How to get the file descriptor of a handle?

[Jeremy Shaw]

Hello,

In GHC 6.12 there is no guarantee that a Handle is backed up by a file  
descriptor. That said,  check out the handleToFd defined on line 141  
here:

http://patch-tag.com/r/mae/sendfile/snapshot/current/content/pretty/src/Network/Socket/SendFile/Internal.hs

A better type might be:

handleToFd :: Handle -> IO (Maybe Fd)

instead of raising an exception. Having a Handle not backed by a Fd is  
not really an 'exceptional' condition after all.

- jeremy


On Feb 13, 2010, at 6:23 AM, Volker Wysk wrote:

> Hello
>
> I'd like to know how you get the file descriptor, which is  
> incapsulated in a handle. The libraries GHC.IO.Handle/ 
> GHC.IO.Handle.FD only provide for the other direction.
>
> The function haFD, which I've used before I've updated to the  
> current version of GHC (6.12), appears to be in use two times in the  
> libraries. But there isn't a definition anywhere.
>
>
> Any help would be appreciated.
>
> Cheers,
> Volker
>
>
> -- 
> Volker Wysk <pf3 at volker-wysk.de>
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