Re: [Caml-list] Destructive use of file descriptors

[Goswin von Brederlow <goswin-v-b@web.de>]

On Thu, Aug 06, 2015 at 07:50:38PM +0000, Malcolm Matalka wrote:
> Nicolas Ojeda Bar <n.oje.bar@gmail.com> writes:
> 
> > Hi,
> >
> > No magic needed in OCaml:
> >
> >   let with_open path f =
> >     let oc = open_out path in
> >     match f oc with
> >     | x -> close_out_noerr oc; x
> >     | exception e -> close_out_noerr oc; raise e
> >
> > and then use it as
> >
> >   with_open "foo" (fun oc -> output_string oc str)
> >
> > Cheers
> >
> > Nicolas
> >
> 
> The weakness with this (which I'm not sure if Python offers protection)
> is returning something that references the file created.  It can lead to
> some confusing error messages.

Yeah. I was thinking that that might be avoided. Something on the line
of putting the file descriptor into a local module so ocaml would
complain about it escaping its scope or something.

At least unlike the other suggestion this one closes the FD on exception.

MfG
	Goswin