[Haskell] Foreign.Marshal.Alloc questions

For the allocation functions in Foreign.Marshall.Alloc, are the function contracts that return new pointers such that the pointers are never nullPtr, or is it prudent to always check the new ptr? I can see on GHC than allocaBytes uses newPinnedByteArray# but I have not tracked down the source file for that to read it. -- Chris Kuklewicz