From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from konig.elte.hu (konig.elte.hu [157.181.6.22]) by euclid.skiles.gatech.edu (8.7.3/8.7.3) with SMTP id OAA10628 for <zsh-workers@math.gatech.edu>; Tue, 12 Mar 1996 14:04:14 -0500 (EST)
Received: (from hzoli@localhost) by bolyai.cs.elte.hu (8.6.12/8.6.12) id UAA10007 for zsh-workers@math.gatech.edu; Tue, 12 Mar 1996 20:03:50 +0100
From: Zoltan Hidvegi <hzoli@cs.elte.hu>
Message-Id: <199603121903.UAA10007@bolyai.cs.elte.hu>
Subject: Buffered stderr on Linux
To: zsh-workers@math.gatech.edu (zsh-workers)
Date: Tue, 12 Mar 1996 20:03:49 +0100 (MET)
Organization: Dept. of Comp. Sci., Eotvos University, Budapest, Hungary
Phone: (36 1)2669833 ext: 2667, home phone: (36 1) 2752368
X-Mailer: ELM [version 2.4 PL25 ME8b+]
Mime-Version: 1.0
Content-Type: application/pgp; format=text; x-action=sign
Content-Transfer-Encoding: 7bit

-----BEGIN PGP SIGNED MESSAGE-----

setvbuf(stderr, NULL, _IOFBF, 0) should set stderr to be fully buffered.
Unfortunately it does not work on Linux.  It works for stdout but not for
stderr.  But there is no problem if an explicit buffer is given.  The patch
below fixes that problem.  I seems that this problem is Linux specific (and
maybe libc-5.2.18 - 5.3.5 specific) but it can be used unconditionally since
it does not requires more memory than the NULL pointer solituion since stdio
allocates a buffer anyway if there is none given.  Now I wander why is it
necessary to use malloc to allocate these buffers.  Is there anything against
using static char[BUFSIZ] buffers?

Zoltan


 *** Src/init.c	1996/03/05 01:44:31	1.13
 --- Src/init.c	1996/03/11 01:13:13
 ***************
 *** 346,354 ****
       argzero = ztrdup(argzero);
   }
   
 - #ifndef _IOFBF
   static char *outbuf, *errbuf;
 - #endif
   
   /**/
   void
 --- 346,352 ----
 ***************
 *** 360,375 ****
       int i;
   #endif
   
 - /* stdout, stderr fully buffered */
 - #ifdef _IOFBF
 -     setvbuf(stdout, NULL, _IOFBF, 0);
 -     setvbuf(stderr, NULL, _IOFBF, 0);
 - #else
       if (!outbuf)
   	outbuf = (char *) malloc(BUFSIZ);
       if (!errbuf)
   	errbuf = (char *) malloc(BUFSIZ);
   
       setbuffer(stdout, outbuf, BUFSIZ);
       setbuffer(stderr, errbuf, BUFSIZ);
   #endif
 --- 358,373 ----
       int i;
   #endif
   
       if (!outbuf)
   	outbuf = (char *) malloc(BUFSIZ);
       if (!errbuf)
   	errbuf = (char *) malloc(BUFSIZ);
   
 + /* stdout, stderr fully buffered */
 + #ifdef _IOFBF
 +     setvbuf(stdout, outbuf, _IOFBF, BUFSIZ);
 +     setvbuf(stderr, errbuf, _IOFBF, BUFSIZ);
 + #else
       setbuffer(stdout, outbuf, BUFSIZ);
       setbuffer(stderr, errbuf, BUFSIZ);
   #endif

-----BEGIN PGP SIGNATURE-----
Version: 2.6.3i
Charset: noconv

iQCVAwUBMUXKkwupSCiLN749AQGerAP9Hd/jakBNjyc/GO64gL3raF2aAoqNc0ZL
HbIeZMbF6E8fXgRpwuwfCfrf3/CePDLlLGM4f20d+M9cI6NfI+XgqEScEhzhyebR
PJPgbKfv6fZdOLDDnI2dtXEIR1HjJczIZRFWb1kL9q69KzdyRChN/36oFEagbJzT
Mt6UDNEokmw=
=MDY2
-----END PGP SIGNATURE-----