in reply to Determining Daylight Savings Time

5. Reset $ENV{TZ} to its original value so it doesn't muck up any other date calculations elsewhere in the code

You could of course localize %ENV: 

{
    local $\ = "\n";
    print scalar localtime;
    {
        local %ENV;
        $ENV{TZ} = 'GMT';
        print scalar localtime;
    }
    print scalar localtime;
}

[download]
yields: 
Wed May 29 23:29:08 2002
Wed May 29 21:29:08 2002
Wed May 29 23:29:08 2002

[download]

Update/PS: -- for frontpaging your own node. Don't do that. 

- Yes, I reinvent wheels.
- Spam: Visit eurotraQ.

Replies are listed 'Best First'.
(MeowChow) Re2: Determining Daylight Savings Time
by MeowChow (Vicar) on May 30, 2002 at 19:49 UTC
    You don't have to localize all of %ENV: 
    local $ENV{TZ} = 'GMT';

    [download]
       MeowChow                                   
               s aamecha.s a..a\u$&owag.print
[reply]
[d/l]

      You don't have to localize all of %ENV: local $ENV{TZ} = 'GMT';

      Please test before posting. Localizing a single %ENV value will not work as expected. 

      {
    local $\ = "\n";
    print scalar localtime;
    {
        local $ENV{TZ} = 'GMT';
        print scalar localtime;
    }
    print scalar localtime, ", which is wrong.";
}

      [download]
      yields: 
      Thu May 30 23:19:56 2002
Thu May 30 21:19:56 2002
Thu May 30 21:19:56 2002, which is wrong.

      [download]
      Update: environment: Debian GNU/Linux sid x86, Perl 5.6.1 

      - Yes, I reinvent wheels.
- Spam: Visit eurotraQ.

[reply]
[d/l]
[select]
        It works on both my OpenBSD and Linux perl 5.6.1 and 5.00503. What platform are you testing on?
          
        {
    local $\ = "\n";
    print scalar localtime;
    {
        local $ENV{TZ} = 'GMT';
        print scalar localtime;
    }
    print scalar localtime, ", which is right.";
}

Thu May 30 16:36:26 2002
Thu May 30 21:36:26 2002
Thu May 30 16:36:26 2002, which is right.

        [download]
           MeowChow                                   
               s aamecha.s a..a\u$&owag.print
[reply]
[d/l]

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