hi haskellers, have the issues with castIOUArray (and thus hGetArray, hPutArray) in Data.Array.IO discussed below been resolved? http://www.haskell.org/pipermail/libraries/2003-January/thread.html here is a (trivial) program which has rather unexpected behavior. (i'm switching to Data.Binary in the meantime.) import Data.Array.IO import System.IO (IOMode(..), openBinaryFile, hClose) dumpArray arr name = do h <- openBinaryFile name WriteMode w <- castIOUArray arr (l,u) <- getBounds w let len = u-1+1 hPutArray h w len hClose h return len loadArray name num = do arr <- newArray_ (1, num) h <- openBinaryFile name ReadMode read <- hGetArray h arr num if not(read == num) then error "Incorrect number of bytes read in from array!" else return arr len = 20 main = do arr <- newArray (1, len) 1::IO(IOUArray Int Int) size <- dumpArray arr "foo" arr2' <- loadArray "foo" size arr2 <- (castIOUArray arr2')::IO(IOUArray Int Int) e1 <- getElems arr e2 <- getElems arr2 print e1 print e2 print size print $ show (arr == arr2) best, b