Re: VLAs use less stack

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From	jgk@panix.com (Joe keane)
Newsgroups	comp.std.c
Subject	Re: VLAs use less stack
Date	Sun, 2 Sep 2012 16:56:55 +0000 (UTC)
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In article <lnsjb2ucn5.fsf@nuthaus.mib.org>,
Keith Thompson  <kst-u@mib.org> wrote:
>How common is that in practice?  In the absence of VLAs, if you don't
>know in advance how big the buffer needs to be, isn't it more common to
>use malloc() (and possibly realloc())?

That is the only way to handle the general case.

fixed-size array: fails at some point (can check for this)
and variable-size array: fails at some point (can't check for this)

>Interesting idea.  But I wonder how often it's really worthwhile
>in practice.  In terms of code complexity, it offers no advantage
>over using malloc/free uconditionally; you still have to make sure
>you call free() if the buffer was allocated with malloc(), so you
>lose that advantage of VLAs.

It is useful.  It's simply profiling.  If you find too much time spent
in malloc and free, fix it somehow...  This is one way.

Thread

VLAs use less stack jacob navia <jacob@spamsink.net> - 2012-08-31 12:58 +0200
  Re: VLAs use less stack Marc <marc.glisse@gmail.com> - 2012-08-31 14:10 +0000
    Re: VLAs use less stack Marc <marc.glisse@gmail.com> - 2012-08-31 14:13 +0000
    Re: VLAs use less stack jacob navia <jacob@spamsink.net> - 2012-08-31 18:09 +0200
    Re: VLAs use less stack jacob navia <jacob@spamsink.net> - 2012-08-31 18:14 +0200
    Re: VLAs use less stack John Nagle <nagle@animats.com> - 2012-09-01 12:24 -0700
      Re: VLAs use less stack jacob navia <jacob@spamsink.net> - 2012-09-01 22:57 +0200
      Re: VLAs use less stack jacob navia <jacob@spamsink.net> - 2012-09-01 22:59 +0200
  Re: VLAs use less stack Keith Thompson <kst-u@mib.org> - 2012-08-31 11:42 -0700
    Re: VLAs use less stack Marc <marc.glisse@gmail.com> - 2012-09-01 10:18 +0000
      Re: VLAs use less stack Rui Maciel <rui.maciel@gmail.com> - 2012-09-01 19:18 +0100
        Re: VLAs use less stack Marc <marc.glisse@gmail.com> - 2012-09-01 19:19 +0000
        Re: VLAs use less stack jacob navia <jacob@spamsink.net> - 2012-09-01 23:01 +0200
      Re: VLAs use less stack Keith Thompson <kst-u@mib.org> - 2012-09-01 11:36 -0700
        Re: VLAs use less stack Marc <marc.glisse@gmail.com> - 2012-09-01 19:05 +0000
    Re: VLAs use less stack jgk@panix.com (Joe keane) - 2012-09-02 16:56 +0000
      Re: VLAs use less stack Keith Thompson <kst-u@mib.org> - 2012-09-02 14:22 -0700
        Re: VLAs use less stack jgk@panix.com (Joe keane) - 2012-09-04 00:39 +0000
          Re: VLAs use less stack Jens Gustedt <jens.gustedt@loria.fr> - 2012-09-04 10:28 +0200
            Re: VLAs use less stack John Nagle <nagle@animats.com> - 2012-09-04 11:31 -0700
          Re: VLAs use less stack jacob navia <jacob@spamsink.net> - 2012-09-04 17:02 +0200
      Re: VLAs use less stack jacob navia <jacob@spamsink.net> - 2012-09-02 23:28 +0200
      Re: VLAs use less stack Keith Thompson <kst-u@mib.org> - 2012-09-02 14:37 -0700
        Re: VLAs use less stack John Nagle <nagle@animats.com> - 2012-09-02 15:45 -0700
          Re: VLAs use less stack Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2012-09-04 00:03 +0200
  Re: VLAs use less stack jgk@panix.com (Joe keane) - 2012-09-01 16:09 +0000
    Re: VLAs use less stack Keith Thompson <kst-u@mib.org> - 2012-09-01 11:45 -0700
    Re: VLAs use less stack jacob navia <jacob@spamsink.net> - 2012-09-01 23:05 +0200

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