Hi Daniel, On 09.10.2011, at 14:45, Daniel Fischer wrote:
On Sunday 09 October 2011, 13:52:47, Jean-Marie Gaillourdet wrote:
This seems to be a Heisenbug as it is extremely fragile, when adding a "| grep 1" to the while loop it seems to disappears. At least on my computers.
Still produces 1s here with a grep.
Well, it may have been bad luck on my site.
All this was done on several Macs running the latest OS X Lion with ghc 7.0.3 from the binary distribution on the GHC download page.
linux x86_64, ghc-7.0.4, 7.0.2 and 6.12.3. Indeed 6.12.3 goes so far to sometimes produce 0 0 --- 10
--- 0 0 --- 01
---
i.e. it switches threads during print.
Thanks, for reproducing it. I failed to see it on Linux so far. So I guess a bug report is in order? Or are bug reports to old versions not welcome? Jean