Re: evaluate a generic swap function

From	Nelu <tandauioan@gmail.com>
Newsgroups	comp.lang.c
Subject	Re: evaluate a generic swap function
Date	2011-09-23 12:54 -0700
Organization	http://groups.google.com
Message-ID	<2158111.1838.1316807699210.JavaMail.geo-discussion-forums@yqjw35> (permalink)
References	(1 earlier) <slrnj7nobn.124n.usenet-nospam@guild.seebs.net> <11027611.3262.1316798819548.JavaMail.geo-discussion-forums@yqjc18> <0.cd4cbe9b01c698079f35.20110923183607BST.87y5xfw48o.fsf@bsb.me.uk> <2208063.1130.1316800191576.JavaMail.geo-discussion-forums@yqih9> <0.b6bffa64cc312244356e.20110923201821BST.87hb43vzib.fsf@bsb.me.uk>

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On Friday, September 23, 2011 3:18:20 PM UTC-4, Ben Bacarisse wrote:
> Nelu <tanda...@gmail.com> writes:
> 
> <snip>
> > Yes, but memory for the tmp variable in your example is
> > allocated/deallocated every time you enter/exit the block of code. The
> > static variable is allocated at the start of the program and
> > successive calls to the function will not need to allocate more
> > memory. Same with the thread local variables as long as you reuse the
> > same threads, no?
> 
> It is a rare program that has to worry about the allocation of an
> automatic array.  The CPU cost is often zero.  Since a swap that uses an
> auto buffer is entirely portable and is likely as efficient as one that
> uses non-portable thread local storage or possibly problematic static
> storage, it's the way I'd go every time.

That makes sense. In the DOS days the stack size was a limiting factor, I think. Is the size of the automatic array subject to implementation or are there minimal requirements imposed by the standard?

Thread

evaluate a generic swap function Stanley Rice <heconghui@gmail.com> - 2011-09-20 06:51 -0700
  Re: evaluate a generic swap function jacob navia <jacob@spamsink.net> - 2011-09-20 16:01 +0200
    Re: evaluate a generic swap function jt@toerring.de (Jens Thoms Toerring) - 2011-09-20 14:29 +0000
      Re: evaluate a generic swap function jacob navia <jacob@spamsink.net> - 2011-09-20 21:13 +0200
        Re: evaluate a generic swap function jt@toerring.de (Jens Thoms Toerring) - 2011-09-20 20:30 +0000
          Re: evaluate a generic swap function Keith Thompson <kst-u@mib.org> - 2011-09-20 17:05 -0700
            Re: evaluate a generic swap function gazelle@shell.xmission.com (Kenny McCormack) - 2011-09-21 15:45 +0000
              Re: evaluate a generic swap function Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-09-21 09:33 -0700
              Re: evaluate a generic swap function jacob navia <jacob@spamsink.net> - 2011-09-21 19:17 +0200
                Re: evaluate a generic swap function gazelle@shell.xmission.com (Kenny McCormack) - 2011-09-21 17:34 +0000
                Re: evaluate a generic swap function Jack Foot <foot@dev.null.invalid> - 2011-09-21 18:12 +0000
  Re: evaluate a generic swap function Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-09-20 07:33 -0700
    Re: evaluate a generic swap function ImpalerCore <jadill33@gmail.com> - 2011-09-20 08:26 -0700
      Re: evaluate a generic swap function pete <pfiland@mindspring.com> - 2011-09-20 23:10 -0400
  Re: evaluate a generic swap function "BartC" <bc@freeuk.com> - 2011-09-20 22:20 +0100
    Re: evaluate a generic swap function jacob navia <jacob@spamsink.net> - 2011-09-20 23:23 +0200
      Re: evaluate a generic swap function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-09-20 23:07 +0100
  Re: evaluate a generic swap function Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-09-20 21:15 -0400
    Re: evaluate a generic swap function Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-09-21 03:17 -0700
  Re: evaluate a generic swap function Gene <gene.ressler@gmail.com> - 2011-09-21 02:40 -0700
  Re: evaluate a generic swap function Seebs <usenet-nospam@seebs.net> - 2011-09-23 01:46 +0000
    Re: evaluate a generic swap function Nelu <tandauioan@gmail.com> - 2011-09-23 10:26 -0700
      Re: evaluate a generic swap function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-09-23 18:36 +0100
        Re: evaluate a generic swap function Nelu <tandauioan@gmail.com> - 2011-09-23 10:49 -0700
          Re: evaluate a generic swap function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-09-23 20:18 +0100
            Re: evaluate a generic swap function Nelu <tandauioan@gmail.com> - 2011-09-23 12:54 -0700
              Re: evaluate a generic swap function James Kuyper <jameskuyper@verizon.net> - 2011-09-23 16:43 -0400
                Re: evaluate a generic swap function Nelu <tandauioan@gmail.com> - 2011-09-23 13:49 -0700
                Re: evaluate a generic swap function James Kuyper <jameskuyper@verizon.net> - 2011-09-23 17:44 -0400
                Re: evaluate a generic swap function Nelu <tandauioan@gmail.com> - 2011-09-23 18:04 -0700
                Re: evaluate a generic swap function Tim Rentsch <txr@alumni.caltech.edu> - 2012-01-24 13:52 -0800
              Re: evaluate a generic swap function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-09-23 21:46 +0100
                Re: evaluate a generic swap function Nelu <tandauioan@gmail.com> - 2011-09-23 13:59 -0700
                Re: evaluate a generic swap function Seebs <usenet-nospam@seebs.net> - 2011-09-26 22:59 +0000
          Re: evaluate a generic swap function pete <pfiland@mindspring.com> - 2011-09-23 18:19 -0400
            Re: evaluate a generic swap function Nelu <tandauioan@gmail.com> - 2011-09-23 16:36 -0700

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