From 0db9276e8c635c3d935287cb97accd94ed7ecd6c Mon Sep 17 00:00:00 2001 From: Daryle Walker Date: Fri, 17 Feb 2012 01:55:33 +0000 Subject: [PATCH] Fixed (hopefully) conflict between boost::base_from_member's C++11 constructor template and the automatically defined non-template copy- and/or move-constructors. [SVN r77046] --- base_from_member.html | 24 ++++---- include/boost/utility/base_from_member.hpp | 64 +++++++++++++++++++++- 2 files changed, 75 insertions(+), 13 deletions(-) diff --git a/base_from_member.html b/base_from_member.html index df4add2..07e144e 100644 --- a/base_from_member.html +++ b/base_from_member.html @@ -174,16 +174,18 @@ value of zero if it is omitted. The class template has a protected data member called member that the derived class can use for later base classes (or itself).

-

If the variadic template arguments and r-value reference features of C++2011 -are present, there will be a single constructor template. It implements -"perfect forwarding" to the best constructor call of -member (if any). The constructor template is marked both -constexpr and explicit. The former will be ignored -if the corresponding inner constructor call (of member) does not -have the marker. The latter binds the other way; always taking effect, even -when the inner constructor call does not have the marker. The constructor -template propagates the noexcept status of the inner constructor -call.

+

If the appropriate features of C++2011 are present, there will be a single +constructor template. It implements "perfect forwarding" to the best +constructor call of member (if any). The constructor template is +marked both constexpr and explicit. The former will +be ignored if the corresponding inner constructor call (of member) +does not have the marker. The latter binds the other way; always taking +effect, even when the inner constructor call does not have the marker. The +constructor template propagates the noexcept status of the inner +constructor call. (The constructor template has a trailing parameter with a +default value that disables the template when its signature is too close to the +signatures of the automatically-defined non-template copy- and/or +move-constructors of base_from_member.)

On earlier-standard compilers, there is a default constructor and several constructor member templates. These constructor templates can take as many @@ -385,7 +387,7 @@ a constructor call but std::nullptr_t cannot.)

-

Revised: 11 February 2012

+

Revised: 16 February 2012

Copyright 2001, 2003, 2004, 2012 Daryle Walker. Use, modification, and distribution are subject to the Boost Software License, Version 1.0. (See accompanying diff --git a/include/boost/utility/base_from_member.hpp b/include/boost/utility/base_from_member.hpp index 8148077..8d17522 100644 --- a/include/boost/utility/base_from_member.hpp +++ b/include/boost/utility/base_from_member.hpp @@ -15,6 +15,10 @@ #include #include #include +#include +#include +#include +#include // Base-from-member arity configuration macro ------------------------------// @@ -54,6 +58,59 @@ namespace boost { +namespace detail +{ + +// Type-unmarking class template -------------------------------------------// + +// Type-trait to get the raw type, i.e. the type without top-level reference nor +// cv-qualification, from a type expression. Mainly for function arguments, any +// reference part is stripped first. + +// Contributed by Daryle Walker + +template < typename T > +struct remove_cv_ref +{ + typedef typename ::boost::remove_cv::type>::type type; + +}; // boost::detail::remove_cv_ref + +// Unmarked-type comparison class template ---------------------------------// + +// Type-trait to check if two type expressions have the same raw type. + +// Contributed by Daryle Walker, based on a work-around by Luc Danton + +template < typename T, typename U > +struct is_related + : public ::boost::is_same< + typename ::boost::detail::remove_cv_ref::type, + typename ::boost::detail::remove_cv_ref::type > +{}; + +// Enable-if-on-unidentical-unmarked-type class template -------------------// + +// Enable-if on the first two type expressions NOT having the same raw type. + +// Contributed by Daryle Walker, based on a work-around by Luc Danton + +#ifndef BOOST_NO_VARIADIC_TEMPLATES +template +struct enable_if_unrelated + : public ::boost::enable_if_c +{}; + +template +struct enable_if_unrelated + : public ::boost::disable_if< ::boost::detail::is_related > +{}; +#endif + +} // namespace boost::detail + + // Base-from-member class template -----------------------------------------// // Helper to initialize a base object so a derived class can use this @@ -69,8 +126,11 @@ class base_from_member protected: MemberType member; -#if defined(BOOST_HAS_RVALUE_REFS) && defined(BOOST_HAS_VARIADIC_TMPL) - template +#if !defined(BOOST_NO_RVALUE_REFERENCES) && \ + !defined(BOOST_NO_VARIADIC_TEMPLATES) && \ + !defined(BOOST_NO_FUNCTION_TEMPLATE_DEFAULT_ARGS) + template ::type> explicit BOOST_CONSTEXPR base_from_member( T&& ...x ) BOOST_NOEXCEPT_IF( BOOST_NOEXCEPT_EXPR(::new ((void*) 0) MemberType( static_cast(x)... )) ) // no std::is_nothrow_constructible...