File: openFile005.hs

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-- !!! test multiple-reader single-writer locking semantics

import System.IO
import System.IO.Error

file1 = "openFile005.out1"
file2 = "openFile005.out2"

main = do
  putStrLn "two writes (should fail)"
  h <- openFile file1 WriteMode
  tryIOError (openFile file1 WriteMode) >>= print
  hClose h

  putStrLn "write and an append (should fail)"
  h <- openFile file1 WriteMode
  tryIOError (openFile file1 AppendMode) >>= print
  hClose h

  putStrLn "read/write and a write (should fail)"
  h <- openFile file1 ReadWriteMode
  tryIOError (openFile file1 WriteMode) >>= print
  hClose h

  putStrLn "read and a read/write (should fail)"
  h <- openFile file1 ReadMode
  tryIOError (openFile file1 ReadWriteMode) >>= print
  hClose h

  putStrLn "write and a read (should fail)"
  h <- openFile file1 WriteMode
  tryIOError (openFile file1 ReadMode) >>= print
  hClose h

  putStrLn "two writes, different files (silly, but should succeed)"
  h1 <- openFile file1 WriteMode
  h2 <- openFile file2 WriteMode
  hClose h1
  hClose h2

  putStrLn "two reads, should succeed"
  h1 <- openFile file1 ReadMode
  h2 <- openFile file1 ReadMode
  hClose h1
  hClose h2