Looking more closely at your code above, there is something strange going on that I do not understand.

In this part of the main thread, you change the value of $ENV{TZ} twice: 

$ENV{TZ}="Europe/Paris";
my $t=localtime();
print "main (Europe/Paris): ",$t,"\n";

$ENV{TZ}="Europe/Moscow";
$t=localtime();
print "main (Europe/Moscow): ",$t,"\n";

[download]

But nowhere in that part of the code do you call tzset(), nor any of the functions in your XS code. And yet, according to the console output you've posted: 

main (Europe/Paris): Tue Nov 24 23:27:28 2009
main (Europe/Moscow): Wed Nov 25 01:27:28 2009

[download]

The output from localtime is somehow affected. Which is exactly what didn't happen originally that caused you to post your OP?

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
RIP PCW It is as I've been saying!(Audio until 20090817)

In reply to Re^4: Standard way to convert timezone in multithreaded script by BrowserUk
in thread Standard way to convert timezone in multithreaded script by whale2

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