boost bind or lambda functor that returns a constant

Question

Can I use boost::bind or the boost lambda library to create a functor that ignores its arguments and always returns a constant?

e.g. a functor with equivalent behaviour to:

int returnThree( SomeType arg ) { return 3; }

Answer 1

From Barry's comment on sehe's answer:

#include "boost/lambda/lambda.hpp"

...

auto returnThree = boost::lambda::constant(3);