NULL pointer with boost::shared_ptr?

Question

What\'s the equivalent to the following:

std::vector vec;
vec.push_back(NULL);

when dealing with boost::shared_ptr

Answer 1

You could declare a global nullPtr for shared_ptr. But if you pollute the global namespace, what would you call the global nullPtr for shared_ptr?

Typically I declare the null ptr as a static in the class of the pointer.

#include 

class Foo; // forward decl
typedef boost::shared_ptr FooPtr;
class Foo
{
public:
    static FooPtr Null;
}
...
// define static in cpp file
FooPtr Foo::Null;
...
// use Foo Null
vec.push_back(Foo::Null);

That way each class has a static Null.