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Groups > comp.lang.c > #58782

Re: local arrays and stack

From Keith Thompson <kst-u@mib.org>
Newsgroups comp.lang.c
Subject Re: local arrays and stack
Date 2015-03-23 12:48 -0700
Organization None to speak of
Message-ID <877fu7trzy.fsf@kst-u.example.com> (permalink)
References (4 earlier) <87k2y7u48c.fsf@kst-u.example.com> <705a5674-dbc9-460a-a72c-50bf1946be01@googlegroups.com> <c80c4036-d4a7-4a3d-9821-393b3ec9544c@googlegroups.com> <87bnjjty2r.fsf@kst-u.example.com> <56cd397c-bac6-4eac-ab5a-5548a9473140@googlegroups.com>

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Xcott Craver <xcottcraver@gmail.com> writes:
> On Monday, March 23, 2015 at 1:37:23 PM UTC-4, Keith Thompson wrote:
>> Xcott Craver <@> writes:
>> > I can declare a 160MB array and see it on the stack.  It's just a matter
>> > of subtracting the relevant offset from the stack pointer.
>> 
>> Using what implementation?
>
> 64-bit OSX:
>
> #define LEN 40000000
> int main( void ) {
>         int array [LEN];  ....
>
> (lldb) disas --name main
> a.out`main at tester.c:12:
> a.out[0x100000ec0]:  pushq  %rbp
> a.out[0x100000ec1]:  movq   %rsp, %rbp
> a.out[0x100000ec4]:  subq   $0x9896820, %rsp  <---- 160000032 bytes
>
> The ulimit command tells me that I apparently have an 8192K soft limit, and a
> 65532K hard limit on the stack.  However, I can declare gigabyte-sized arrays,
> and dissassembly just shows the function subtracting insane amounts from the
> stack pointer.

I tried something similar on my system (Linux Mint, x86_64).  When I
just declared the array, the program compiled and ran without error.
When I assigned a value to an element near the end of the array, it died
with a segmentation fault.

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"

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local arrays and stack fir <profesor.fir@gmail.com> - 2015-03-22 01:51 -0700
  local arrays and stack asetofsymbols@gmail.com - 2015-03-22 02:23 -0700
  Re: local arrays and stack Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-03-22 13:22 -0700
    Re: local arrays and stack fir <profesor.fir@gmail.com> - 2015-03-23 01:55 -0700
  Re: local arrays and stack Xcott Craver <xcottcraver@gmail.com> - 2015-03-22 15:07 -0700
    Re: local arrays and stack fir <profesor.fir@gmail.com> - 2015-03-23 01:50 -0700
      Re: local arrays and stack Robert Wessel <robertwessel2@yahoo.com> - 2015-03-23 04:26 -0500
        Re: local arrays and stack fir <profesor.fir@gmail.com> - 2015-03-23 06:53 -0700
        Re: local arrays and stack Xcott Craver <xcottcraver@gmail.com> - 2015-03-23 07:29 -0700
          Re: local arrays and stack fir <profesor.fir@gmail.com> - 2015-03-23 08:34 -0700
          Re: local arrays and stack Robert Wessel <robertwessel2@yahoo.com> - 2015-03-23 19:57 -0500
          Re: local arrays and stack fir <profesor.fir@gmail.com> - 2015-03-24 04:01 -0700
            Re: local arrays and stack fir <profesor.fir@gmail.com> - 2015-03-24 04:37 -0700
            Re: local arrays and stack David Brown <david.brown@hesbynett.no> - 2015-03-24 13:04 +0100
              Re: local arrays and stack glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-03-24 17:29 +0000
                Re: local arrays and stack David Brown <david.brown@hesbynett.no> - 2015-03-24 20:01 +0100
        Re: local arrays and stack Keith Thompson <kst-u@mib.org> - 2015-03-23 08:24 -0700
          Re: local arrays and stack fir <profesor.fir@gmail.com> - 2015-03-23 08:42 -0700
            Re: local arrays and stack Bartc <bc@freeuk.com> - 2015-03-23 16:07 +0000
              Re: local arrays and stack fir <profesor.fir@gmail.com> - 2015-03-23 09:15 -0700
              Re: local arrays and stack Keith Thompson <kst-u@mib.org> - 2015-03-23 09:16 -0700
                Re: local arrays and stack Bartc <bc@freeuk.com> - 2015-03-23 16:34 +0000
                Re: local arrays and stack Xcott Craver <xcottcraver@gmail.com> - 2015-03-23 10:12 -0700
                Re: local arrays and stack Bartc <bc@freeuk.com> - 2015-03-23 17:44 +0000
                Re: local arrays and stack fir <profesor.fir@gmail.com> - 2015-03-23 11:47 -0700
                Re: local arrays and stack Xcott Craver <xcottcraver@gmail.com> - 2015-03-23 12:06 -0700
                Re: local arrays and stack Bartc <bc@freeuk.com> - 2015-03-23 20:25 +0000
                Re: local arrays and stack Xcott Craver <xcottcraver@gmail.com> - 2015-03-23 14:10 -0700
                Re: local arrays and stack Bartc <bc@freeuk.com> - 2015-03-23 22:22 +0000
                Re: local arrays and stack fir <profesor.fir@gmail.com> - 2015-03-23 23:57 -0700
                Re: local arrays and stack David Brown <david.brown@hesbynett.no> - 2015-03-24 10:28 +0100
                Re: local arrays and stack Bartc <bc@freeuk.com> - 2015-03-24 10:44 +0000
                Re: local arrays and stack Martin Shobe <martin.shobe@yahoo.com> - 2015-03-24 06:38 -0500
                Re: local arrays and stack Martin Shobe <martin.shobe@yahoo.com> - 2015-03-24 09:57 -0500
                Re: local arrays and stack David Brown <david.brown@hesbynett.no> - 2015-03-24 13:22 +0100
                Re: local arrays and stack Bartc <bc@freeuk.com> - 2015-03-25 16:07 +0000
                Re: local arrays and stack David Brown <david.brown@hesbynett.no> - 2015-03-25 17:42 +0100
                Re: local arrays and stack Bartc <bc@freeuk.com> - 2015-03-25 19:06 +0000
                Re: local arrays and stack fir <profesor.fir@gmail.com> - 2015-03-25 12:26 -0700
                Re: local arrays and stack fir <profesor.fir@gmail.com> - 2015-03-25 13:20 -0700
                Re: local arrays and stack Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-03-25 12:28 -0700
                Re: local arrays and stack David Brown <david.brown@hesbynett.no> - 2015-03-25 21:45 +0100
                Re: local arrays and stack Keith Thompson <kst-u@mib.org> - 2015-03-25 12:50 -0700
                Re: local arrays and stack Bartc <bc@freeuk.com> - 2015-03-25 22:33 +0000
                Re: local arrays and stack David Brown <david.brown@hesbynett.no> - 2015-03-25 23:57 +0100
                Re: local arrays and stack David Brown <david.brown@hesbynett.no> - 2015-03-25 21:42 +0100
                Re: local arrays and stack fir <profesor.fir@gmail.com> - 2015-03-25 09:55 -0700
                Re: local arrays and stack Keith Thompson <kst-u@mib.org> - 2015-03-25 12:36 -0700
                Re: local arrays and stack fir <profesor.fir@gmail.com> - 2015-03-25 13:04 -0700
                Re: local arrays and stack David Brown <david.brown@hesbynett.no> - 2015-03-25 21:52 +0100
                Re: local arrays and stack Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-03-25 15:18 -0700
                Re: local arrays and stack David Brown <david.brown@hesbynett.no> - 2015-03-26 00:02 +0100
                Re: local arrays and stack Melzzzzz <mel@zzzzz.com> - 2015-03-26 00:47 +0100
                Re: local arrays and stack Mel <mel@zzzzz.com> - 2015-03-24 14:58 +0100
                Re: local arrays and stack Xcott Craver <xcottcraver@gmail.com> - 2015-03-24 06:58 -0700
                Re: local arrays and stack Keith Thompson <kst-u@mib.org> - 2015-03-23 14:34 -0700
                Re: local arrays and stack David Brown <david.brown@hesbynett.no> - 2015-03-24 10:16 +0100
                Re: local arrays and stack David Brown <david.brown@hesbynett.no> - 2015-03-24 09:55 +0100
                Re: local arrays and stack Noob <root@127.0.0.1> - 2015-03-24 10:23 +0100
                Re: local arrays and stack Tim Rentsch <txr@alumni.caltech.edu> - 2015-03-24 12:18 -0700
                Re: local arrays and stack Keith Thompson <kst-u@mib.org> - 2015-03-24 13:42 -0700
                Re: local arrays and stack Tim Rentsch <txr@alumni.caltech.edu> - 2015-03-25 08:47 -0700
            Re: local arrays and stack Xcott Craver <xcottcraver@gmail.com> - 2015-03-23 09:32 -0700
              Re: local arrays and stack fir <profesor.fir@gmail.com> - 2015-03-23 09:57 -0700
              Re: local arrays and stack Keith Thompson <kst-u@mib.org> - 2015-03-23 10:37 -0700
                Re: local arrays and stack Xcott Craver <xcottcraver@gmail.com> - 2015-03-23 10:49 -0700
                Re: local arrays and stack Keith Thompson <kst-u@mib.org> - 2015-03-23 12:48 -0700
                Re: local arrays and stack jt@toerring.de (Jens Thoms Toerring) - 2015-03-23 22:29 +0000
                Re: local arrays and stack James Kuyper <jameskuyper@verizon.net> - 2015-03-23 19:03 -0400
                Re: local arrays and stack jt@toerring.de (Jens Thoms Toerring) - 2015-03-23 23:36 +0000
                Re: local arrays and stack fir <profesor.fir@gmail.com> - 2015-03-24 02:17 -0700
                Re: local arrays and stack Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-03-23 11:56 -0700
          Re: local arrays and stack Robert Wessel <robertwessel2@yahoo.com> - 2015-03-23 20:00 -0500
            Re: local arrays and stack David Brown <david.brown@hesbynett.no> - 2015-03-24 10:39 +0100

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