<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="Generator" content="Microsoft Word 15 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman",serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p.msonormal0, li.msonormal0, div.msonormal0
{mso-style-name:msonormal;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:12.0pt;
font-family:"Times New Roman",serif;}
span.EmailStyle18
{mso-style-type:personal-reply;
font-family:"Calibri",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-US" link="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">FYI: on Windows 32-bit builds CAN use 64-bit timestamps (by using USE_32BIT_TIME_T macro, see https://msdn.microsoft.com/en-us/library/1f4c8f33.aspx). As far as I know, this
is not possible on *NIX (my knowledge is limited to Solaris/AIX/HPUX/Linux). I don’t understand how 32-bit time_t systems can survive 2038 and beyond. I’m not sure what this will mean for embedded systems (with e.g. Linux), where 32-bit is still very common.
That systems then also should have a 64-bit representation for time_t?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Arthur David Olson [mailto:arthurdavidolson@gmail.com]
<br>
<b>Sent:</b> Wednesday, January 11, 2017 23:06<br>
<b>To:</b> Paul Eggert <eggert@cs.ucla.edu><br>
<b>Cc:</b> Kees Dekker <Kees.Dekker@infor.com>; Time Zone Mailing List <tz@iana.org><br>
<b>Subject:</b> Re: [tz] question about mktime_tzname()<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<div>
<div>
<p class="MsoNormal" style="margin-bottom:12.0pt">> Unfortunately now that I think of it, I see that this can't work on<br>
> hosts with 32-bit time_t, as they can't cover the 400-year span. So the<br>
> code is still broken on 32-bit hosts. Is there a better way to fix the code?<o:p></o:p></p>
</div>
<p class="MsoNormal" style="margin-bottom:12.0pt">Since 32-bit time_t values can only cover (about) 140 years, not covering a 400-year span's not a bug, it's a given.-)<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">(An aside: in the future, my guess is that there'll either be a new, 64-bit-only time zone binary format or that time zone source will be interpreted at run time with no binary format; at that point, a lot of code simplification happens.)<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<p class="MsoNormal"> @dashdashado<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<p class="MsoNormal">On Wed, Jan 11, 2017 at 4:51 PM, Paul Eggert <<a href="mailto:eggert@cs.ucla.edu" target="_blank">eggert@cs.ucla.edu</a>> wrote:<o:p></o:p></p>
<blockquote style="border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in">
<p class="MsoNormal" style="margin-bottom:12.0pt">On 01/11/2017 01:28 PM, Arthur David Olson wrote:<br>
> When a table generated from an environment variable does indeed cover<br>
> 400 years, both goahead and goback should be set.<br>
<br>
The localtime.c code in question tries to do that sort of thing, as it says:<br>
<br>
yearlim = EPOCH_YEAR + YEARSPERREPEAT;<br>
for (year = EPOCH_YEAR; year < yearlim; year++) {<br>
<br>
and YEARSPERREPEAT is 400.<br>
<br>
Unfortunately now that I think of it, I see that this can't work on<br>
hosts with 32-bit time_t, as they can't cover the 400-year span. So the<br>
code is still broken on 32-bit hosts. Is there a better way to fix the code?<br>
<br>
Also, I'm puzzled as to why the first transition in 1970 was being<br>
omitted, as that leads me to worry that the above code will generate one<br>
transition shy of 400 years' worth even on 64-bit hosts.<o:p></o:p></p>
</blockquote>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
</div>
</body>
</html>