Re: address of virtual member function passed as template argument

From:
"Alex Blekhman" <xfkt@oohay.moc>
Newsgroups:
microsoft.public.vc.language
Date:
Mon, 19 Mar 2007 01:10:34 +0200
Message-ID:
<OQamgKbaHHA.1244@TK2MSFTNGP04.phx.gbl>
<pascal.zschumme@gmail.com> wrote:

[...]
I want to use Boost.Property and therefor it need to pass
those
addresses to boost::property::object_property<...>

consider the following example:
<code>
class foo
{
private:
int value;

public:
int getValue() const { return value; }
void setValue(const int& v) { value = v; }

boost::scalar_property< boost::object_property
<
char, foo,
&foo::getValue,
&foo::setValue

Value;

};
</code>

If you make getValue() oder setValue() virtual, it
crashes.
Well, i could pass pointers to getValue and setValue to
the property
using it's custuctor at RunTime.
But i had to write my own property-lib for that and (more
importantly)
it wouldn't fit into my OOP-system that well. (would be
better if
every devired class _had_ to use getValue and setValue for
their
properties)


I'm not sure whether following code will fit into your
OOP-system or not, but here's the possible solution using
VC++ specific extension:

<code>

class foo
{
private:
 int value;

public:
 virtual int getValue() const { return value; }
 virtual void setValue(const int& v) { value = v; }

    __declspec(property(
        get = getValue, put = setValue)) int Value;
};

....

foo f;
f.Value = 42; // foo::setValue is called

</code>

Alex

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