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Re: Dinamic array without malloc - Can be done?

From "Chris M. Thomasson" <invalid@invalid.invalid>
Newsgroups comp.lang.c
Subject Re: Dinamic array without malloc - Can be done?
Date 2017-01-16 11:25 -0800
Organization n/a
Message-ID <o5j6jp$7d9$1@dont-email.me> (permalink)
References (3 earlier) <n0kn7c1t8a7tbnjbt1ir4hikahmtakp7hp@4ax.com> <89d69ff5-913b-4d29-8342-356ab722d590@googlegroups.com> <0d0bd6eb-2cda-4ecc-9b64-5c99ef7a96e2@googlegroups.com> <o5i34g$3i0$1@dont-email.me> <o5iams$s6h$1@dont-email.me>

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On 1/16/2017 3:28 AM, BartC wrote:
> On 16/01/2017 09:19, David Brown wrote:
>> On 16/01/17 01:01, supercat@casperkitty.com wrote:
>
>>> Using fixed-sized arrays is almost certainly going to be faster if
>>> adequate stack space exists to handle the maximum sizes, and may
>>> well end up having a lower worst-case stack space requirement as
>>> well.  On some systems there may be good usage cases for VLAs, but
>>> the minimum size to make VLA usage really worthwhile on some systems
>>> may be larger than the size to make them blow up on others.
>>>
>>
>> That is simply nonsense.
>>
>> It is rare that Fir posts anything the makes sense, but in this thread
>> he actually did so - allocating a local array on the stack is basically
>> nothing more than an adjustment of the stack pointer.  It does not
>> matter significantly whether that adjustment is of a fixed size known at
>> compile time, or a value calculated at run-time.
>
> But the adjustment isn't done at entry to a function with all the other
> fixed-size objects (or not at all if a conventional stack frame is not
> used).
>
> It's done separately after executing some code (calculating the length
> of the array). If it's in a loop, it can mean deallocating the space,
> and then allocating a new offset, each time around.

Deallocating the "some" space and atomically realigning the pointers.

Wow, this reminds me of when I was programming servers in winnt using 
IOCP. Re/deallocating wrt going into dropping "slow/timedout 
connections" in panic mode wrt too many clients, (back then I could 
handle around 60,000 loaded and live (active) connections) on winnt.

Actually, this brings back a database like mutex based technique that 
can atomically lock multiple records/objects, at once, akin to lock 
based transactional memory IIRC, the deadlock avoiding locking pattern 
can be outfitted with rwlocks instead of mutex...


>
> Furthermore, on some implementations such as gcc on x86, it can mean
> calling a function (__chkstk_ms()) to check the allocation isn't so
> large that it exceeds the stack guard page. This is not needed if it
> knows the local array will not be a beyond a certain size (I think 4KB
> or less total stack allocation within a function).
>

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Dinamic array without malloc - Can be done? "Fernando D. Bozzo" <fdbozzo@gmail.com> - 2017-01-15 08:45 -0800
  Re: Dinamic array without malloc - Can be done? BartC <bc@freeuk.com> - 2017-01-15 16:53 +0000
    Re: Dinamic array without malloc - Can be done? fir <profesor.fir@gmail.com> - 2017-01-15 09:34 -0800
      Re: Dinamic array without malloc - Can be done? BartC <bc@freeuk.com> - 2017-01-17 21:09 +0000
        Re: Dinamic array without malloc - Can be done? fir <profesor.fir@gmail.com> - 2017-01-17 13:45 -0800
          Re: Dinamic array without malloc - Can be done? fir <profesor.fir@gmail.com> - 2017-01-17 14:09 -0800
          Re: Dinamic array without malloc - Can be done? BartC <bc@freeuk.com> - 2017-01-17 22:41 +0000
          Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-17 15:06 -0800
            Re: Dinamic array without malloc - Can be done? fir <profesor.fir@gmail.com> - 2017-01-17 16:49 -0800
            Re: Dinamic array without malloc - Can be done? Keith Thompson <kst-u@mib.org> - 2017-01-17 16:56 -0800
              Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-17 20:37 -0800
                Re: Dinamic array without malloc - Can be done? David Brown <david.brown@hesbynett.no> - 2017-01-18 09:38 +0100
                Re: Dinamic array without malloc - Can be done? Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-31 08:49 -0800
                Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-31 10:39 -0800
                Re: Dinamic array without malloc - Can be done? luser droog <luser.droog@gmail.com> - 2017-01-31 10:55 -0800
                Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-31 11:40 -0800
                Re: Dinamic array without malloc - Can be done? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2017-01-31 10:57 -0800
                Re: Dinamic array without malloc - Can be done? Tim Rentsch <txr@alumni.caltech.edu> - 2017-02-03 23:06 -0800
    Re: Dinamic array without malloc - Can be done? "Fernando D. Bozzo" <fdbozzo@gmail.com> - 2017-01-15 10:42 -0800
      Re: Dinamic array without malloc - Can be done? BartC <bc@freeuk.com> - 2017-01-15 20:15 +0000
        Re: Dinamic array without malloc - Can be done? Keith Thompson <kst-u@mib.org> - 2017-01-15 12:43 -0800
        Re: Dinamic array without malloc - Can be done? "Fernando D. Bozzo" <fdbozzo@gmail.com> - 2017-01-15 15:08 -0800
  Re: Dinamic array without malloc - Can be done? "James R. Kuyper" <jameskuyper@verizon.net> - 2017-01-15 12:25 -0500
    Re: Dinamic array without malloc - Can be done? "Fernando D. Bozzo" <fdbozzo@gmail.com> - 2017-01-15 10:46 -0800
      Re: Dinamic array without malloc - Can be done? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-15 20:13 +0000
        Re: Dinamic array without malloc - Can be done? "Fernando D. Bozzo" <fdbozzo@gmail.com> - 2017-01-15 15:06 -0800
    Re: Dinamic array without malloc - Can be done? Keith Thompson <kst-u@mib.org> - 2017-01-15 12:46 -0800
      Re: Dinamic array without malloc - Can be done? "James R. Kuyper" <jameskuyper@verizon.net> - 2017-01-15 16:10 -0500
      Re: Dinamic array without malloc - Can be done? Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-15 20:37 -0800
        Re: Dinamic array without malloc - Can be done? Keith Thompson <kst-u@mib.org> - 2017-01-15 21:02 -0800
          Re: Dinamic array without malloc - Can be done? Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-30 04:23 -0800
        Re: Dinamic array without malloc - Can be done? David Brown <david.brown@hesbynett.no> - 2017-01-16 09:05 +0100
          Re: Dinamic array without malloc - Can be done? Ian Collins <ian-news@hotmail.com> - 2017-01-16 21:16 +1300
            Re: Dinamic array without malloc - Can be done? David Brown <david.brown@hesbynett.no> - 2017-01-16 09:48 +0100
  Re: Dinamic array without malloc - Can be done? fir <profesor.fir@gmail.com> - 2017-01-15 09:29 -0800
    Re: Dinamic array without malloc - Can be done? fir <profesor.fir@gmail.com> - 2017-01-15 09:37 -0800
    Re: Dinamic array without malloc - Can be done? fir <profesor.fir@gmail.com> - 2017-01-15 09:56 -0800
      Re: Dinamic array without malloc - Can be done? fir <profesor.fir@gmail.com> - 2017-01-15 10:34 -0800
    Re: Dinamic array without malloc - Can be done? "Fernando D. Bozzo" <fdbozzo@gmail.com> - 2017-01-15 10:48 -0800
      Re: Dinamic array without malloc - Can be done? fir <profesor.fir@gmail.com> - 2017-01-15 11:10 -0800
      Re: Dinamic array without malloc - Can be done? Jean-Marc Bourguet <jm@bourguet.org> - 2017-01-15 20:22 +0100
        Re: Dinamic array without malloc - Can be done? Chad <cdalten@gmail.com> - 2017-01-15 11:50 -0800
        Re: Dinamic array without malloc - Can be done? "Fernando D. Bozzo" <fdbozzo@gmail.com> - 2017-01-15 15:12 -0800
  Re: Dinamic array without malloc - Can be done? Richard Heathfield <rjh@cpax.org.uk> - 2017-01-15 17:50 +0000
    Re: Dinamic array without malloc - Can be done? "Fernando D. Bozzo" <fdbozzo@gmail.com> - 2017-01-15 10:38 -0800
      Re: Dinamic array without malloc - Can be done? Richard Heathfield <rjh@cpax.org.uk> - 2017-01-15 19:34 +0000
        Re: Dinamic array without malloc - Can be done? Keith Thompson <kst-u@mib.org> - 2017-01-15 12:51 -0800
          Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-15 13:10 -0800
            Re: Dinamic array without malloc - Can be done? Keith Thompson <kst-u@mib.org> - 2017-01-15 16:23 -0800
              Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-15 18:08 -0800
            Re: Dinamic array without malloc - Can be done? David Brown <david.brown@hesbynett.no> - 2017-01-16 09:56 +0100
              Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-16 08:35 -0800
                Re: Dinamic array without malloc - Can be done? "Chris M. Thomasson" <invalid@invalid.invalid> - 2017-01-16 11:07 -0800
                Re: Dinamic array without malloc - Can be done? "Chris M. Thomasson" <invalid@invalid.invalid> - 2017-01-16 11:17 -0800
                Re: Dinamic array without malloc - Can be done? Robert Wessel <robertwessel2@yahoo.com> - 2017-01-16 15:21 -0600
                Re: Dinamic array without malloc - Can be done? "Chris M. Thomasson" <invalid@invalid.invalid> - 2017-01-31 22:22 -0800
                Re: Dinamic array without malloc - Can be done? David Brown <david.brown@hesbynett.no> - 2017-01-17 00:22 +0100
                Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-16 16:23 -0800
                Re: Dinamic array without malloc - Can be done? David Brown <david.brown@hesbynett.no> - 2017-01-17 02:04 +0100
                Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-16 17:27 -0800
                Re: Dinamic array without malloc - Can be done? David Brown <david.brown@hesbynett.no> - 2017-01-17 09:16 +0100
          Re: Dinamic array without malloc - Can be done? Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-15 20:32 -0800
          Re: Dinamic array without malloc - Can be done? David Brown <david.brown@hesbynett.no> - 2017-01-16 10:02 +0100
            Re: Dinamic array without malloc - Can be done? Keith Thompson <kst-u@mib.org> - 2017-01-16 09:22 -0800
              Re: Dinamic array without malloc - Can be done? David Brown <david.brown@hesbynett.no> - 2017-01-17 00:25 +0100
      Re: Dinamic array without malloc - Can be done? Barry Schwarz <schwarzb@dqel.com> - 2017-01-15 11:53 -0800
        Re: Dinamic array without malloc - Can be done? fir <profesor.fir@gmail.com> - 2017-01-15 12:22 -0800
        Re: Dinamic array without malloc - Can be done? "Fernando D. Bozzo" <fdbozzo@gmail.com> - 2017-01-15 15:32 -0800
          Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-15 16:01 -0800
            Re: Dinamic array without malloc - Can be done? David Brown <david.brown@hesbynett.no> - 2017-01-16 10:19 +0100
              Re: Dinamic array without malloc - Can be done? BartC <bc@freeuk.com> - 2017-01-16 11:28 +0000
                Re: Dinamic array without malloc - Can be done? David Brown <david.brown@hesbynett.no> - 2017-01-16 14:29 +0100
                Re: Dinamic array without malloc - Can be done? BartC <bc@freeuk.com> - 2017-01-16 15:41 +0000
                Re: Dinamic array without malloc - Can be done? David Brown <david.brown@hesbynett.no> - 2017-01-16 17:27 +0100
                Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-16 07:56 -0800
                Re: Dinamic array without malloc - Can be done? David Brown <david.brown@hesbynett.no> - 2017-01-16 17:31 +0100
                Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-16 08:48 -0800
                Re: Dinamic array without malloc - Can be done? David Brown <david.brown@hesbynett.no> - 2017-01-17 00:29 +0100
                Re: Dinamic array without malloc - Can be done? "Chris M. Thomasson" <invalid@invalid.invalid> - 2017-01-16 11:25 -0800
                Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-16 12:28 -0800
                Re: Dinamic array without malloc - Can be done? "Chris M. Thomasson" <invalid@invalid.invalid> - 2017-01-16 12:38 -0800
          Re: Dinamic array without malloc - Can be done? Keith Thompson <kst-u@mib.org> - 2017-01-15 16:57 -0800
            Re: Dinamic array without malloc - Can be done? "Fernando D. Bozzo" <fdbozzo@gmail.com> - 2017-01-16 00:37 -0800
              Re: Dinamic array without malloc - Can be done? David Brown <david.brown@hesbynett.no> - 2017-01-16 10:23 +0100
                Re: Dinamic array without malloc - Can be done? "Fernando D. Bozzo" <fdbozzo@gmail.com> - 2017-01-16 01:35 -0800
                Re: Dinamic array without malloc - Can be done? Keith Thompson <kst-u@mib.org> - 2017-01-16 09:15 -0800
          Re: Dinamic array without malloc - Can be done? BartC <bc@freeuk.com> - 2017-01-16 01:29 +0000
        Re: Dinamic array without malloc - Can be done? David Brown <david.brown@hesbynett.no> - 2017-01-16 10:08 +0100
          Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-16 08:08 -0800
            Re: Dinamic array without malloc - Can be done? David Brown <david.brown@hesbynett.no> - 2017-01-17 00:35 +0100
              Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-16 16:31 -0800
                Re: Dinamic array without malloc - Can be done? David Brown <david.brown@hesbynett.no> - 2017-01-17 09:27 +0100
                Re: Dinamic array without malloc - Can be done? BartC <bc@freeuk.com> - 2017-01-17 12:11 +0000
                Re: Dinamic array without malloc - Can be done? David Brown <david.brown@hesbynett.no> - 2017-01-17 14:23 +0100
                Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-17 05:38 -0800
                Re: Dinamic array without malloc - Can be done? BartC <bc@freeuk.com> - 2017-01-17 14:17 +0000
                Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-17 07:09 -0800
                Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-17 05:14 -0800
                Re: Dinamic array without malloc - Can be done? David Brown <david.brown@hesbynett.no> - 2017-01-17 14:40 +0100
                Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-17 06:41 -0800
                Re: Dinamic array without malloc - Can be done? David Brown <david.brown@hesbynett.no> - 2017-01-17 16:00 +0100
                Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-17 07:45 -0800
                Re: Dinamic array without malloc - Can be done? fir <profesor.fir@gmail.com> - 2017-01-17 08:18 -0800
                Re: Dinamic array without malloc - Can be done? fir <profesor.fir@gmail.com> - 2017-01-17 08:27 -0800
                Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-17 09:29 -0800
                Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-17 09:23 -0800
                Re: Dinamic array without malloc - Can be done? fir <profesor.fir@gmail.com> - 2017-01-17 10:35 -0800
                Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-17 12:41 -0800
                Re: Dinamic array without malloc - Can be done? fir <profesor.fir@gmail.com> - 2017-01-17 13:45 -0800
                Re: Dinamic array without malloc - Can be done? Robert Wessel <robertwessel2@yahoo.com> - 2017-01-17 21:00 -0600
      Re: Dinamic array without malloc - Can be done? fir <profesor.fir@gmail.com> - 2017-01-15 11:55 -0800
      Re: Dinamic array without malloc - Can be done? Siri Cruise <chine.bleu@yahoo.com> - 2017-01-15 14:59 -0800
    Re: Dinamic array without malloc - Can be done? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-15 20:04 +0000
      Re: Dinamic array without malloc - Can be done? David Brown <david.brown@hesbynett.no> - 2017-01-15 21:33 +0100
        Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-15 13:00 -0800
          Re: Dinamic array without malloc - Can be done? Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-15 20:27 -0800
        Re: Dinamic array without malloc - Can be done? "James R. Kuyper" <jameskuyper@verizon.net> - 2017-01-15 16:34 -0500
          Re: Dinamic array without malloc - Can be done? "James R. Kuyper" <jameskuyper@verizon.net> - 2017-01-15 16:43 -0500
            Re: Dinamic array without malloc - Can be done? Keith Thompson <kst-u@mib.org> - 2017-01-15 16:17 -0800
              Re: Dinamic array without malloc - Can be done? Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-15 20:22 -0800
                Re: Dinamic array without malloc - Can be done? Keith Thompson <kst-u@mib.org> - 2017-01-15 21:00 -0800
                Re: Dinamic array without malloc - Can be done? Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-30 05:01 -0800
                Re: Dinamic array without malloc - Can be done? Keith Thompson <kst-u@mib.org> - 2017-01-30 11:35 -0800
                Re: Dinamic array without malloc - Can be done? Tim Rentsch <txr@alumni.caltech.edu> - 2017-02-01 16:18 -0800
                Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-02-01 16:37 -0800
                Re: Dinamic array without malloc - Can be done? Robert Wessel <robertwessel2@yahoo.com> - 2017-02-01 23:21 -0600
                Re: Dinamic array without malloc - Can be done? Tim Rentsch <txr@alumni.caltech.edu> - 2017-02-02 00:27 -0800
                Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-02-02 10:58 -0800
                Re: Dinamic array without malloc - Can be done? Tim Rentsch <txr@alumni.caltech.edu> - 2017-02-03 22:51 -0800
  Re: Dinamic array without malloc - Can be done? "Chris M. Thomasson" <invalid@invalid.invalid> - 2017-01-15 15:41 -0800
    Re: Dinamic array without malloc - Can be done? "Fernando D. Bozzo" <fdbozzo@gmail.com> - 2017-01-15 15:44 -0800
      Re: Dinamic array without malloc - Can be done? "Chris M. Thomasson" <invalid@invalid.invalid> - 2017-01-15 16:17 -0800
  Re: Dinamic array without malloc - Can be done? Alla _ <modelling.data@gmail.com> - 2017-01-16 01:47 -0800
    Re: Dinamic array without malloc - Can be done? "Fernando D. Bozzo" <fdbozzo@gmail.com> - 2017-01-16 01:50 -0800
      Re: Dinamic array without malloc - Can be done? Alla _ <modelling.data@gmail.com> - 2017-01-16 02:38 -0800
        Re: Dinamic array without malloc - Can be done? "Fernando D. Bozzo" <fdbozzo@gmail.com> - 2017-01-16 03:15 -0800
          Re: Dinamic array without malloc - Can be done? Alla _ <modelling.data@gmail.com> - 2017-01-16 03:40 -0800
            Re: Dinamic array without malloc - Can be done? "Fernando D. Bozzo" <fdbozzo@gmail.com> - 2017-01-16 04:21 -0800
          Re: Dinamic array without malloc - Can be done? Alla _ <modelling.data@gmail.com> - 2017-01-16 04:29 -0800
            Re: Dinamic array without malloc - Can be done? "Fernando D. Bozzo" <fdbozzo@gmail.com> - 2017-01-16 04:36 -0800
    Re: Dinamic array without malloc - Can be done? Richard Heathfield <rjh@cpax.org.uk> - 2017-01-16 11:36 +0000
      Re: Dinamic array without malloc - Can be done? Alla _ <modelling.data@gmail.com> - 2017-01-16 03:44 -0800
      Re: Dinamic array without malloc - Can be done? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-16 15:34 +0000
        Re: Dinamic array without malloc - Can be done? Richard Heathfield <rjh@cpax.org.uk> - 2017-01-16 16:01 +0000
  Re: Dinamic array without malloc - Can be done? John Bode <jfbode1029@gmail.com> - 2017-01-17 10:14 -0800
    Re: Dinamic array without malloc - Can be done? James Kuyper <jameskuyper@verizon.net> - 2017-01-17 13:21 -0500
      Re: Dinamic array without malloc - Can be done? John Bode <jfbode1029@gmail.com> - 2017-01-17 11:43 -0800
        Re: Dinamic array without malloc - Can be done? James Kuyper <jameskuyper@verizon.net> - 2017-01-17 15:07 -0500
      Re: Dinamic array without malloc - Can be done? supercat@casperkitty.com - 2017-01-17 12:24 -0800
    Re: Dinamic array without malloc - Can be done? "Fernando D. Bozzo" <fdbozzo@gmail.com> - 2017-01-17 10:24 -0800
    Re: Dinamic array without malloc - Can be done? Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-30 05:21 -0800

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