queryFdOption broken

Hi,

While writing a testcase for another bug (details to follow), I found
that System.Posix.IO.queryFdOption doesn't work.

The problem appears to be that queryFdOption uses testBit incorrectly;
it assumes the second argument is the bitmask, when it's actually the
bit *position* to test. It should be an easy fix (just do a bitwise AND
and see whether the result's zero instead).

Here's how to reproduce the problem on my system -- note that it's
getting the correct results from the underlying system calls, but not
returning them correctly:

$ ghc --version
The Glorious Glasgow Haskell Compilation System, version 6.4
$ uname -a
Linux cartman.at.fivegeeks.net 2.6.12.2 #1 Thu Jul 14 15:28:07 BST 2005
i686 unknown unknown GNU/Linux
$ gcc -v
Reading specs from
/opt/packages/gcc-3.4.4/bin/../lib/gcc/i686-pc-linux-gnu/3.4.4/specs
Configured with: ./configure --prefix=/opt --sysconfdir=/etc
--localstatedir=/var --sharedstatedir=/var/com --enable-__cxa_atexit
--enable-threads=posix --enable-shared
--enable-languages=c,c++,java,f77,objc
Thread model: posix
gcc version 3.4.4
$ cat Query.hs
import System.Posix.IO

showNBR = do
        v <- System.Posix.IO.queryFdOption 0
System.Posix.IO.NonBlockingRead
        putStr $ "NonBlockingRead = " ++ (show v) ++ "\n"

main = do
        showNBR
        System.Posix.IO.setFdOption 0 System.Posix.IO.NonBlockingRead
True
        showNBR
$ ghc -o query -package unix Query.hs 
$ ./query
NonBlockingRead = False
NonBlockingRead = False
$ strace ./query 2>&1 | grep ETFL
[...]
fcntl64(0, F_GETFL)                     = 0x2 (flags O_RDWR)
fcntl64(0, F_SETFL, O_RDWR|O_NONBLOCK)  = 0
fcntl64(0, F_GETFL)                     = 0x802 (flags O_RDWR|O_NONBLOCK)
[...]

If you need any more information, please let me know.

Thanks,

-- 
Adam Sampson <ats@xxxxxxxxx>                         <http://offog.org/>