ambiguous

From:

Tim H <thockin@gmail.com>

Newsgroups:

comp.lang.c++

Date:

Fri, 15 Jun 2007 05:21:07 -0000

Message-ID:

<1181884867.199083.249920@d30g2000prg.googlegroups.com>

Why is this ambiguous:

------------------------------------------------
#include <boost/shared_ptr.hpp>

class base {};
class derived: public base {};
class other {};

void do_something(const boost::shared_ptr<other> dev) {}
void do_something(const boost::shared_ptr<base> scope) {}

int main()
{
        boost::shared_ptr<base> b(new base());
        boost::shared_ptr<derived> d(new derived());

        do_something(b);
        do_something(d);

        return 0;
}
------------------------------------------------

but this is not

------------------------------------------------
class base {};
class derived: public base {};
class other {};

void do_something(const other *dev) {}
void do_something(const base *scope) {}

int main()
{
        base *b = new base();
        derived *d = new derived();

        do_something(b);
        do_something(d);

        return 0;
}
-------------------------------------------------------

and this is also allowed

------------------------------------------------------
#include <boost/shared_ptr.hpp>

class base {};
class derived: public base {};
class other {};

void do_something(const boost::shared_ptr<base> scope) {}

int main()
{
        boost::shared_ptr<base> b(new base());
        boost::shared_ptr<derived> d(new derived());

        do_something(b);
        do_something(d);

        return 0;
}
--------------------------------------------------------------------

Thanks!

Tim