<html xmlns="http://www.w3.org/1999/xhtml"><head></head><body><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="5" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[5]</anchor-end> <dfn><code>DateTime</code></dfn> は、<anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">日時</anchor>を扱う <anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">Perlモジュール</anchor>です。</p><refs xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:"><ul xmlns="http://www.w3.org/1999/xhtml"><li><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="9" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[9]</anchor-end> <cite>DateTime - A date and time object for Perl - metacpan.org</cite> (<time>2019-06-10 09:38:02 +09:00</time>) <anchor-external xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resScheme="URI" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resParameter="https://metacpan.org/pod/DateTime">https://metacpan.org/pod/DateTime</anchor-external></li><li><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="11" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[11]</anchor-end> <cite xml:lang="en">houseabsolute/<anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">DateTime.pm</anchor>: A date and time object for Perl</cite> (<time>2019-06-10 09:56:18 +09:00</time>) <anchor-external xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resScheme="URI" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resParameter="https://github.com/houseabsolute/DateTime.pm">https://github.com/houseabsolute/DateTime.pm</anchor-external></li></ul></refs><section><h1>メモ</h1><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="10" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[10]</anchor-end> <cite>Perl DateTime Project</cite>,
<anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">Dave Rolsky</anchor>,
<time>March 30, 2006<attrvalue xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:10:">2006-03-30</attrvalue></time>
(<time>2019-06-10 09:43:04 +09:00</time>) <anchor-external xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resScheme="URI" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resParameter="https://web.archive.org/web/20090917152516/http://www.houseabsolute.com/presentations/perl-datetime-project-tokyo/">https://web.archive.org/web/20090917152516/http://www.houseabsolute.com/presentations/perl-datetime-project-tokyo/</anchor-external>
(<anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">スペースキー</anchor>で次ページに進む)</p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="6" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[6]</anchor-end> <anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">日時を扱うPerlモジュール<title xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:10:">Perlにおける日時</title></anchor>の大本命として注目されていました。</p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="7" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[7]</anchor-end> <anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">モダンPerl</anchor>主義者などに支持されてよく使われる一方で、
重厚長大で細かい気が利かず使いづらいなどと嫌う人もいます。</p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="1" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[1]</anchor-end> <anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">Perl 5.10</anchor> でも<anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">標準モジュール</anchor>ではないみたいです。</p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="2" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[2]</anchor-end> <anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">閏秒</anchor>に対応しています。</p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="3" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[3]</anchor-end> <anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">time_t</anchor> で表せない昔や将来の<anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">日時</anchor>に対応しています。</p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="4" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[4]</anchor-end> <anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">秒の小数部</anchor>にも対応しています。 (<anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">ナノ秒</anchor>で指定できます。それが最小単位っぽいです。)</p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="8" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[8]</anchor-end> あまりに大きな<anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">年</anchor>を与えると、<anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">夏時刻</anchor>の計算に異常な時間がかかる問題が知られています。
<sw-see xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:"> <anchor>日時計算ソフトウェアのパフォーマンス問題</anchor> </sw-see></p></section></body></html>