Re: VC++ 2013, malloc() and free()

Newsgroups	comp.lang.c
Date	2016-10-25 07:15 -0700
References	<nuiv18$7cr$6@dont-email.me> <50ddf174-e477-4b57-b576-a17623b2ce68@googlegroups.com> <numo37$2l9$3@dont-email.me> <20161025071544.6dd3b8d6@maxa-pc.cpe.bvcom.net>
Message-ID	<b1ed8ae0-cbfb-4e75-8db0-00a222660138@googlegroups.com> (permalink)
Subject	Re: VC++ 2013, malloc() and free()
From	supercat@casperkitty.com

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On Tuesday, October 25, 2016 at 12:15:53 AM UTC-5, Melzzzzz wrote:> > I did some Google Search on this topic. Some claimed that CPU cycles 
> > would be wasted if you called free() in your program given the fact 
> > Window$ would always free the memory a program requested. :)
> > 
> 
> Hm, then GC wastes lot of CPU cycles performing clean up.

Uh, no it doesn't.  Any decent malloc() implementation on a Windows machine
will request memory from the OS in large chunks and then dole it out to the
application in smaller chunks.  Calling free() will add storage into a list
of space that has been received from the operating system and is available
for future calls to malloc().  When a program finishes, the operating
system won't care about what the program has done with its blocks, or what
portions it had marked as available for its own reuse.  The OS will simply
mark all of the "big" blocks it had given to the allocation as available
for reuse.  Although calling free() on every allocated block before exiting
may make it easier to diagnose memory leaks [if a program is expected to
have done so, but some blocks remain allocated, that will indicate that
something that was expected to have been freed, wasn't] and while it's
useful to allow programs to be incorporated into other programs, for the
scenario of a program being run from a typical OS best efficiency would be
obtained by not having applications bothering with free() unless they
themselves are going to have use for the memory released thereby.

Thread

VC++ 2013, malloc() and free() "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-10-24 02:20 +0800
  VC++ 2013, malloc() and free() asetofsymbols@gmail.com - 2016-10-23 11:44 -0700
    Re: VC++ 2013, malloc() and free() "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-10-25 12:46 +0800
      Re: VC++ 2013, malloc() and free() Melzzzzz <mel@zzzzz.com> - 2016-10-25 07:15 +0200
        Re: VC++ 2013, malloc() and free() supercat@casperkitty.com - 2016-10-25 07:15 -0700
          Re: VC++ 2013, malloc() and free() Melzzzzz <mel@zzzzz.com> - 2016-10-25 16:18 +0200
            Re: VC++ 2013, malloc() and free() supercat@casperkitty.com - 2016-10-25 07:32 -0700
              Re: VC++ 2013, malloc() and free() Melzzzzz <mel@zzzzz.com> - 2016-10-25 16:55 +0200
              Re: VC++ 2013, malloc() and free() jameskuyper@verizon.net - 2016-10-25 08:07 -0700
      Re: VC++ 2013, malloc() and free() "Chris M. Thomasson" <invalid@invalid.invalid> - 2016-10-24 22:30 -0700
        Re: VC++ 2013, malloc() and free() Melzzzzz <mel@zzzzz.com> - 2016-10-25 07:46 +0200
          Re: VC++ 2013, malloc() and free() "Chris M. Thomasson" <invalid@invalid.invalid> - 2016-10-25 17:54 -0700
            Re: VC++ 2013, malloc() and free() "Chris M. Thomasson" <invalid@invalid.invalid> - 2016-10-25 17:55 -0700
        Re: VC++ 2013, malloc() and free() "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-10-25 22:32 +0800
          Re: VC++ 2013, malloc() and free() Melzzzzz <mel@zzzzz.com> - 2016-10-25 16:46 +0200
            Re: VC++ 2013, malloc() and free() "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-10-25 23:24 +0800
              Re: VC++ 2013, malloc() and free() "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-10-25 23:52 +0800
          Re: VC++ 2013, malloc() and free() supercat@casperkitty.com - 2016-10-25 08:01 -0700
            Re: VC++ 2013, malloc() and free() Melzzzzz <mel@zzzzz.com> - 2016-10-25 17:23 +0200
              Re: VC++ 2013, malloc() and free() supercat@casperkitty.com - 2016-10-25 09:09 -0700
                Re: VC++ 2013, malloc() and free() Keith Thompson <kst-u@mib.org> - 2016-10-25 09:29 -0700
                Re: VC++ 2013, malloc() and free() Melzzzzz <mel@zzzzz.com> - 2016-10-25 18:51 +0200
                Re: VC++ 2013, malloc() and free() raltbos@xs4all.nl (Richard Bos) - 2016-10-27 19:54 +0000
                Re: VC++ 2013, malloc() and free() supercat@casperkitty.com - 2016-10-27 15:06 -0700
                Re: VC++ 2013, malloc() and free() Keith Thompson <kst-u@mib.org> - 2016-10-27 17:06 -0700
                Re: VC++ 2013, malloc() and free() supercat@casperkitty.com - 2016-10-28 06:47 -0700
                Re: VC++ 2013, malloc() and free() "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-10-29 23:16 +0800
                Re: VC++ 2013, malloc() and free() supercat@casperkitty.com - 2016-10-29 09:35 -0700
                Re: VC++ 2013, malloc() and free() "James R. Kuyper" <jameskuyper@verizon.net> - 2016-10-29 12:51 -0400
                Re: VC++ 2013, malloc() and free() supercat@casperkitty.com - 2016-10-29 14:26 -0700
                Re: VC++ 2013, malloc() and free() jameskuyper@verizon.net - 2016-10-29 15:27 -0700
                Re: VC++ 2013, malloc() and free() supercat@casperkitty.com - 2016-10-29 17:11 -0700
          Re: VC++ 2013, malloc() and free() Geoff <geoff@invalid.invalid> - 2016-10-31 13:01 -0700
            Re: VC++ 2013, malloc() and free() Jerry Stuckle <jstucklex@attglobal.net> - 2016-10-31 16:35 -0400
              Re: VC++ 2013, malloc() and free() "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-11-01 15:31 +0800
                Re: VC++ 2013, malloc() and free() Jerry Stuckle <jstucklex@attglobal.net> - 2016-11-01 11:28 -0400
      Re: VC++ 2013, malloc() and free() Geoff <geoff@invalid.invalid> - 2016-10-31 12:11 -0700
        Re: VC++ 2013, malloc() and free() supercat@casperkitty.com - 2016-10-31 13:08 -0700
  Re: VC++ 2013, malloc() and free() Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-10-23 21:35 +0100
    Re: VC++ 2013, malloc() and free() "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-10-25 12:49 +0800
      Re: VC++ 2013, malloc() and free() Melzzzzz <mel@zzzzz.com> - 2016-10-25 07:16 +0200
        Re: VC++ 2013, malloc() and free() "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-10-25 22:30 +0800
  Re: VC++ 2013, malloc() and free() "Chris M. Thomasson" <invalid@invalid.invalid> - 2016-10-23 15:52 -0700
    Re: VC++ 2013, malloc() and free() "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-10-25 12:50 +0800
      Re: VC++ 2013, malloc() and free() Melzzzzz <mel@zzzzz.com> - 2016-10-25 07:18 +0200
        Re: VC++ 2013, malloc() and free() "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-10-25 22:28 +0800
          Re: VC++ 2013, malloc() and free() Melzzzzz <mel@zzzzz.com> - 2016-10-25 16:48 +0200
            Re: VC++ 2013, malloc() and free() "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-10-25 23:25 +0800
              Re: VC++ 2013, malloc() and free() Melzzzzz <mel@zzzzz.com> - 2016-10-25 17:35 +0200
                Re: VC++ 2013, malloc() and free() "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-10-25 23:50 +0800
                Re: VC++ 2013, malloc() and free() Melzzzzz <mel@zzzzz.com> - 2016-10-25 18:45 +0200
                Re: VC++ 2013, malloc() and free() "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-10-26 01:59 +0800
                Re: VC++ 2013, malloc() and free() Geoff <geoff@invalid.invalid> - 2016-10-31 12:10 -0700
                Re: VC++ 2013, malloc() and free() "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-11-01 15:32 +0800
                Re: VC++ 2013, malloc() and free() Jerry Stuckle <jstucklex@attglobal.net> - 2016-11-01 11:31 -0400
                Re: VC++ 2013, malloc() and free() "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-11-03 19:28 +0800
                Re: VC++ 2013, malloc() and free() Jerry Stuckle <jstucklex@attglobal.net> - 2016-11-03 10:00 -0400
                Re: VC++ 2013, malloc() and free() "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-11-03 23:25 +0800
                Re: VC++ 2013, malloc() and free() Keith Thompson <kst-u@mib.org> - 2016-11-03 09:03 -0700
                [OT] "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-11-04 02:33 +0800
                Re: [OT] Keith Thompson <kst-u@mib.org> - 2016-11-03 12:26 -0700
                Re: [OT] "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-11-04 12:05 +0800
                Re: [OT] luser droog <luser.droog@gmail.com> - 2016-11-03 21:52 -0700
                Re: [OT] "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-11-04 21:59 +0800
                Re: [OT] Keith Thompson <kst-u@mib.org> - 2016-11-04 08:45 -0700
                Re: [OT] James Kuyper <jameskuyper@verizon.net> - 2016-11-04 11:49 -0400
                Re: [OT] "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-11-05 00:33 +0800
                Re: [OT] Keith Thompson <kst-u@mib.org> - 2016-11-04 09:56 -0700
                Re: [OT] "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-11-05 01:40 +0800
                Re: [OT] "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-11-05 01:42 +0800
                Re: [OT] Keith Thompson <kst-u@mib.org> - 2016-11-04 11:52 -0700
                Re: [OT] "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-11-05 18:13 +0800
                Re: [OT] Keith Thompson <kst-u@mib.org> - 2016-11-05 13:19 -0700
                Re: [OT] "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-11-06 16:00 +0800
                Re: VC++ 2013, malloc() and free() Jerry Stuckle <jstucklex@attglobal.net> - 2016-11-03 20:16 -0400
                Re: VC++ 2013, malloc() and free() "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-11-05 00:34 +0800
                Re: VC++ 2013, malloc() and free() supercat@casperkitty.com - 2016-11-03 08:54 -0700
                Re: VC++ 2013, malloc() and free() "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2016-11-04 02:31 +0800

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