1 //////////////////////////////////////////////////////////////////////////////
2 //
3 // (C) Copyright Ion Gaztanaga 2015-2015. Distributed under the Boost
4 // Software License, Version 1.0. (See accompanying file
5 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6 //
7 // See http://www.boost.org/libs/container for documentation.
8 //
9 //////////////////////////////////////////////////////////////////////////////
10 
11 #ifndef BOOST_CONTAINER_USES_ALLOCATOR_FWD_HPP
12 #define BOOST_CONTAINER_USES_ALLOCATOR_FWD_HPP
13 
14 #include <boost/container/detail/workaround.hpp>
15 #include <boost/container/detail/std_fwd.hpp>
16 
17 //! \file
18 //!   This header forward declares boost::container::constructible_with_allocator_prefix,
19 //!   boost::container::constructible_with_allocator_suffix and
20 //!   boost::container::uses_allocator. Also defines the following types:
21 
22 namespace boost {
23 namespace container {
24 
25 #ifndef BOOST_CONTAINER_DOXYGEN_INVOKED
26 
27    template <int Dummy = 0>
28    struct std_allocator_arg_holder
29    {
30       static ::std::allocator_arg_t *dummy;
31    };
32 
33    template <int Dummy>                                             //Silence null-reference compiler warnings
34    ::std::allocator_arg_t *std_allocator_arg_holder<Dummy>::dummy = reinterpret_cast< ::std::allocator_arg_t * >(0x1234);
35 
36 typedef const std::allocator_arg_t & allocator_arg_t;
37 
38 #else
39 
40 //! The allocator_arg_t struct is an empty structure type used as a unique type to
41 //! disambiguate constructor and function overloading. Specifically, several types
42 //! have constructors with allocator_arg_t as the first argument, immediately followed
43 //! by an argument of a type that satisfies Allocator requirements
44 typedef unspecified allocator_arg_t;
45 
46 #endif   //#ifndef BOOST_CONTAINER_DOXYGEN_INVOKED
47 
48 //! The `erased_type` struct is an empty struct that serves as a placeholder for a type
49 //! T in situations where the actual type T is determined at runtime. For example,
50 //! the nested type, `allocator_type`, is an alias for `erased_type` in classes that
51 //! use type-erased allocators.
52 struct erased_type {};
53 
54 //! A instance of type
55 //! allocator_arg_t
56 static allocator_arg_t allocator_arg = BOOST_CONTAINER_DOC1ST(unspecified, *std_allocator_arg_holder<>::dummy);
57 
58 // @cond
59 
60 template <class T>
61 struct constructible_with_allocator_suffix;
62 
63 template <class T>
64 struct constructible_with_allocator_prefix;
65 
66 template <typename T, typename Allocator>
67 struct uses_allocator;
68 
69 // @endcond
70 
71 }} // namespace boost { namespace container {
72 
73 #endif   //BOOST_CONTAINER_USES_ALLOCATOR_HPP
74