Re: [Boost-users] [bind] using NULL as a bound argument

Marc Horowitz:

I am attempting to use Boost.Bind to create a callable where some of the bound arguments might be NULL. Here is a simple example:

void f(const char *) {}

int main() { (std::tr1::bind(f, _1))(NULL);

return(0); }

This is indeed annoying. I've also been using

class NullPlaceholder { public: template <class T> operator T*() const { return((T*)NULL); } };

NullPlaceholder _NULL;

except not calling it _NULL since this name is reserved. We should probably have boost/nullptr.hpp that defines the macro nullptr to something like (::boost::nullptr_t()) in C++03 mode and does nothing otherwise (as C++0x will have a nullptr keyword.) shared_ptr will also need a nullptr_t type when it's updated to match the C++0x interface.