From mboxrd@z Thu Jan  1 00:00:00 1970
Received: (from weis@localhost) by pauillac.inria.fr (8.7.6/8.7.3) id JAA21388 for caml-redistribution; Thu, 3 Jul 1997 09:43:58 +0200 (MET DST)
Received: from nez-perce.inria.fr (nez-perce.inria.fr [192.93.2.78]) by pauillac.inria.fr (8.7.6/8.7.3) with ESMTP id UAA18134 for <caml-list@pauillac.inria.fr>; Wed, 2 Jul 1997 20:44:16 +0200 (MET DST)
Received: from dwarin.oit.umass.edu (freya.cs.umass.edu [128.119.40.195]) by nez-perce.inria.fr (8.8.5/8.7.3) with ESMTP id UAA12615 for <caml-list@inria.fr>; Wed, 2 Jul 1997 20:44:09 +0200 (MET DST)
Received: (from ajenkins@localhost)
	by dwarin.oit.umass.edu (8.8.5/8.8.5) id OAA00394;
	Wed, 2 Jul 1997 14:43:10 -0400
Date: Wed, 2 Jul 1997 14:43:10 -0400
Message-Id: <199707021843.OAA00394@dwarin.oit.umass.edu>
From: "Adam P. Jenkins" <ajenkins@cs.umass.edu>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
To: caml-list@inria.fr
Subject: print and output
In-Reply-To: <v01530501afde7af99a9d@[129.88.38.40]>
References: <v01530501afde7af99a9d@[129.88.38.40]>
X-Mailer: VM 6.31 under Emacs 19.34.1
Sender: weis

Michel Levy writes:
 > Bonjour,
 > 
 > Quand j'ecris (en Ocaml) le "programme" suivant :
 >         print_string ">>"; read_int ();;
 > l'impression a lieu apres la lecture, ce qui me surprend, car il est dit
 > val read_int : unit -> int
 >         Flush standart output then ...
 > 
 > Quand j'ecris le "programme" suivant :
 >         output_string ">>"; read_int ();;
 > l'impression a lieu avant la lecture, ce qui est heureux.
 > 
 > Pourquoi cette diffence, car je pensais que :
 >         print_string = output_string stdout
 > 
 > Hi
 > 
 > When I write (in OCAML) the following program :
 >         print_string ">>"; read_int ();;
 > the reading takes place before the printing, what surprises me.
 > 
 > On the contrary, when I write :
 >         output_string ">>"; read_int ();;
 > the printing takes place before the reading, what is better.
 > 
 > Why this difference, whereas I thought that :
 >         print_string = output_string stdout
 > 
 > 
 > Michel Levy
 > D106 - Laboratoire LSR
 > B.P.72 - 38402 SAINT MARTIN D'HERES CEDEX - France
 > Tel : 0476827246
 > e.mail : Michel.Levy@imag.fr
 > 
 > 
 > 
 > 


That is kind of strange, since print_string is implemented with
output_string.  Maybe it just had to do with the order in which you
executed the commands, i.e. when the stdout buffer became full.

> cd /usr/local/lib/ocaml
> grep print_string pervasives.ml
let print_string s = output_string stdout s

To make the printing happen first in either case, you can add 
"flush stdout;".

	print_string ">>"; flush stdout; read_int ();;

Adam