From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID
	autolearn=no autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,ed86965848f8610b
X-Google-Attributes: gid103376,public
From: eachus@spectre.mitre.org (Robert I. Eachus)
Subject: Re: Reading environment variables in ADA?
Date: 1998/10/06
Message-ID: <EACHUS.98Oct6194412@spectre.mitre.org>#1/1
X-Deja-AN: 398450667
References: <6tdl75$qs6$2@nyheter.chalmers.se>
 <slrn702qlt.f3k.gisle@krake.ii.uib.no> <m34stiyb9n.fsf@mheaney.ni.net>
 <6vdgvv$2h3$1@nnrp1.dejanews.com>
Organization: The Mitre Corp., Bedford, MA.
Newsgroups: comp.lang.ada
Date: 1998-10-06T00:00:00+00:00
List-Id: <comp.lang.ada>

In article <6vdgvv$2h3$1@nnrp1.dejanews.com> dewarr@my-dejanews.com writes:

 > Note that if you declare a *constant* aliased string, then a good compiler
 > should not even allocate stack space, but instead allocate the constant
 > statically. This is what GNAT does, and I believe that at least some other
 > Ada compilers do this same optimization.

   Sorry, I have to recommend against this.  It is a constant to YOU,
but when it is passed to the C code, it is not.  I have found bugs in
both X windows and Solaris where the string is not actually changed,
but it is written to!  So if you pass a pointer to a string in the
code, you get a fault when the write occurs.  (Actually I suspect that
the terminating nul is rewritten.)

   (Don't ask me how these bugs occured, or why, and yes AFAIK, the
ones I have found have been fixed.  But it leads me to believe that
there are others.)
--

					Robert I. Eachus

with Standard_Disclaimer;
use  Standard_Disclaimer;
function Message (Text: in Clever_Ideas) return Better_Ideas is...