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Groups > comp.lang.c > #53846

Re: "lvalue"

From Keith Thompson <kst-u@mib.org>
Newsgroups comp.lang.c
Subject Re: "lvalue"
Date 2014-12-03 23:40 -0800
Organization None to speak of
Message-ID <lnmw73q2vi.fsf@nuthaus.mib.org> (permalink)
References (1 earlier) <m5nhhr$qda$1@dont-email.me> <m5nkqb$6qk$1@speranza.aioe.org> <m5nml1$gho$1@dont-email.me> <547F72A6.8030502@verizon.net> <lvalue-20141204013653@ram.dialup.fu-berlin.de>

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ram@zedat.fu-berlin.de (Stefan Ram) writes:
> James Kuyper <jameskuyper@verizon.net> writes:
>>Those two statements cannot both be true. The current standard is
>>intended to identify *p as an lvalue, even if p has a null or
>>indeterminate value, in which case *p does NOT refer to an object. C90's
>
>   An attempt by me:
>
>       »An expression is an /lvalue expression/,
>       if it has the form
>
>         v,
>
>       where v is a variable or a parameter,
>       or if it has the form
>
>         *E,
>
>       where E is an expression of pointer type
>       (or an equivalent expression written with
>       the [] operator)«

The standard doesn't define the word "variable".  The word "object"
covers both declared variables and parameters.  An identifier is an
lvalue if and only if it's an object name.

A parenthesized lvalue is an lvalue.

*E is an lvalue only if E is of object pointer type; if E is a function
pointer, *E is not an lvalue.

A string literal is an lvalue.

X.Y, where X is an lvalue of struct or union type, is an lvalue.

A compound literal is an lvalue.

And as you said, *E or E1[E2] is an lvalue.

I think that covers it, but I'm not certain.

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"

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Re: "lvalue" buja <buja66@gmail.com> - 2014-12-03 18:34 +0100
  Re: "lvalue" James Kuyper <jameskuyper@verizon.net> - 2014-12-03 13:03 -0500
  Re: "lvalue" jacob navia <jacob@spamsink.net> - 2014-12-03 19:29 +0100
    Re: "lvalue" buja <buja66@gmail.com> - 2014-12-03 20:01 +0100
      Re: "lvalue" Keith Thompson <kst-u@mib.org> - 2014-12-03 12:18 -0800
      Re: "lvalue" Geoff <geoff@invalid.invalid> - 2014-12-03 12:20 -0800
      Re: "lvalue" James Kuyper <jameskuyper@verizon.net> - 2014-12-03 15:29 -0500
        Re: "lvalue" James Kuyper <jameskuyper@verizon.net> - 2014-12-03 21:48 -0500
          Re: "lvalue" Keith Thompson <kst-u@mib.org> - 2014-12-04 08:20 -0800
            Re: "lvalue" James Kuyper <jameskuyper@verizon.net> - 2014-12-04 11:44 -0500
              Re: "lvalue" Keith Thompson <kst-u@mib.org> - 2014-12-04 11:41 -0800
                Re: "lvalue" James Kuyper <jameskuyper@verizon.net> - 2014-12-04 14:50 -0500
        Re: "lvalue" Keith Thompson <kst-u@mib.org> - 2014-12-03 23:40 -0800
    Re: "lvalue" Tim Rentsch <txr@alumni.caltech.edu> - 2014-12-05 09:16 -0800

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