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Summary

File reads/writes bigger than 2GB result in an "Invalid argument" exception on macOS. Files bigger than 2GB still work, but individual read/write operations bigger than 2GB fail.

This was already reported for the bytestring library, but the actual problem is in base. I didn't see an earlier report.

bytestring report: https://github.com/haskell/bytestring/issues/153

Python has a workaround for this issue and more discussion: https://bugs.python.org/issue24658

Steps to reproduce

{-# LANGUAGE ScopedTypeVariables #-}
import Foreign.Ptr (Ptr)
import Foreign.Marshal.Alloc (mallocBytes, free)
import System.IO (hPutBuf, withBinaryFile, IOMode (WriteMode)) 

-- more than 2GiB
numBytes :: Int
numBytes = 2264375889

main :: IO ()
main = do
  (ptr :: Ptr ()) <- mallocBytes numBytes
  -- the next line produces the exception on macOS
  withBinaryFile "test.out" WriteMode (\h -> hPutBuf h ptr numBytes)
  free ptr

Expected behavior

The base library provides operating system independent buffering and encoding functionality. I think it should work around operating system peculiarities and write all the data to the test.out file without throwing an excepion.

Environment

Tested with GHC 8.6.5 on macOS 10.14.6