Re: standards/47119: putc_unlocked(3) is found even with -std=c89

[christos%zoulas.com@localhost (Christos Zoulas)]

The following reply was made to PR standards/47119; it has been noted by GNATS.

From: christos%zoulas.com@localhost (Christos Zoulas)
To: gnats-bugs%NetBSD.org@localhost, standards-manager%netbsd.org@localhost, 
        gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost, 
sdaoden%gmail.com@localhost
Cc: 
Subject: Re: standards/47119: putc_unlocked(3) is found even with -std=c89
Date: Wed, 24 Oct 2012 10:24:58 -0400

 On Oct 24,  2:10pm, sdaoden%gmail.com@localhost (Steffen "Daode" Nurpmeso) 
wrote:
 -- Subject: Re: standards/47119: putc_unlocked(3) is found even with -std=c89
 
 | The following reply was made to PR standards/47119; it has been noted by 
GNATS.
 | 
 | From: Steffen "Daode" Nurpmeso <sdaoden%gmail.com@localhost>
 | To: Martin Husemann <martin%duskware.de@localhost>
 | Cc: gnats-bugs%NetBSD.org@localhost
 | Subject: Re: standards/47119: putc_unlocked(3) is found even with -std=c89
 | Date: Wed, 24 Oct 2012 16:05:07 +0200
 | 
 |  Martin Husemann <martin%duskware.de@localhost> wrote:
 |  
 |   |On Wed, Oct 24, 2012 at 03:11:03PM +0200, Steffen Daode Nurpmeso wrote:
 |   |> Because it is not part of C89/C99?
 |   |
 |   |You are misunderstanding the compiler option - it has no influence on the
 |   |symbols visible in libraries nor system headers (at least in general).
 |   |There are a few defines you can add via -D to make the headers pollute 
less
 |  
 |  Hmm.  I think you're right.
 |  Well i'm not really working with those headers, and i still see
 |  a '#define _GNU_SOURCE' on top of the one that's really important
 |  for me.
 |  
 |   |namespace, but since this is a posix blessed function, it is better
 |   |to avoid a name clash in application code.
 |   |Martin
 |  
 |  Yes, a lot of conditions and a lot of what standards produce most
 |  of the time, so thanks for all those work on standard compliance.
 |  
 |  Nonetheless - the bug is triggered only with -std=c89, and only on
 |  NetBSD 6.0.  And in the meanwhile i've found it.
 |  In fact it has nothing to do with putc_unlocked() (i was so clumsy
 |  that i even tried to compile with -pthread and -D_REENTRANT, and
 |  it was still expanded to __sputc() or so - amazing!), but it is in
 |  fact alloca(3) that returns an invalid buffer:
 |  
 |    %fwrite_td() calls ac_alloc for 29
 |    fwrite_td() calls memcpy (From: <XXXXXXXXXXX%YYYY.com@localhost>
 |    )29
 |    fwrite_td() before delctrl (^])29
 |    fwrite_td() calls prefixwrite (^])29
 |    *29 (0xbfbf9254)()*^@^@^@^@^@^@^@^@XXXXXXXXXX%YYYY.com@localhost>
 |  
 |  From the alloca(3) manual i see nothing special to adhere to,
 |  i would not describe 29 bytes as a "large unbounded allocation".
 |  The CFLAGS are simply '-std=c89 -O2', so nothing special at all.
 |  I think this is worth another PR?
 
 You are probably missing some include header (stdlib.h) and there
 is no prototype for alloca()? Post the code...
 
 christos