[Haskell-cafe] Hoogle

[John Goerzen]

On Wednesday 16 April 2008 6:16:56 pm Brandon S. Allbery KF8NH wrote:
> On Apr 16, 2008, at 17:30 , John Goerzen wrote:
> > On Wed April 16 2008 3:54:45 pm Galchin, Vasili wrote:
> >>    I already found this link. Thanks in any case. I want to
> >> O_CREATE a
> >> file, i.e. do a openFd creating a new file. O_CREATE should be the
> >> FileMode, but I don't see in the link below.
> >
> > Indeed.  It seems there is no way to pass O_CREAT to openFile.
> > there is
> > createFile, but that's really a different call.  Sigh.
>
> Remember, Haskell is functional; treat the function to call as an
> argument?

I don't have access to the GHC source just at the moment, but presumably that 
is an interface to creat() instead of open().  creat() is documented as:

       creat()   is   equivalent   to   open()    with    flags    equal    
to
       O_CREAT|O_WRONLY|O_TRUNC.


There could be reasons that you would want to pass, say, O_CREAT|O_RDWR|
O_APPEND and omit O_TRUNC.

There are also reasons that you might want to pass, say, O_WRONLY|O_APPEND 
with no O_CREAT.  The fact that openFile implies O_CREAT sometimes is a 
serious misfeature IMHO.  That means bug.

-- John