/* get current time using format */
_gdttfmt(f, prec)
{
        local t, fmt, oprec;

        prec = caststring(prec);

        oprec = getconf("time_precision");
        fmt = getconf("dt_time_format");
        setconf("time_precision", prec);
        setconf("dt_time_format", caststring(f));
        t = gettime();
        setconf("time_precision", oprec);
        setconf("dt_time_format", fmt);
        return(t);

}