Re: Are pointers to virtual member functions unspecified?

From:
=?UTF-8?B?RGFuaWVsIEtyw7xnbGVy?= <daniel.kruegler@googlemail.com>
Newsgroups:
comp.lang.c++.moderated
Date:
Mon, 6 Apr 2015 08:04:01 CST
Message-ID:
<mfrrsm$iah$1@dont-email.me>
Am 05.04.2015 um 17:56 schrieb DeMarcus:

I'm trying to understand C++11 ??5.10.

In ??5.10/1 it says "Pointers of the same type (after pointer
conversions) can be compared for equality".


This part of the wording refers to "just" pointers, such as int*. Your
example below is not related to pointers, it is related to pointers to
members.

In ??5.10/2 it says "Otherwise if either is a pointer to a virtual member
function, the result is unspecified."


This wording is relevant for pointer to members as in your example below.

Consider the following test program.

#include <cassert>

class ISomeClass
{
public:
    virtual ~ISomeClass() {}

    virtual void fnc() = 0;
};

int main()
{
    typedef void(ISomeClass::*MemberPtr)();

    MemberPtr mp = &ISomeClass::fnc;

    assert( mp == &ISomeClass::fnc );

    return 0;
}

Is the assert true or unspecified according to the standard?


It is unspecified, because &ISomeClass::fnc refers to a virtual member
function.

HTH & Greetings from Bremen,

Daniel Kr??gler

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