char *get_RFC1123date(long *date) {

  char D[STRLEN];
  time_t now= (date && (*date>0))?*date:time(&now);
  long timezone_h;
  long timezone_m;
  int datelen;

  time(&now);
  tzset();

  timezone_h= -(timezone/3600)+daylight;
  timezone_m= abs(timezone/60)%60;

  datelen=strftime(D, STRLEN-7, "%a, %d %b %Y %H:%M:%S", localtime(&now));

  if ( ! datelen ) {

    memset(D, 0, STRLEN);
               
  } else {
   
    snprintf(D+datelen, 7, " %+03ld%02ld", timezone_h, timezone_m);

  }

  return xstrdup(D);
}