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Date: | Mon, 10 Dec 2007 17:00:52 -0500 |
From: | "Jerry D. Hedden" <jdhedden AT cpan DOT org> |
To: | cygwin AT cygwin DOT com |
Subject: | BUG: Timezone failures with threads under Cygwin 1.5.25 |
Cc: | pp <perl5-porters AT perl DOT org> |
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(CC'ed to perl5-porters for reference.) The Perl test suite contains a file (perl-current/ext/threads/t/libc.t) that exercises the 'localtime' call under threads. Here's the main code: my $i = 10; my $y = 20000; my %localtime; for (1..$i) { $localtime{$_} = localtime($_); }; my @threads; for (1..$i) { $threads[$_] = threads->create(sub { my $arg = shift; my $localtime = $localtime{$arg}; my $error = 0; for (1..$y) { my $lt = localtime($arg); if ($localtime ne $lt) { $error++; } } return $error; }, $_); } for (1..$i) { is($threads[$_]->join(), 0, 'localtime() thread-safe'); } This runs 10 threads that call 'localtime' 20,000 times each. Under 1.5.24, this test always passes. Under 1.5.25, it is now frequently failing. If I add a debugging call in the central most loop: print("got: $lt exp: $localtime\n"); I get the following as typical of the problem: 5 perl-current > ./perl -Ilib ext/threads/t/libc.t 1..11 ok 1 - use threads got: Wed Dec 31 20:00:08 1969 exp: Wed Dec 31 19:00:08 1969 got: Wed Dec 31 20:00:07 1969 exp: Wed Dec 31 19:00:07 1969 got: Wed Dec 31 20:00:06 1969 exp: Wed Dec 31 19:00:06 1969 got: Wed Dec 31 20:00:08 1969 exp: Wed Dec 31 19:00:08 1969 got: Wed Dec 31 20:00:07 1969 exp: Wed Dec 31 19:00:07 1969 got: Wed Dec 31 20:00:06 1969 exp: Wed Dec 31 19:00:06 1969 got: Wed Dec 31 20:00:10 1969 exp: Wed Dec 31 19:00:10 1969 ok 2 - localtime() thread-safe ok 3 - localtime() thread-safe ok 4 - localtime() thread-safe ok 5 - localtime() thread-safe ok 6 - localtime() thread-safe not ok 7 - localtime() thread-safe # Failed at ext/threads/t/libc.t line 52 # got '2' # expected '0' not ok 8 - localtime() thread-safe # Failed at ext/threads/t/libc.t line 52 # got '2' # expected '0' not ok 9 - localtime() thread-safe # Failed at ext/threads/t/libc.t line 52 # got '2' # expected '0' ok 10 - localtime() thread-safe not ok 11 - localtime() thread-safe # Failed at ext/threads/t/libc.t line 52 # got '1' # expected '0' This shows a 1 hour difference between the expected and actual results - which looks like a timezone issue. As the changes for 1.5.25 include numerous references to timezone handling changes, I suspect there may be some re-entrancy bug in those changes. -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
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