Re: templates, constructors, and references

From:

Ulrich Eckhardt <eckhardt@satorlaser.com>

Newsgroups:

comp.lang.c++.moderated

Date:

Tue, 30 Jan 2007 10:27:10 CST

Message-ID:

<ifg394-73q.ln1@satorlaser.homedns.org>

Ross Boylan wrote:

I want to track creation and destruction of objects, so I created a
template that one uses like Count<Foo> to make a class that tracks the
necessary info in static variables. I want this to be a drop-in
replacement for Foo.

If it is to serve that role, it must have the same constructors as Foo.
So I tried

[ctor argument forwarding]

Ross, you could take a different approach and that is to use a 'mixin'
implemented with CRTP. Example:

template<typename T>
class counted_type
{
     counted_type( counted_type const&);
     counted_type& operator=(counted_type const&);
protected:
     counted_type() { ++s_instances; }
     ~counted_type() { --s_instances; }
public:
     static size_t get_count() { return s_instances; }
private:
     static size_t s_instances;
};

class Foo: public counted_type<Foo>
{...};

Uli

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