Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > comp.lang.c > #28866

Re: What's new in C?

From Eric Sosman <esosman@comcast-dot-net.invalid>
Newsgroups comp.lang.c
Subject Re: What's new in C?
Date 2012-11-30 15:52 -0500
Organization A noiseless patient Spider
Message-ID <k9b6a7$lb4$1@dont-email.me> (permalink)
References (2 earlier) <k98ak3$ts6$1@dont-email.me> <k9a2qf$mbh$1@dont-email.me> <028418c2-2b87-47ce-8727-f73fcd408309@googlegroups.com> <k9ahtc$ahl$1@dont-email.me> <k9anj1$iap$1@speranza.aioe.org>

Show all headers | View raw


On 11/30/2012 11:41 AM, glen herrmannsfeldt wrote:
>
> Is it required that VLAs be stack allocated?

     No.  One plausible approach would be to malloc() space
for the array and insert a compiler-generated free() at block
exit.  This could be trickier than might appear at first glance,
though, since the block might exit via longjmp().

     Another possibility is to defer deallocation until some
convenient later time, like the next time a VLA is created.
VLA memory could be obtained from malloc() and appended to a
LIFO linked list of such areas, tagged with the "stack depth"
of the requestor.  At the next VLA allocation, the new requestor's
depth is determined and any areas allocated at deeper levels are
discarded.  (A semi-portable alloca() replacement by DA Gwyn
works this way.)  This could be combined with the first approach
to provide a safety net for the longjmp() case.

-- 
Eric Sosman
esosman@comcast-dot-net.invalid

Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread


Thread

What's new in C? Cal Dershowitz <cal@example.invalid> - 2012-11-28 19:41 -0700
  Re: What's new in C? Keith Thompson <kst-u@mib.org> - 2012-11-28 19:15 -0800
    Re: What's new in C? Cal Dershowitz <cal@example.invalid> - 2012-12-06 02:43 -0700
      Re: What's new in C? James Kuyper <jameskuyper@verizon.net> - 2012-12-06 07:45 -0500
  Re: What's new in C? Noob <root@127.0.0.1> - 2012-11-29 10:36 +0100
    Re: What's new in C? Weland <weland@sdf.lonestar.org> - 2012-11-29 10:17 +0000
    Re: What's new in C? Cal Dershowitz <cal@example.invalid> - 2012-12-04 01:45 -0700
  Re: What's new in C? Weland <weland@sdf.lonestar.org> - 2012-11-29 09:48 +0000
    Re: What's new in C? David Brown <david@westcontrol.removethisbit.com> - 2012-11-29 13:50 +0100
  Re: What's new in C? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-11-29 05:55 -0800
    Re: What's new in C? Les Cargill <lcargill99@comcast.com> - 2012-11-29 12:48 -0600
      Re: What's new in C? Rui Maciel <rui.maciel@gmail.com> - 2012-11-30 10:46 +0000
        Re: What's new in C? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-11-30 05:31 -0800
          Re: What's new in C? "BartC" <bc@freeuk.com> - 2012-11-30 14:22 +0000
          Re: What's new in C? Rui Maciel <rui.maciel@gmail.com> - 2012-11-30 15:04 +0000
            Re: What's new in C? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-11-30 16:41 +0000
              Re: What's new in C? James Kuyper <jameskuyper@verizon.net> - 2012-11-30 11:49 -0500
              Re: What's new in C? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-11-30 10:12 -0800
              Re: What's new in C? Keith Thompson <kst-u@mib.org> - 2012-11-30 11:12 -0800
                Re: What's new in C? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-11-30 22:26 +0000
                Re: What's new in C? "BartC" <bc@freeuk.com> - 2012-11-30 22:36 +0000
                Re: What's new in C? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-11-30 23:27 +0000
                Re: What's new in C? Cal Dershowitz <cal@example.invalid> - 2012-12-04 01:39 -0700
                Re: What's new in C? Keith Thompson <kst-u@mib.org> - 2012-12-04 00:43 -0800
                Re: What's new in C? Cal Dershowitz <cal@example.invalid> - 2012-12-04 03:14 -0700
                Re: What's new in C? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-12-04 12:50 +0000
                Re: What's new in C? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-12-04 05:54 -0800
                Re: What's new in C? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-04 20:51 +0000
                Re: What's new in C? Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-12-04 16:09 -0500
                Re: What's new in C? James Kuyper <jameskuyper@verizon.net> - 2012-12-04 16:19 -0500
                Re: What's new in C? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-12-04 21:45 +0000
                Re: What's new in C? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-05 01:13 +0000
                Re: What's new in C? James Kuyper <jameskuyper@verizon.net> - 2012-12-04 20:36 -0500
                Re: What's new in C? Robert Wessel <robertwessel2@yahoo.com> - 2012-12-04 20:26 -0600
                Re: What's new in C? Keith Thompson <kst-u@mib.org> - 2012-12-04 18:48 -0800
                Re: What's new in C? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-12-05 02:57 +0000
                Re: What's new in C? "BartC" <bc@freeuk.com> - 2012-12-05 01:42 +0000
                Re: What's new in C? Cal Dershowitz <cal@example.invalid> - 2012-12-06 02:06 -0700
                Re: What's new in C? James Kuyper <jameskuyper@verizon.net> - 2012-12-06 07:50 -0500
                Re: What's new in C? JohnF <john@please.see.sig.for.email.com> - 2012-12-06 13:46 +0000
                Re: What's new in C? James Kuyper <jameskuyper@verizon.net> - 2012-12-06 09:39 -0500
              Re: What's new in C? Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-11-30 15:52 -0500
                Re: What's new in C? Cal Dershowitz <cal@example.invalid> - 2012-12-04 01:53 -0700
                Re: What's new in C? Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-12-04 08:16 -0500
                Re: What's new in C? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-04 21:18 +0000
                Re: What's new in C? Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-12-04 18:04 -0500
                Re: What's new in C? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-05 01:19 +0000
                Re: What's new in C? Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-12-04 21:05 -0500
                Re: What's new in C? Noob <root@127.0.0.1> - 2012-12-05 16:45 +0100
                Re: What's new in C? Cal Dershowitz <cal@example.invalid> - 2012-12-06 01:45 -0700
                Re: What's new in C? James Kuyper <jameskuyper@verizon.net> - 2012-12-06 08:12 -0500
                Re: What's new in C? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-06 21:13 +0000
                Re: What's new in C? Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-12-06 09:15 -0500
                Re: What's new in C? Cal Dershowitz <cal@example.invalid> - 2012-12-12 18:28 -0700
        Re: What's new in C? Keith Thompson <kst-u@mib.org> - 2012-11-30 11:22 -0800
          Re: What's new in C? Cal Dershowitz <cal@example.invalid> - 2012-12-04 03:04 -0700
  Re: What's new in C? Rui Maciel <rui.maciel@gmail.com> - 2012-11-29 18:19 +0000
    Re: What's new in C? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-11-29 11:41 -0800
  Re: What's new in C? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-11-30 20:50 +0000
    Re: What's new in C? Jens Gustedt <jens.gustedt@loria.fr> - 2012-11-30 23:35 +0100
      Re: What's new in C? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-12-05 03:26 +0000
        Re: What's new in C? gwowen <gwowen@gmail.com> - 2012-12-05 23:49 -0800
          Re: What's new in C? Cal Dershowitz <cal@example.invalid> - 2012-12-06 01:49 -0700
          Re: What's new in C? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-12-08 07:55 +0000
            Re: What's new in C? "BartC" <bc@freeuk.com> - 2012-12-08 13:29 +0000
              Re: What's new in C? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-12-08 15:23 +0000
                Re: What's new in C? Martin Shobe <martin.shobe@yahoo.com> - 2012-12-08 17:46 +0000
                Re: What's new in C? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-12-08 10:45 -0800
                Re: What's new in C? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-12-08 19:32 +0000
                Re: What's new in C? "BartC" <bc@freeuk.com> - 2012-12-08 18:55 +0000
                Re: What's new in C? Ian Collins <ian-news@hotmail.com> - 2012-12-09 08:26 +1300
                Re: What's new in C? "BartC" <bc@freeuk.com> - 2012-12-08 20:12 +0000
                Re: What's new in C? Ian Collins <ian-news@hotmail.com> - 2012-12-09 09:18 +1300
                Re: What's new in C? "BartC" <bc@freeuk.com> - 2012-12-08 21:21 +0000
                Re: What's new in C? Ian Collins <ian-news@hotmail.com> - 2012-12-09 10:27 +1300
                Re: What's new in C? Keith Thompson <kst-u@mib.org> - 2012-12-08 13:36 -0800
                Re: What's new in C? Keith Thompson <kst-u@mib.org> - 2012-12-08 12:59 -0800
                Re: What's new in C? "BartC" <bc@freeuk.com> - 2012-12-08 22:10 +0000
                Re: What's new in C? Keith Thompson <kst-u@mib.org> - 2012-12-08 16:15 -0800
                Re: What's new in C? Ian Collins <ian-news@hotmail.com> - 2012-12-09 14:23 +1300
                Re: What's new in C? Ian Collins <ian-news@hotmail.com> - 2012-12-09 14:20 +1300
                Re: What's new in C? Keith Thompson <kst-u@mib.org> - 2012-12-08 11:32 -0800
                Re: What's new in C? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-12-09 02:52 +0000
                Re: What's new in C? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-12-09 02:53 +0000
                Re: What's new in C? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-12-08 20:08 +0000
                Re: What's new in C? "BartC" <bc@freeuk.com> - 2012-12-08 20:25 +0000

csiph-web