From bug-octave-request at bevo dot che dot wisc dot edu  Wed Jan 20 00:07:59 1999
Subject: localtime(t) and gmtime(t) get wrong answers if t's fraction is >= 0.5
From: Samsung Lim <slim at inha dot ac dot kr>
To: bug-octave at bevo dot che dot wisc dot edu
Date: Wed, 20 Jan 1999 15:06:35 +0900

Bug report for Octave 2.0.13 configured for sparc-sun-solaris2.5.1

Description:
-----------

 In Octave, localtime(t) and gmtime(t) get wrong answers if t's
    fraction is greater than or equal to 0.5. In that case, "sec" is
    rounded up, while "usec" exactly corresponds to the fractional part.

    Consequently, mktime(localtime(t))==t turns out to be false (0).
Some
    example is given at the end of the description. It sure is wrong,
    but this is a delicate problem because it may not be wrong for
    someone who needs only "sec" not "usec". Anyway, this error comes
    from the "src/time.cc". The following is a part of "localtime"
    definition. I think "NINT (tmp)" has to be "int (tmp)".

### BEGIN CODE ###
DEFUN_DLD (localtime, args, ,

... snipped ...

      if (! error_state)
        {
          time_t timeval = NINT (tmp);
          double ip;
          double fraction = modf (tmp, &ip);

          retval = octave_value (mk_tm_map (localtime (&timeval),
fraction));
        }

... snipped again ...
### END CODE ###

octave:1> lt=localtime(t=916802834.5)
lt =
{
  usec = 500000
  year = 99
  mon = 0
  mday = 20
  sec = 15 <================ shouldn't it be 14?
  zone = KST
  min = 27
  wday = 3
  hour = 12
  isdst = 0
  yday = 19
}

octave:2> mktime(lt)==t
ans = 0

Fix:
---

### BEGIN CODE ###
DEFUN_DLD (localtime, args, ,

... snipped ...

      if (! error_state)
        {
          time_t timeval = int (tmp);
          double ip;
          double fraction = modf (tmp, &ip);

          retval = octave_value (mk_tm_map (localtime (&timeval),
fraction));
        }

... snipped again ...
### END CODE ###