<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<style type="text/css" style="display:none;"> P {margin-top:0;margin-bottom:0;} </style>
</head>
<body dir="ltr">
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Hi:</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Recently, I wanted to write a program to watch the change of timezone database. I got newest version from this address: <a href="https://data.iana.org/time-zones/releases/tzdata2021a.tar.gz" id="LPlnk755185">https://data.iana.org/time-zones/releases/tzdata2021a.tar.gz</a>.
I used zic (version: zic (tzcode) 2020c, system: CentOS Linux release 7.6.1810 (Core)) to generate the zoneinfo. I pick up some zones with local timeto calculate utc time to verify the changes using both the new and currently used
<span style="background-color:rgb(255, 255, 255);display:inline !important">version </span>tzdata, here is diff:</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<table align="center" width="720" style="font-size:15px;font-family:"Microsoft Yahei UI", Verdana, Simsun, "Segoe UI", -apple-system, system-ui, Roboto, "Helvetica Neue", sans-serif;color:rgb(32, 31, 30);background-color:rgb(255, 255, 255);border-collapse:collapse">
<tbody>
<tr>
<td>zone</td>
<td>local time</td>
<td>by 2021a utc time</td>
<td>by 2020d utc time</td>
<td><br>
</td>
</tr>
<tr>
<td>America/Adak</td>
<td>2022-11-01 00:00:00</td>
<td>2022-11-01 09:00:00</td>
<td>2022-11-01 10:00:00</td>
<td><br>
</td>
</tr>
<tr>
<td>America/Anchorage</td>
<td>2022-11-01 00:00:00</td>
<td>2022-11-01 08:00:00</td>
<td>2022-11-01 09:00:00</td>
<td><br>
</td>
</tr>
<tr>
<td>America/Asuncion</td>
<td>2022-10-01 00:00:00</td>
<td>2022-10-01 04:00:00</td>
<td>2022-10-01 03:00:00</td>
<td><br>
</td>
</tr>
<tr>
<td>America/Atka</td>
<td>2022-11-01 00:00:00</td>
<td>2022-11-01 09:00:00</td>
<td>2022-11-01 10:00:00</td>
</tr>
</tbody>
</table>
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Those zones are not changed from version 2020d to 2021a. I am very confused and not sure if I generated the zoneinfo in the right way. Here was what do:</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
# mkdir zoneinfo</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
# cd tzdata2021a</div>
<div style=""><font color="#000000" face="Calibri, Arial, Helvetica, sans-serif"><span style="font-size: 12pt;"># zic -d ../</span></font><span style="background-color: rgb(255, 255, 255); display: inline !important;"><font color="#000000" face="Calibri, Arial, Helvetica, sans-serif"><span style="font-size: 12pt;">zoneinfo
-L </span></font><font color="#172b4d" face="-apple-system, system-ui, Segoe UI, Roboto, Oxygen, Ubuntu, Fira Sans, Droid Sans, Helvetica Neue, sans-serif"><span style="font-size: 14px;"> </span></font><span style="color: rgb(0, 0, 0); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;">./leapseconds
africa antarctica asia australasia europe northamerica southamerica etcetera backward factory</span><br>
</span></div>
<div style=""><br>
</div>
<div style=""><span style="background-color: rgb(255, 255, 255); display: inline !important;"><span style="color: rgb(0, 0, 0); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;">I was wondering if you could provide me some help. I really
appreciate your reply. </span><span style="color: rgb(0, 0, 0); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;"><br>
</span></span></div>
<div style=""><span style="background-color: rgb(255, 255, 255); display: inline !important;"><span style="color: rgb(0, 0, 0); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;"><br>
</span></span></div>
<div style=""><span style="background-color: rgb(255, 255, 255); display: inline !important;"><span style="color: rgb(0, 0, 0); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;"><span style="color:rgb(18, 18, 18);font-family:-apple-system, system-ui, "Helvetica Neue", "PingFang SC", "Microsoft YaHei", "Source Han Sans SC", "Noto Sans CJK SC", "WenQuanYi Micro Hei", sans-serif;font-size:15px;background-color:rgb(255, 255, 255);display:inline !important">Sincerely,</span><br>
</span></span></div>
<div style=""><span style="background-color: rgb(255, 255, 255); display: inline !important;"><span style="color: rgb(0, 0, 0); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;"><span style="color:rgb(18, 18, 18);font-family:-apple-system, system-ui, "Helvetica Neue", "PingFang SC", "Microsoft YaHei", "Source Han Sans SC", "Noto Sans CJK SC", "WenQuanYi Micro Hei", sans-serif;font-size:15px;background-color:rgb(255, 255, 255);display:inline !important">wangmm</span></span></span></div>
</body>
</html>