Squashed 'third_party/boostorg/type_traits/' content from commit 059ed88
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+[/
+ Copyright 2007 John Maddock.
+ Distributed under the Boost Software License, Version 1.0.
+ (See accompanying file LICENSE_1_0.txt or copy at
+ http://www.boost.org/LICENSE_1_0.txt).
+]
+
+[section:is_abstract is_abstract]
+ template <class T>
+ struct is_abstract : public __tof {};
+
+__inherit If T is a (possibly cv-qualified) abstract type then inherits from
+__true_type, otherwise inherits from __false_type.
+
+__std_ref 10.3.
+
+__header ` #include <boost/type_traits/is_abstract.hpp>` or ` #include <boost/type_traits.hpp>`
+
+__compat The compiler must support DR337 (as of April 2005: GCC 3.4, VC++ 7.1 (and later),
+ Intel C++ 7 (and later), and Comeau 4.3.2).
+Otherwise behaves the same as __is_polymorphic;
+this is the "safe fallback position" for which polymorphic types are always
+regarded as potentially abstract. The macro BOOST_NO_IS_ABSTRACT is used to
+signify that the implementation is buggy, users should check for this in their
+own code if the "safe fallback" is not suitable for their particular use-case.
+
+__examples
+
+[:Given: `class abc{ virtual ~abc() = 0; };` ]
+
+[:`is_abstract<abc>` inherits from `__true_type`.]
+
+[:`is_abstract<abc>::type` is the type `__true_type`.]
+
+[:`is_abstract<abc const>::value` is an integral constant
+expression that evaluates to /true/.]
+
+[:`is_abstract<T>::value_type` is the type `bool`.]
+
+[endsect]
+