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