ceph/src/boost/boost/callable_traits/is_const_member.hpp

   1 /*
   2
   3 @Copyright Barrett Adair 2015-2017
   4 Distributed under the Boost Software License, Version 1.0.
   5 (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
   6
   7 */
   8
   9 #ifndef BOOST_CLBL_TRTS_IS_CONST_MEMBER_HPP
  10 #define BOOST_CLBL_TRTS_IS_CONST_MEMBER_HPP
  11
  12 #include <boost/callable_traits/detail/core.hpp>
  13
  14 namespace boost { namespace callable_traits {
  15
  16 //[ is_const_member_hpp
  17 /*`[section:ref_is_const_member is_const_member]
  18 [heading Header]
  19 ``#include <boost/callable_traits/is_const_member.hpp>``
  20 [heading Definition]
  21 */
  22
  23 // inherits from either std::true_type or std::false_type
  24 template<typename T>
  25 struct is_const_member;
  26
  27 //<-
  28 template<typename T>
  29 struct is_const_member
  30     : detail::traits<detail::shallow_decay<T>>::is_const_member {
  31     using type = typename detail::traits<
  32         detail::shallow_decay<T>>::is_const_member;
  33 };
  34
  35 #ifdef BOOST_CLBL_TRTS_DISABLE_VARIABLE_TEMPLATES
  36
  37 template<typename T>
  38 struct is_const_member_v {
  39     static_assert(std::is_same<T, detail::dummy>::value,
  40         "Variable templates not supported on this compiler.");
  41 };
  42
  43 #else
  44 //->
  45 // only available when variable templates are supported
  46 template<typename T>
  47 //<-
  48 BOOST_CLBL_TRAITS_INLINE_VAR
  49 //->
  50 constexpr bool is_const_member_v = //see below
  51 //<-
  52     detail::traits<detail::shallow_decay<T>>::is_const_member::value;
  53
  54 #endif
  55
  56 }} // namespace boost::callable_traits
  57 //->
  58
  59 /*`
  60 [heading Constraints]
  61 * none
  62
  63 [heading Behavior]
  64 * `is_const_member<T>::value` is `true` when either:
  65   * `T` is a function type with a `const` member qualifier
  66   * `T` is a pointer to a member function with a `const` member qualifier
  67   * `T` is a function object with a non-overloaded `operator()`, where the `operator()` has a `const` member qualifier
  68 * On compilers that support variable templates, `is_const_member_v<T>` is equivalent to `is_const_member<T>::value`.
  69
  70 [heading Input/Output Examples]
  71 [table
  72     [[`T`]                              [`is_const_member_v<T>`]]
  73     [[`int() const`]                    [`true`]]
  74     [[`int() const volatile`]           [`true`]]
  75     [[`int() const & transaction_safe`] [`true`]]
  76     [[`int() const &&`]                 [`true`]]
  77     [[`int(foo::*&)() const`]           [`true`]]
  78     [[`int(foo::*)() const volatile`]   [`true`]]
  79     [[`int(foo::*)() const volatile &&`][`true`]]
  80     [[`int(foo::* const)() const`]      [`true`]]
  81     [[`int()`]                          [`false`]]
  82     [[`int() volatile`]                 [`false`]]
  83     [[`int() &&`]                       [`false`]]
  84     [[`int(*)()`]                       [`false`]]
  85     [[`int`]                            [`false`]]
  86     [[`int foo::*`]                     [`false`]]
  87     [[`const int foo::*`]               [`false`]]
  88 ]
  89
  90 [heading Example Program]
  91 [import ../example/is_const_member.cpp]
  92 [is_const_member]
  93 [endsect]
  94 */
  95 //]
  96
  97 #endif // #ifndef BOOST_CLBL_TRTS_IS_CONST_MEMBER_HPP