Re: copy/pass a va_list to another thread

From	BGB <cr88192@hotmail.com>
Newsgroups	comp.lang.c++
Subject	Re: copy/pass a va_list to another thread
Date	2012-03-08 09:25 -0700
Organization	albasani.net
Message-ID	<jjaml8$evb$1@news.albasani.net> (permalink)
References	<15783154.7098.1331159818084.JavaMail.geo-discussion-forums@vbgu10>

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On 3/7/2012 3:36 PM, Christopher wrote:
> Working on a pre-existing interface that I am not allowed to change, which uses a va_list argument. The method takes way too long to execute and is a canidate for splitting off into another thread. However, I am not sure how I can safely copy the va_list without actually processing its real components. The processing into its real components is a good chunk of what is taking too long.
>
> Any ideas on how to safely pass a varibale argument list to another thread to be processed?

no, va_list can't be safely passed (given they depend on the callers' 
stack frame, which is thread-local).

best option I know of:
read arguments from va_list into some other format (such as an array);
pass a copy of this data instead.

granted, this requires some means to know the layout of the list in 
advance (number and types of arguments), which is presumably available 
somehow?

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copy/pass a va_list to another thread Christopher <cpisz@austin.rr.com> - 2012-03-07 14:36 -0800
  Re: copy/pass a va_list to another thread "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2012-03-08 02:04 +0100
    Re: copy/pass a va_list to another thread Christopher <cpisz@austin.rr.com> - 2012-03-08 11:54 -0800
      Re: copy/pass a va_list to another thread "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2012-03-08 21:41 +0100
        Re: copy/pass a va_list to another thread Christopher <cpisz@austin.rr.com> - 2012-03-08 13:56 -0800
          OT: Free Usenet Access red floyd <no.spam.here@its.invalid> - 2012-03-08 16:09 -0800
            Re: OT: Free Usenet Access Christopher Pisz <someone@somewhere.net> - 2012-03-09 10:26 -0600
          New Google Groups problems (was Re: copy/pass a va_list to another thread) Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-03-09 12:27 +0000
          Re: copy/pass a va_list to another thread Robert Miles <milesrf@Usenet-News.net> - 2012-04-21 23:43 -0500
            XSUsenet.COM  @Jeff-Relf.Me - 2012-04-21 22:12 -0700
        Re: copy/pass a va_list to another thread Miles Bader <miles@gnu.org> - 2012-03-10 05:12 +0900
          Re: copy/pass a va_list to another thread "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2012-03-10 00:00 +0100
            Re: copy/pass a va_list to another thread Miles Bader <miles@gnu.org> - 2012-03-10 08:40 +0900
              Re: copy/pass a va_list to another thread Miles Bader <miles@gnu.org> - 2012-03-10 08:42 +0900
              MIME (Re: copy/pass a va_list to another thread) Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-03-10 07:04 +0000
                Re: MIME (Re: copy/pass a va_list to another thread) Miles Bader <miles@gnu.org> - 2012-03-10 16:56 +0900
                Re: MIME (Re: copy/pass a va_list to another thread) Gareth Owen <gwowen@gmail.com> - 2012-03-11 07:37 +0000
              Re: copy/pass a va_list to another thread "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2012-03-10 10:44 +0100
                Re: copy/pass a va_list to another thread Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-03-10 14:43 +0000
                Re: copy/pass a va_list to another thread "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2012-03-10 21:17 +0100
                Re: copy/pass a va_list to another thread Miles Bader <miles@gnu.org> - 2012-03-11 10:49 +0900
                Re: copy/pass a va_list to another thread Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-03-11 07:11 +0000
                Re: copy/pass a va_list to another thread Miles Bader <miles@gnu.org> - 2012-03-11 19:03 +0900
                Re: copy/pass a va_list to another thread Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-03-11 11:49 +0000
                Re: copy/pass a va_list to another thread Miles Bader <miles@gnu.org> - 2012-03-11 23:01 +0900
                Re: copy/pass a va_list to another thread "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2012-03-11 18:25 +0100
                Re: copy/pass a va_list to another thread Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-03-11 23:53 +0000
            Re: copy/pass a va_list to another thread Mike McCarty <mcmccarty@gmail.com> - 2012-03-10 05:47 -0800
              Re: copy/pass a va_list to another thread Dombo <dombo@disposable.invalid> - 2012-03-10 19:51 +0100
                Re: copy/pass a va_list to another thread "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2012-03-10 21:23 +0100
                Re: copy/pass a va_list to another thread Dombo <dombo@disposable.invalid> - 2012-03-11 14:36 +0100
                Re: copy/pass a va_list to another thread "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2012-03-11 18:33 +0100
                Re: copy/pass a va_list to another thread Dombo <dombo@disposable.invalid> - 2012-03-11 20:41 +0100
                Re: copy/pass a va_list to another thread "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2012-03-11 21:49 +0100
                Re: copy/pass a va_list to another thread Rui Maciel <rui.maciel@gmail.com> - 2012-03-11 17:18 +0000
                Re: copy/pass a va_list to another thread "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2012-03-11 18:39 +0100
                Re: copy/pass a va_list to another thread Rui Maciel <rui.maciel@gmail.com> - 2012-03-11 18:54 +0000
                Re: copy/pass a va_list to another thread Christian Gollwitzer <auriocus@gmx.de> - 2012-03-12 19:03 +0100
              Re: copy/pass a va_list to another thread Rui Maciel <rui.maciel@gmail.com> - 2012-03-11 17:09 +0000
          Re: copy/pass a va_list to another thread scott@slp53.sl.home (Scott Lurndal) - 2012-03-11 01:26 +0000
            Re: copy/pass a va_list to another thread Miles Bader <miles@gnu.org> - 2012-03-11 11:18 +0900
              Re: copy/pass a va_list to another thread scott@slp53.sl.home (Scott Lurndal) - 2012-03-11 16:41 +0000
      Re: copy/pass a va_list to another thread scott@slp53.sl.home (Scott Lurndal) - 2012-03-08 23:07 +0000
      Re: copy/pass a va_list to another thread Paavo Helde <myfirstname@osa.pri.ee> - 2012-03-08 23:17 -0600
      Re: copy/pass a va_list to another thread Stuart Redmann <DerTopper@web.de> - 2012-03-10 05:10 -0800
      Re: copy/pass a va_list to another thread 88888 Dihedral <dihedral88888@googlemail.com> - 2012-03-10 05:42 -0800
      Re: copy/pass a va_list to another thread Robert Miles <milesrf@Usenet-News.net> - 2012-04-21 23:20 -0500
  Re: copy/pass a va_list to another thread BGB <cr88192@hotmail.com> - 2012-03-08 09:25 -0700

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