----- Mensaje original ----- De: Alexei Alexandrov <alexei.alexandrov@gmail.com> Fecha: Miércoles, Abril 12, 2006 7:17 pm Asunto: Re: [boost][multi_index] Problems with chained pointers in multi index from 1.34 RC

JOAQUIN LOPEZ MU?Z <joaquin <at> tid.es> writes:

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1. What is the compiler error you're getting?

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Now, from what you report, seems the restriction is being too much comprehensive. Could you test what is the value of

boost::is_convertible< const name_record::Ptr, const name_record

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::value

on your compiler?

No, this thing compiles and expands to false as expected. In fact, the error I'm getting is about

boost/boost/type_traits/is_convertible.hpp(254): error: class "name_record" has no suitable copy constructor BOOST_STATIC_CONSTANT(bool, value = ^ detected during: instantiation of class "boost::detail::is_convertible_basic_impl<From, To> [with From=boost::detail::is_convertible_impl<const name_record, const name_record>::ref_type, To=const name_record]" at line 286 instantiation of class "boost::detail::is_convertible_impl<From, To> [with From=const name_record, To=const name_record]" at line 362 instantiation of class "boost::detail::is_convertible_impl_dispatch<From, To> [with From=const name_record, To=const name_record]" at line 409 instantiation of class "boost::is_convertible<From, To> [with From=const name_record, To=const name_record]" at line 59 of "D:\src\3rd- parties\boost/boost/utility/enable_if.hpp"

and can be reproduced with

bool br = boost::is_convertible< const name_record, const name_record >::value;

It fails to compile as well. It seems that is_convertible doesn't handle noncopyable target type well.

I guess you mean the source type (i.e. the From argument.) Well, this also explains the problems you're getting, and it's a serious issue (IMHO) with boost::is_convertible. I'll report this in a separate post. In the meantime, I guess you can work around the problem by specializing boost::is_convertible<const name_record,const name_record> like this: namespace boost{ template<> struct is_convertible< const name_record, const name_record

: public true_type{};

} This tecnhique is sanctioned at http://boost.org/doc/html/boost_typetraits/user_defined.html HTH, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo