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From: Keith Thompson <kst-u@mib.org>
Newsgroups: comp.lang.c
Subject: Re: lvalues from the ternary op
Date: Wed, 04 Jan 2017 15:21:46 -0800
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supercat@casperkitty.com writes:
> On Wednesday, January 4, 2017 at 3:48:34 PM UTC-6, Keith Thompson wrote:
>> For example, this:
>> 
>>     int x;
>>     double y;
>>     (condition ? x : y) = 42;
>> 
>> would be difficult to implement sensibly.  Taking the address of a
>> ternary expression would be even more difficult.  (C++ already does
>> this; I haven't checked the standard's wording.)
>
> The Standard already includes type resolution rules for condition?p:q where
> p and q are pointers.  If the result of the conditional expression is used
> as an object, is there any reason the type resolution rules for
> *(condition ? &x : &y) couldn't be used for (condition ? x : y), but with
> the proviso that if the address of the expression isn't taken, x and y need
> not be regarded as having had their addresses taken by the expression, would
> not be adequate?

No reason I can think of (but I'd probably phrase the proviso
differently).  Of course (condition ? x : y) in the example above still
wouldn't be an lvalue.

-- 
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"