On Tue, Jul 19, 2011 at 11:14 PM, yi huang <yi.codepla...@gmail.com> wrote: > 2011/7/20 Eugene Kirpichov <ekirpic...@gmail.com> >> >> reallyUnsafePointerEq#, and it really is as unsafe as it sounds :) >> > Why is it so unsafe? i can't find any documentation on it. > I think always compare pointer first is a good optimization.
False positives and false negatives are both possible, depending on GC timing. Don't use it, unless you know why it can result in both false positives and false negatives, and you know why neither of those are bad for your use case. I'm not aware of any use case that's resilient to both failure modes, offhand. Carl _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
