Re: Address of member in class scope

From:
"=?iso-8859-1?q?Daniel_Kr=FCgler?=" <daniel.kruegler@googlemail.com>
Newsgroups:
comp.std.c++
Date:
Fri, 23 Mar 2007 00:44:01 CST
Message-ID:
<1174604445.857748.33160@e65g2000hsc.googlegroups.com>
jam schrieb:

multiple virtual inheitance postpones the calculation of data members`
address to runtime using dynamic typing and for this I guess that many
implementations assume all data member addresses to be evaluated at
runtime


1) According to 14.3.2/1 a pointer to member is a valid argument
for a non-type template.

2) According to 5.19/2+4 we have the concept of a "pointer to
member constant expression":

"A pointer to member constant expression shall be created using
the unary & operator applied to a qualifiedid operand (5.3.1),
optionally preceded by a pointer to member cast (5.2.9)."

which is one of the valid components of a constant expression
capable to initialize a non-local static object. Exactly this kind of
initialization belongs to the static initializations occuring
*before*
dynamic initialization takes place.

Both (1) and (2) are *static* accesses to a pointer of member
and exactly this kind has been performed by the OP. This has
nothing to do with possible dynamic typing. Similarily I can
aquire the static address of a pure, virtual member function,
although those are usually known as pure incarnations of
runtime entities:

struct V {
  virtual ~V() = 0;
  virtual void foo() = 0;
};

template < void (V::*)() >
struct Tester {};

int main() {
  Tester<&V::foo>(); // No problem -> Static access
}

(Btw.: The above program compiles successfully for all
three compiler's tested in my previous posting, *even*
for VS2005-SP1)

Greetings from Bremen,

Daniel Kr?gler

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