There are some extensive comments in Piece.xs about the CRT, the environment (especially $ENV{TZ}) and tzset - specifically: 
 * Therefore, we need to retrieve the value of $ENV{TZ} and call CRT
 * putenv() to update the CRT copy of the environment (if it is differ
+ent)
 * whenever we're about to call tzset().

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And the 2 failing tests I get when I "mix runtimes" come from: 
SKIP: {
    skip "can't register TZ changes in a pseudo-fork", 2 if $is_pseudo
+_fork;
    local $ENV{TZ} = "EST5";
    Time::Piece::_tzset();  # register the environment change
    my $lt = localtime;
    cmp_ok(scalar($lt->tzoffset), 'eq', '-18000');
    cmp_ok($lt->strftime("%Z"), 'eq', 'EST');
}

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I expect that when Time::Piece is built with a compiler that uses a different runtime, Time::Piece::_tzset() registers the environment change ok, but registers it with the *wrong* runtime (for the purposes of Time::Piece, at least).

Not sure how this could be fixed. With which runtime will Time::Piece::_tzset() register the change ?
With the runtime of the compiler that built perl ? ... or with the runtime of the compiler that built Time::Piece ?
I suspect it must be the latter, and the trick would be to get Time::Piece::_tzset() to register the change with the former. (Or vice-versa :-)

Cheers,
Rob

In reply to Re^9: Testing Time::Piece on Windows/VC by syphilis
in thread Testing Time::Piece on Windows/VC by Corion

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