[Haskell-cafe] trying to use unix's openFD ..

Galchin Vasili vigalchin at gmail.com
Wed Jan 30 23:23:59 EST 2008


I am trying to do the following on RedHat RHEL 5.0:

main = do
    fs <- openFd "/dev/cdrom" ReadOnly (Just ???) defaultFileFlags
    putStrLn (show fd)

what should (Just ???) be ???

Regards, Vasili

On Jan 30, 2008 11:10 PM, Brandon S. Allbery KF8NH <allbery at ece.cmu.edu>
wrote:

>
> On Jan 30, 2008, at 23:05 , Galchin Vasili wrote:
>
> > Hello,
> >
> >        The signature for openFD is
> >
> > openFd: FilePath
> >             -> OpenMode
> >             -> Maybe FileMode
> >             -> OpenFileFlags
> >             -> IO Fd
> >
> > I am currently reading http://www.haskell.org/ghc/docs/latest/html/
> > libraries/unix/System-Posix-Files.html  and diving down into links
> > but can't find the definition of data type FileMode. ??? Basically
> > I want to open in O_RDONLY filemode.
>
> That's an OpenMode, not a FileMode.  The FileMode values are at the
> top of System-Posix-Files.html and correspond to Unix open()'s third
> argument.  (ownerReadMode, etc.)  OpenMode is documented at the start
> of http://www.haskell.org/ghc/docs/latest/html/libraries/unix/System-
> Posix-IO.html .
>
> --
> brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery at kf8nh.com
> system administrator [openafs,heimdal,too many hats] allbery at ece.cmu.edu
> electrical and computer engineering, carnegie mellon university    KF8NH
>
>
>
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