Hi, I am reading data from a file as strict bytestrings and processing them in an iteratee. As the parsing code uses Data.Binary, the strict bytestrings are then converted to lazy bytestrings (using fromWrap which Gregory Collins posted here in January: -- | wrapped bytestring -> lazy bytestring fromWrap :: I.WrappedByteString Word8 -> L.ByteString fromWrap = L.fromChunks . (:[]) . I.unWrap ). The parsing is then done with the library function Data.Binary.Get.runGetState: -- | Run the Get monad applies a 'get'-based parser on the input -- ByteString. Additional to the result of get it returns the number of -- consumed bytes and the rest of the input. runGetState :: Get a -> L.ByteString -> Int64 -> (a, L.ByteString, Int64) The issue I am seeing is that runGetState consumes more bytes than the length of the input bytestring, while reporting an apparently successful get (ie. it does not call error/fail). I was able to work around this by checking if the bytes consumed > input length, and if so to ignore the result of get and simply prepend the input bytestring to the next chunk in the continuation. However I am curious as to why this apparent lack of bounds checking happens. My guess is that Get does not check the length of the input bytestring, perhaps to avoid forcing lazy bytestring inputs; does that make sense? Would a better long-term solution be to use a strict-bytestring binary parser (like cereal)? So far I've avoided that as there is not yet a corresponding ieee754 parser. Conrad.