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Groups > comp.lang.c > #58988

Re: local arrays and stack

From Melzzzzz <mel@zzzzz.com>
Newsgroups comp.lang.c
Subject Re: local arrays and stack
Date 2015-03-26 00:47 +0100
Organization albasani.net
Message-ID <20150326004746.0d8489bc@maxa-pc> (permalink)
References (17 earlier) <merksa$ko5$1@dont-email.me> <meumeh$3pd$1@dont-email.me> <87twx8q37f.fsf@kst-u.example.com> <mev74f$gta$1@dont-email.me> <cfce1604-afba-4269-b9db-4907eb816201@googlegroups.com>

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On Wed, 25 Mar 2015 15:18:21 -0700 (PDT)
Malcolm McLean <malcolm.mclean5@btinternet.com> wrote:

> On Wednesday, March 25, 2015 at 8:52:26 PM UTC, David Brown wrote:
> >
> > Also note that for an unknown size N, allocating an "array[N]"
> > object on the heap is just as bad practice as allocating it on the
> > stack.  
> >
> You check the return from malloc(). If null, you can't do the 
> calculation.
> However a lot of people write (it's even been described as the clc-
> approved way)
> 
> EMPLOYEE *ptr = malloc(N * sizeof *ptr);
> 
> that of course will overflow for sufficiently large N, and may appear
> to succeed.
> 
> Some bad operating systems / C compilers allow user code to allocate 
> too much memory, causing problems elsewhere.

Problem are GC's, not compilers. They mmap too much RAM initially...
Other thing is forking. Without overcommit one couldn't run
Java or anything that maps initially large amount of RAM. 

 User processes shouldn't
> be allowed to grab resources that prevent housekeeping programs from
> functioning, whether that be mouse, keyboard, screen, disk, processor,
> memory or anything else.  

Problem is that user processes nowadays allocate too much
in front...

> 

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Thread

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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