On Sat, 2007-11-03 at 19:45 -0400, Mike Tegtmeyer wrote:
I guess if shared_ptr was to be done all over again, I think that I would argue that it should act like a pointer, ie you shouldn't be able to 'delete' a 'null' pointer - whatever delete and null mean for
Let's keep shared_ptr like it is. What you (and others) probably need is the right helper, as a quick hack it looks like this: #include <iostream> #include <boost/shared_ptr.hpp> struct X {}; void freeX( X* x ) { // Should not be called with a null pointer std::cout << "free " << x << std::endl; } template< typename T > struct on_nonzero_t { typedef void (&F)( T* ); F f_; on_nonzero_t( F f ) : f_( f ) {} void operator()( T* t ) const { if( t ) f_( t ); } }; template< typename T > on_nonzero_t< T > on_nonzero( void (&f)( T* ) ) { return on_nonzero_t< T >( f ); } void f( X* x ) { std::cout << "x = " << x << std::endl; boost::shared_ptr< X > tmp( x, on_nonzero( freeX ) ); } int main() { X x; f( &x ); f( 0 ); } The naming of the helper might be crap, but anyway, hope you can make some use of it... Regards, Daniel