I am trying to dynamically load a shared haskell module - and it almost works... however as soon as the grabage collector thread runs it frees/moves something and the program falls over. Presumably this means I need to use a StablePtr - however I have as yet been unable to work out what exactly is the cause. I was hoping somebody with some knowledge of th einternals of GHC could help me out... The summary of what happens is: using FFI to call libdl on linux: - load module using dlopen (the library is compiled with -optl -shared and the loader is compiled with -rdynamic, so after loading all static symbols should be resolved.) - using dlsym to get a FunPtr to a module initialiser. - passing a StablePtr to a (FiniteMap String (SomeFunction)) as well as a dynamically exported continuation function (ie a "main-loop") which takes the FiniteMap as an argument to the initialiser. (now in the loaded module) - de-reference FiniteMap StablePtr, and add a handler function and string-identifier using addToFM, then create a newStablePtr to the modified FiniteMap and call the dynamic imported main-loop fn with FiniteMap as argument. - main loop calls back to module at a later time - dependant on string identifier. when I run this with +RTS -B it successfully loads, links and calls back 3 or 4 times, then goes 'beep' and dies - I think in the garbage collector thread itself, or as soon as the GC finishes. Any info that would shed light on what is happening would be useful. Regards, Keean Schupke.