Referencing "this" from constructor

I have the following situation:

#include <iostream>
#include <boost/bind.hpp>
#include <boost/function.hpp>

class base
{
public:
   base()
   : f(boost::bind(&base::foo,this)){}
   virtual ~base(){}
   virtual void foo() { std::cout << "class base" << std::endl; }
   boost::function<void(void)> f;
};

class a : public base
{
public:
   void foo() { std::cout << "class a" << std::endl; }
};

int main()
{
   base* b = new a();
   b->f();
   return 0;
}

I can guarantee that "f" will never be invoked until "a" has been
instantiated. However I get warnings when compiling, complaining that
accessing "this" during the constructor is a bad idea. I was wondering
what kind of things could go wrong when using "this" during the
constructor, other than some of the more obvious things like accessing
members that haven't been constructed yet etc..

-zenni

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