Hi John, I am reading your RSA code as suggested. 1) Do you have an example code that uses your RSA API? 2) a ForeignPtr is created in function createPkey and "returned" to the caller. I am trying to follow which function(s) GC the associated heap. ?? 3) My assertion: It seems in my Posix asynch IO case ... that functions like aioRead, aioWrite, lioListIO would create ForeignPtrs that would "carried around in the AIO application and the associated heap would only be GC'd (garbage collected) when aioReturn or aio_Cancel get called. True? Kind regards, Vasili