On 12/4/2012 2:21 PM, Jeffrey Lee Hellrung, Jr. wrote:
On Tue, Dec 4, 2012 at 2:14 PM, Peter Dimov <lists@pdimov.com> wrote:
Eric Niebler wrote:
... until some other library ALSO defines a global nullptr symbol, making that library and boost mutually incompatible.
How is the end user supposed to actually use nullptr if it's not global? It's a keyword in C++11; boost::nullptr is not legal.
namespace X {
BOOST_USING_NULLPTR;
void foo() { int * p = nullptr; }
} // namespace X
is the basic usage I had proposed. BOOST_USING_NULLPTR expands to some empty statement in C++11 and "using ::boost::nullptr" in C++03.
Right. In my understanding, it could work like this: // Some stupid lib does this: constexpr struct mynullptr_t {} mynullptr {}; // Boost does this: namespace boost { constexpr struct mynullptr_t {} mynullptr {}; } #define BOOST_USING_NULLPTR \ using boost::mynullptr_t; \ using boost::mynullptr // Third-party code does this: namespace my { BOOST_USING_NULLPTR; void foo() { mynullptr_t x; x = mynullptr; } } No ambiguity. -- Eric Niebler BoostPro Computing http://www.boostpro.com