From mboxrd@z Thu Jan  1 00:00:00 1970
Received: (from majordomo@localhost) by pauillac.inria.fr (8.7.6/8.7.3) id PAA04272; Tue, 16 Apr 2002 15:22:34 +0200 (MET DST)
X-Authentication-Warning: pauillac.inria.fr: majordomo set sender to owner-caml-list@pauillac.inria.fr using -f
Received: from concorde.inria.fr (concorde.inria.fr [192.93.2.39]) by pauillac.inria.fr (8.7.6/8.7.3) with ESMTP id PAA11102 for <caml-list@pauillac.inria.fr>; Tue, 16 Apr 2002 15:22:33 +0200 (MET DST)
X-SPAM-Warning: Sending machine is listed in blackholes.five-ten-sg.com
Received: from mel-rto7.wanadoo.fr (smtp-out-7.wanadoo.fr [193.252.19.26])
	by concorde.inria.fr (8.11.1/8.11.1) with ESMTP id g3GDMXb22461
	for <caml-list@inria.fr>; Tue, 16 Apr 2002 15:22:33 +0200 (MET DST)
Received: from mel-rta7.wanadoo.fr (193.252.19.61) by mel-rto7.wanadoo.fr; 16 Apr 2002 15:22:33 +0200
Received: from debian (80.8.76.40) by mel-rta7.wanadoo.fr (6.5.007)
        id 3CBAA820000616C4 for caml-list@inria.fr; Tue, 16 Apr 2002 15:22:33 +0200
Received: from moi by debian with local (Exim 3.35 #1 (Debian))
	id 16xSus-00019Z-00
	for <caml-list@inria.fr>; Tue, 16 Apr 2002 15:22:38 +0200
To: caml-list@inria.fr
Subject: Re: [Caml-list] Catching errors (Unix-Module)
References: <Pine.LNX.3.95.1020416150158.240A-100000@first.in-berlin.de>
From: Remi VANICAT <vanicat@labri.u-bordeaux.fr>
Date: 16 Apr 2002 15:22:38 +0200
In-Reply-To: <Pine.LNX.3.95.1020416150158.240A-100000@first.in-berlin.de>
Message-ID: <87hembbwwx.dlv@wanadoo.fr>
User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.2
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-15
Content-Transfer-Encoding: 8bit
Sender: owner-caml-list@pauillac.inria.fr
Precedence: bulk

Oliver Bandel <oliver@first.in-berlin.de> writes:

> Hello,
> 
> On Mon, 15 Apr 2002, Shawn Wagner wrote:
> 
> > try
> >  Unix.stat "/foo/bar"
> > with
> > | Unix.Unix_error (code, func, file) ->
> >   Printf.fprintf stderr "Couldn't %s '%s': %s!\n"
> >     func file (Unix.error_message code)
> 
> 
> OK, let's try it:
> ============================================
> oliver@first:/home/oliver > unix-top
>         Objective Caml version 3.01
> 
> # 
> try
>  Unix.stat "/foo/bar"
> with
> | Unix.Unix_error (code, func, file) ->
>   Printf.fprintf stderr "Couldn't %s '%s': %s!\n"
>     func file (Unix.error_message code)
> 
>                 ;;
> Characters 74-161:
> This expression has type unit but is here used with type Unix.stats

Your expression have a type, an which ever case happen, it must return
a value of the same type (here Unix.stats), then Printf.fprintf
doesn't return something of type Unix.stats, an so this code doesn't
work.


Something like :
try
  Some (Unix.stat "/foo/bar")
with
 | Unix.Unix_error (code, func, file) ->
   Printf.fprintf stderr "Couldn't %s '%s': %s!\n"
     func file (Unix.error_message code);
   None

will work, as 
 
try
  Unix.stat "/foo/bar"
with
 | Unix.Unix_error (code, func, file) as exn ->
   Printf.fprintf stderr "Couldn't %s '%s': %s!\n"
     func file (Unix.error_message code)
   raise exn

(but in the latter case, the exception is reraised after the message
have been printed, it may not be what you want).



-- 
Rémi Vanicat
vanicat@labri.u-bordeaux.fr
http://dept-info.labri.u-bordeaux.fr/~vanicat
-------------------
To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr
Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/
Beginner's list: http://groups.yahoo.com/group/ocaml_beginners