detached.hpp
3.28 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
//
// detached.hpp
// ~~~~~~~~~~~~
//
// Copyright (c) 2003-2020 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// 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)
//
#ifndef ASIO_DETACHED_HPP
#define ASIO_DETACHED_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
#include "asio/detail/config.hpp"
#include <memory>
#include "asio/detail/type_traits.hpp"
#include "asio/detail/push_options.hpp"
namespace asio {
/// Class used to specify that an asynchronous operation is detached.
/**
* The detached_t class is used to indicate that an asynchronous operation is
* detached. That is, there is no completion handler waiting for the
* operation's result. A detached_t object may be passed as a handler to an
* asynchronous operation, typically using the special value
* @c asio::detached. For example:
* @code my_socket.async_send(my_buffer, asio::detached);
* @endcode
*/
class detached_t
{
public:
/// Constructor.
ASIO_CONSTEXPR detached_t()
{
}
/// Adapts an executor to add the @c detached_t completion token as the
/// default.
template <typename InnerExecutor>
struct executor_with_default : InnerExecutor
{
/// Specify @c detached_t as the default completion token type.
typedef detached_t default_completion_token_type;
/// Construct the adapted executor from the inner executor type.
executor_with_default(const InnerExecutor& ex) ASIO_NOEXCEPT
: InnerExecutor(ex)
{
}
/// Convert the specified executor to the inner executor type, then use
/// that to construct the adapted executor.
template <typename OtherExecutor>
executor_with_default(const OtherExecutor& ex,
typename enable_if<
is_convertible<OtherExecutor, InnerExecutor>::value
>::type* = 0) ASIO_NOEXCEPT
: InnerExecutor(ex)
{
}
};
/// Type alias to adapt an I/O object to use @c detached_t as its
/// default completion token type.
#if defined(ASIO_HAS_ALIAS_TEMPLATES) \
|| defined(GENERATING_DOCUMENTATION)
template <typename T>
using as_default_on_t = typename T::template rebind_executor<
executor_with_default<typename T::executor_type> >::other;
#endif // defined(ASIO_HAS_ALIAS_TEMPLATES)
// || defined(GENERATING_DOCUMENTATION)
/// Function helper to adapt an I/O object to use @c detached_t as its
/// default completion token type.
template <typename T>
static typename decay<T>::type::template rebind_executor<
executor_with_default<typename decay<T>::type::executor_type>
>::other
as_default_on(ASIO_MOVE_ARG(T) object)
{
return typename decay<T>::type::template rebind_executor<
executor_with_default<typename decay<T>::type::executor_type>
>::other(ASIO_MOVE_CAST(T)(object));
}
};
/// A special value, similar to std::nothrow.
/**
* See the documentation for asio::detached_t for a usage example.
*/
#if defined(ASIO_HAS_CONSTEXPR) || defined(GENERATING_DOCUMENTATION)
constexpr detached_t detached;
#elif defined(ASIO_MSVC)
__declspec(selectany) detached_t detached;
#endif
} // namespace asio
#include "asio/detail/pop_options.hpp"
#include "asio/impl/detached.hpp"
#endif // ASIO_DETACHED_HPP