_exists($file)?1:0;
 eval("if(\$ourfile=fopen(\$file,'".($ya?'r':'a')."+b'))
  {".($ya?"fseek(\$ourfile,-strlen(\$bottom),SEEK_END);":"")."
  fwrite(\$ourfile,".(!$ya?"\$top.":"")."\$in.\$bottom);
  fclose(\$ourfile);}");
}
  We can't change pointer file position when we open it 
with 'a+', but may when 'r+'/ So we need for create open with 'a+', and if file exists 'r+'