1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
|
-- !!! readFile test
import System.IO
import System.IO.Error
source = "readFile001.hs"
filename = "readFile001.out"
main = do
s <- readFile source
h <- openFile filename WriteMode
hPutStrLn h s
hClose h
s <- readFile filename
-- This open should fail, because the readFile hasn't been forced
-- and the file is therefore still locked.
tryIOError (openFile filename WriteMode) >>= print
putStrLn s
-- should be able to open it for writing now, because we've forced the
-- whole file.
h <- openFile filename WriteMode
print h
|
