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=-1.9 required=5.0 tests=BAYES_00 autolearn=ham
	autolearn_force=no version=3.4.4
X-Google-Thread: 103376,ae395e5c11de7bc9
X-Google-NewGroupId: yes
X-Google-Attributes: gida07f3367d7,domainid0,public,usenet
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news2.google.com!postnews.google.com!k6g2000prg.googlegroups.com!not-for-mail
From: Jerry <lanceboyle@qwest.net>
Newsgroups: comp.lang.ada
Subject: Re: segfault with large-ish array with GNAT
Date: Wed, 17 Mar 2010 23:45:25 -0700 (PDT)
Organization: http://groups.google.com
Message-ID: <ac4bed10-f655-4fa5-8891-2967ba4388a0@k6g2000prg.googlegroups.com>
References: 
 <642ddf8b-1d45-4f74-83ad-2c755040ca33@k24g2000pro.googlegroups.com>
	<cf178987-c893-4e93-83b7-c86b6aeeac48@q15g2000yqj.googlegroups.com>
	<4ba13454$0$6720$9b4e6d93@newsspool2.arcor-online.net>
NNTP-Posting-Host: 75.172.190.146
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
X-Trace: posting.google.com 1268894725 9592 127.0.0.1 (18 Mar 2010 06:45:25
 GMT)
X-Complaints-To: groups-abuse@google.com
NNTP-Posting-Date: Thu, 18 Mar 2010 06:45:25 +0000 (UTC)
Complaints-To: groups-abuse@google.com
Injection-Info: k6g2000prg.googlegroups.com; posting-host=75.172.190.146;
	posting-account=x5rpZwoAAABMN2XPwcebPWPkebpwQNJG
User-Agent: G2/1.0
X-HTTP-UserAgent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_5_8; en-US)
	AppleWebKit/528.16+(KHTML, like Gecko,
 Safari/528.16) OmniWeb/v622.8.0,gzip(gfe),gzip(gfe)
Xref: g2news2.google.com comp.lang.ada:10613
Date: 2010-03-17T23:45:25-07:00
List-Id: <comp.lang.ada>

Thanks for the helpful comments.

First,
  ulimit -s unlimited
does not work on OS X:
  -bash: ulimit: stack size: cannot modify limit: Operation not
permitted
but I understand that it works on Linux. And possibly the reason is
the difference in the way that Linux and OS X treat stack and heap
memory. (Don't be confused and think I know what I'm talking about but
I read that somewhere.)

ulimit allows querying the hard limit of stack space
  ulimit -Hs
which on OS X reports 65532 = 2^16 -4 kilobytes, about 67 MB. The user
via ulimit can set the stack up to that size but not higher:
  ulimit -s 65532
The default soft limit on OS X is 8192 kB, found by
  ulimit -s

So here's me being naive: I would have thought that Ada (or GNAT
specifically) would be smart enough to allocate memory for large
objects such as my long array in a transparent way so that I don't
have to worry about it, thus (in the Ada spirit) making it harder to
screw up. (Like not having to worry about whether arguments to
subprograms are passed by value or by reference--it just happens.)

But it seems that I will have to allocate memory for large objects
using pointers (and thus take the memory from the heap). Is that
right?

In this context, is there any advantage to declaring the large object
inside a declare block? Would that force the memory to be allocated
from the heap?

Jerry