Re: Simultaneous read and write on a variable in C++

From	Gareth Owen <gwowen@gmail.com>
Newsgroups	comp.lang.c++
Subject	Re: Simultaneous read and write on a variable in C++
References	<ae69a579-bcc6-4583-a40b-83eb33a0bdea@r16g2000yqi.googlegroups.com> <cdba2001-4d1a-4d60-a58c-0dd5c26a9392@m4g2000pbc.googlegroups.com> <47e6756d-03b0-47a7-ad82-93b6ffe14ed3@k8g2000yqk.googlegroups.com> <fc198a11-76c4-40fd-bf53-ac9a9e6c0bf6@b4g2000pbi.googlegroups.com>
Date	2012-01-12 19:36 +0000
Message-ID	<87ipkglnlc.fsf@gmail.com> (permalink)

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Prasoon Saurav <prasoonsaurav.nit@gmail.com> writes:

>> You're not deferencing p, you're dereferencing the result of (p=a)
>> which is (unambiguously) a.
>
> The result of (p=a) is lvalue 'p' with its rvalue 'a'.

"The result of the assignment operation is the value stored in the left
 operand _after the assignment has taken place_; the result is an
 lvalue."  [C++ standard : expr.ass]

"The assignment operators return the value of the object specified by
 the left operand *after the assignment*" (my emphasis)
 http://msdn.microsoft.com/en-us/library/b0zx90af%28v=vs.80%29.aspx

Any other interpretation would make C++ gratuitously 
incompatible with C.

Thread

Simultaneous read and write on a variable in C++ Novice Coder <extngg1@gmail.com> - 2012-01-11 09:08 -0800
  Re: Simultaneous read and write on a variable in C++ Victor Bazarov <v.bazarov@comcast.invalid> - 2012-01-11 12:28 -0500
    Re: Simultaneous read and write on a variable in C++ Victor Bazarov <v.bazarov@comcast.invalid> - 2012-01-12 13:07 -0500
      Re: Simultaneous read and write on a variable in C++ Prasoon Saurav <prasoonsaurav.nit@gmail.com> - 2012-01-12 10:11 -0800
        Re: Simultaneous read and write on a variable in C++ Leigh Johnston <leigh@i42.co.uk> - 2012-01-12 18:46 +0000
          Re: Simultaneous read and write on a variable in C++ Prasoon Saurav <prasoonsaurav.nit@gmail.com> - 2012-01-12 11:18 -0800
            Re: Simultaneous read and write on a variable in C++ Leigh Johnston <leigh@i42.co.uk> - 2012-01-12 19:28 +0000
              Re: Simultaneous read and write on a variable in C++ Leigh Johnston <leigh@i42.co.uk> - 2012-01-12 19:41 +0000
                Re: Simultaneous read and write on a variable in C++ Prasoon Saurav <prasoonsaurav.nit@gmail.com> - 2012-01-12 11:46 -0800
              Re: Simultaneous read and write on a variable in C++ Prasoon Saurav <prasoonsaurav.nit@gmail.com> - 2012-01-12 11:44 -0800
                Re: Simultaneous read and write on a variable in C++ Leigh Johnston <leigh@i42.co.uk> - 2012-01-12 19:46 +0000
                Re: Simultaneous read and write on a variable in C++ Leigh Johnston <leigh@i42.co.uk> - 2012-01-12 19:53 +0000
                Re: Simultaneous read and write on a variable in C++ Prasoon Saurav <prasoonsaurav.nit@gmail.com> - 2012-01-12 12:01 -0800
                Re: Simultaneous read and write on a variable in C++ Leigh Johnston <leigh@i42.co.uk> - 2012-01-12 20:10 +0000
                Re: Simultaneous read and write on a variable in C++ Prasoon Saurav <prasoonsaurav.nit@gmail.com> - 2012-01-12 12:13 -0800
                Re: Simultaneous read and write on a variable in C++ Leigh Johnston <leigh@i42.co.uk> - 2012-01-12 20:31 +0000
                Re: Simultaneous read and write on a variable in C++ scott@slp53.sl.home (Scott Lurndal) - 2012-01-13 18:12 +0000
              Re: Simultaneous read and write on a variable in C++ Prasoon Saurav <prasoonsaurav.nit@gmail.com> - 2012-01-12 11:37 -0800
                Re: Simultaneous read and write on a variable in C++ Leigh Johnston <leigh@i42.co.uk> - 2012-01-12 19:56 +0000
                Re: Simultaneous read and write on a variable in C++ Prasoon Saurav <prasoonsaurav.nit@gmail.com> - 2012-01-12 11:58 -0800
                Re: Simultaneous read and write on a variable in C++ Leigh Johnston <leigh@i42.co.uk> - 2012-01-12 20:04 +0000
              Re: Simultaneous read and write on a variable in C++ Juha Nieminen <nospam@thanks.invalid> - 2012-01-13 06:34 +0000
  Re: Simultaneous read and write on a variable in C++ SG <s.gesemann@gmail.com> - 2012-01-11 13:11 -0800
  Re: Simultaneous read and write on a variable in C++ Calum <spambox@calumgrant.net> - 2012-01-11 13:18 -0800
  Re: Simultaneous read and write on a variable in C++ Prasoon Saurav <prasoonsaurav.nit@gmail.com> - 2012-01-12 03:11 -0800
    Re: Simultaneous read and write on a variable in C++ "Fred Zwarts \(KVI\)" <F.Zwarts@KVI.nl> - 2012-01-12 16:35 +0100
      Re: Simultaneous read and write on a variable in C++ Prasoon Saurav <prasoonsaurav.nit@gmail.com> - 2012-01-12 08:06 -0800
    Re: Simultaneous read and write on a variable in C++ gwowen <gwowen@gmail.com> - 2012-01-12 07:48 -0800
      Re: Simultaneous read and write on a variable in C++ Prasoon Saurav <prasoonsaurav.nit@gmail.com> - 2012-01-12 07:55 -0800
        Re: Simultaneous read and write on a variable in C++ Gareth Owen <gwowen@gmail.com> - 2012-01-12 19:36 +0000
          Re: Simultaneous read and write on a variable in C++ Victor Bazarov <v.bazarov@comcast.invalid> - 2012-01-12 16:31 -0500
    Re: Simultaneous read and write on a variable in C++ Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-01-13 02:05 -0800
    Re: Simultaneous read and write on a variable in C++ Goran <goran.pusic@gmail.com> - 2012-01-13 04:24 -0800
      Re: Simultaneous read and write on a variable in C++ Prasoon Saurav <prasoonsaurav.nit@gmail.com> - 2012-01-13 04:52 -0800
  Re: Simultaneous read and write on a variable in C++ Leigh Johnston <leigh@i42.co.uk> - 2012-01-12 12:39 +0000
  Re: Simultaneous read and write on a variable in C++ Leigh Johnston <leigh@i42.co.uk> - 2012-01-12 12:50 +0000
    Re: Simultaneous read and write on a variable in C++ Leigh Johnston <leigh@i42.co.uk> - 2012-01-12 12:58 +0000
      Re: Simultaneous read and write on a variable in C++ Prasoon Saurav <prasoon@parallocity.com> - 2012-01-12 05:55 -0800
        Re: Simultaneous read and write on a variable in C++ Leigh Johnston <leigh@i42.co.uk> - 2012-01-12 13:59 +0000
          Re: Simultaneous read and write on a variable in C++ Prasoon Saurav <prasoon@parallocity.com> - 2012-01-12 06:14 -0800
            Re: Simultaneous read and write on a variable in C++ Leigh Johnston <leigh@i42.co.uk> - 2012-01-12 14:30 +0000
            Re: Simultaneous read and write on a variable in C++ Juha Nieminen <nospam@thanks.invalid> - 2012-01-12 14:34 +0000
    Re: Simultaneous read and write on a variable in C++ Prasoon Saurav <prasoon@parallocity.com> - 2012-01-12 05:54 -0800
  Re: Simultaneous read and write on a variable in C++ BCFD36 <bcfd36@cruzio.com> - 2012-01-14 01:52 -0800

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