[Haskell-cafe] catting to cat gets stuck at > 135K
jason.dusek at gmail.com
Mon Nov 10 16:29:36 EST 2008
I've put together a simple test case for a rather annoying
problem. I've got a program that drives other programs. For
example, it can drive `cat`:
:; Simple cat a-file
When the file is a little bit greater than 135060 bytes, this
program fails to produce any output at all -- I need to use ^C
to get my console back.
I have a similar program that encounters the same issue a
little after 139192 bytes. The inconsistency is one baffling
feature of this bug.
If I remove the `hClose`, the example program just hangs, no
matter the size of the input.
It is entirely possible that I have overlooked some subtle
feature of pipe semantics -- indeed, I hope that is the case.
import System.IO (hClose)
import Prelude hiding (writeFile, readFile)
main = do
exe:file:_ <- getArgs
bytes <- readFile file
foo <- simple exe bytes 
writeFile (file ++ ".foo") foo
-- Manufactures a simple stream handler from a command line utility.
:: String -> ByteString -> [String] -> IO ByteString
simple exe bytes args = do
(i, o, e, p) <- runInteractiveProcess exe args Nothing Nothing
hPut i bytes
s <- hGetContents o
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