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1 | The following information about Perl and the year 2000 is a modified |
2 | version of the information that can be found in the Frequently Asked | |
3 | Question (FAQ) documents. | |
4 | ||
5 | Does Perl have a year 2000 problem? Is Perl Y2K compliant? | |
6 | ||
7 | Short answer: No, Perl does not have a year 2000 problem. Yes, | |
8 | Perl is Y2K compliant (whatever that means). The | |
9 | programmers you've hired to use it, however, probably are | |
10 | not. If you want perl to complain when your programmers | |
11 | create programs with certain types of possible year 2000 | |
12 | problems, a build option allows you to turn on warnings. | |
13 | ||
14 | Long answer: The question belies a true understanding of the | |
15 | issue. Perl is just as Y2K compliant as your pencil | |
16 | --no more, and no less. Can you use your pencil to write | |
17 | a non-Y2K-compliant memo? Of course you can. Is that | |
18 | the pencil's fault? Of course it isn't. | |
19 | ||
20 | The date and time functions supplied with perl (gmtime and | |
21 | localtime) supply adequate information to determine the | |
22 | year well beyond 2000 (2038 is when trouble strikes for | |
23 | 32-bit machines). The year returned by these functions | |
0139fc7d | 24 | when used in a list context is the year minus 1900. For |
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25 | years between 1910 and 1999 this happens to be a 2-digit |
26 | decimal number. To avoid the year 2000 problem simply do | |
27 | not treat the year as a 2-digit number. It isn't. | |
28 | ||
29 | When gmtime() and localtime() are used in scalar context | |
30 | they return a timestamp string that contains a fully- | |
31 | expanded year. For example, $timestamp = | |
32 | gmtime(1005613200) sets $timestamp to "Tue Nov 13 01:00:00 | |
33 | 2001". There's no year 2000 problem here. | |
34 | ||
35 | That doesn't mean that Perl can't be used to create non- | |
36 | Y2K compliant programs. It can. But so can your pencil. | |
37 | It's the fault of the user, not the language. At the risk | |
38 | of inflaming the NRA: ``Perl doesn't break Y2K, people | |
39 | do.'' See http://language.perl.com/news/y2k.html for a | |
40 | longer exposition. | |
41 | ||
42 | If you want perl to warn you when it sees a program which | |
43 | catenates a number with the string "19" -- a common | |
44 | indication of a year 2000 problem -- build perl using the | |
45 | Configure option "-Accflags=-DPERL_Y2KWARN". | |
46 | (See the file INSTALL for more information about building | |
47 | perl.) |