annonymous — Thu, 06 Nov 2008 00:06:19 GMT

Okay, so this isn't a problem with ptr_container per-se but rather a bug with MSVC, which might also manifest itself in other parts of the library. I'm posting a workaround that should fix the problem, but I still believe it should be taken into account and fixed in a future release.

// ---------------------------------------------------------------------------------------
//  Fix for a bug in MSVC++ that made sort fail on ptr_containers which held pointers
//  to abstract types. Include and use sort_ptr_container(ptr_container [, function]).
//  Thanks goes to Dodheim who originally came up with this fix :-)
// ---------------------------------------------------------------------------------------
#include <algorithm>
#include <boost/type_traits/remove_pointer.hpp>
template<typename Fun, typename Arg>
class indirect_compare
{
private:
        Fun fun;
public:
        typedef bool result_type;
        indirect_compare() : fun(Fun()) {}
        indirect_compare(Fun f) : fun(f) {}
        result_type operator ()(const void* lhs, const void* rhs) const
        {
                return fun(*static_cast<const Arg*>(lhs), *static_cast<const Arg*>(rhs));
        }
};
template<typename container_t>
void sort_ptr_container(container_t& container)
{
        typedef typename boost::remove_pointer<typename container_t::value_type>::type Arg;
        sort_ptr_container(container, std::less<Arg>());
}
template<typename container_t, typename Fun>
void sort_ptr_container(container_t& container, Fun f)
{
        typedef typename boost::remove_pointer<typename container_t::value_type>::type Arg;
        std::sort(container.begin().base(), container.end().base(), indirect_compare<Fun, Arg>(f));
}

anonymous — Thu, 06 Nov 2008 02:50:03 GMT

Some more information. It seems that the problem resides with boost::result_of<F> being called as boost::result_of<F(AbstractType, AbstractType)>, even though F takes AbstractType& as argument. This doesn't compile in Microsoft Visual C++ 2008, though it has been said to work in some other compilers.

status changed; resolution set

Thorsten Ottosen — Tue, 17 Feb 2009 22:53:17 GMT

status new → closed
resolution → fixed

Boost C++ Libraries: Ticket #2472: ptr_sequence_adapter::sort fails to compile if T is an abstract base class

status changed; resolution set