Re: c++/10086: static const int unresolved in ? : construct

[Gabriel Dos Reis <gdr@integrable-solutions.net>]

The following reply was made to PR c++/10086; it has been noted by GNATS.

From: Gabriel Dos Reis <gdr@integrable-solutions.net>
To: "Giovanni Bajo" <giovannibajo@libero.it>
Cc: <gcc-gnats@gcc.gnu.org>, <gcc-bugs@gcc.gnu.org>, <chrisk@mysticlabs.com>
Subject: Re: c++/10086: static const int unresolved in ? : construct
Date: 16 Mar 2003 10:28:29 +0100

 "Giovanni Bajo" <giovannibajo@libero.it> writes:
 
 | http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&p
 | r=10086
 
 I think arguments can be made for both sides (bug or not a bug) in
 this particular case.  Certainly understand what is going on involves
 understanding how the compiler is treating internal the expression 
 
     v ? A : B
 
 Certainly, it is not an integrable constant expression and it is an
 lvalue.  Wihch means the compiler is internally taking the address of
 both Base::A and Base::B.  Hence the link error.
 
 | I'm not sure what it is going on. I know that the standard says that you
 | still have to define an initialized static const member (even if there is an
 | open defect report about this, I believe). But then, why this should work:
 | 
 | struct Foo
 | {
 |    static const int A = 0;
 | };
 | 
 | int main(void)
 | {
 |    return Foo::A;
 | }
 | 
 | This one compiles and links correctly on G++ 3.2, but it should not. 
 
 In the above, Foo::A is used in a such way that its definition isn't
 needed, i.e. its address isn't taken.
 
 I agree with you that all that is confusing.  A reason why I've always
 thought of that as a misfeature -- it doesn't scale easily.
 
 -- Gaby