On Wed, May 8, 2013 at 8:12 PM, Jason Dagit <dag...@gmail.com> wrote: > On Wed, May 8, 2013 at 6:54 PM, Niklas Hambüchen <m...@nh2.me> wrote: >> I have an annoying bug in a C binding that can be triggered like this: >> >> >> handle <- open ... >> >> prep <- makePreparedStatement handle "INSERT ..." >> >> performGC >> >> runStatement prep >> >> close handle >> >> If I run these steps one by one in ghci, garbage ends up in my handle as >> expected. >> >> However, if I "let main = do ..." this whole block in order to pack it >> in a test case, it does not happen, neither in ghci nor ghc. >> >> What might be the special magic in ghci's REPL that allows me to trigger >> my bug so easily there? > > One thing to investigate: Thread Local Storage > > By default ghci puts each action you run into a thread and executes > it. If the underlying C code stores something (or accesses it) from > thread local storage, then you will run into issues like this.
My point was meant to be, it's something to try but I have no idea if it's going to be the issue here. The caveat I forgot to add is: I've never seen the thread local storage issue affect GC. In particular, ghc might be running a finalizer in the case of individual actions because it doesn't know you are about to use the handle? Now that I think about it more, I suspect that is more likely to be the case. Jason _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
