Re: Why can't a pure virtual function have an inline definition?

From:

red floyd <redfloyd@gmail.com>

Newsgroups:

comp.lang.c++.moderated

Date:

Thu, 16 Sep 2010 12:03:47 CST

Message-ID:

<284a3cf3-c74f-466b-90d8-64c5e649465e@c32g2000vbq.googlegroups.com>

On Sep 15, 9:27 am, Frank Buss <f...@frank-buss.de> wrote:

armen.tsirunyan wrote:

It is clearly stated in the current C++ International Standard (2003)
that no virtual function declaration shall contain both a pure
specifier and a definition. I wonder what is the reason of prohibiting
this? I mean, the feature is obviously trivial to implement, it is
more uniform and, well, quite useful. So what considerations am I
missing? Thank you.

This is the same as in the ISO IEC 14882-1999, see chapter 10.4.2, and it
makes sense, because the idea of a "pure virtual" function is, that there
is no definition, so why do you think it would be useful? Providing a
defintion for a virtual function might be useful, but I don't see how it
would make sense for pure virtual functions.
=

Pure virtual destructors are allowed, yet must have definitions:

struct base {
    virtual ~base() = 0;
};

base::~base() { }

struct derived : public base {
};

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