From: Yukihiro Matsumoto Date: 2008-11-03T09:04:37+09:00 Subject: [ruby-core:19676] Re: [Bug #703] string output duplication occurs if the same file descriptor written to in different threads Hi, In message "Re: [ruby-core:19668] [Bug #703] string output duplication occurs if the same file descriptor written to in different threads" on Sat, 1 Nov 2008 02:38:52 +0900, Roger Pack writes: |ruby-dev:32566 It's not related to ruby-dev:32566, I think. |a = Thread.new { p '4'} |b = Thread.new { p '3' } |a.join |b.join | |results in |"4" |"3" |"4" |"3" | |because the buffer is modified simultaneously by two threads within io_fflush [I think]. It doesn't happen on either trunk nor 1.8.7. What's your version, and platform? matz.