1[/
2 / Copyright (c) 2003-2021 Christopher M. Kohlhoff (chris at kohlhoff dot com)
3 /
4 / Distributed under the Boost Software License, Version 1.0. (See accompanying
5 / file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6 /]
7
8[section:other_protocols Support for Other Protocols]
9
10Support for other socket protocols (such as Bluetooth or IRCOMM sockets) can be
11added by implementing the [link boost_asio.reference.Protocol protocol type
12requirements]. However, in many cases these protocols may also be used with
13Boost.Asio's generic protocol support. For this, Boost.Asio provides the following four
14classes:
15
16* [link boost_asio.reference.generic__datagram_protocol `generic::datagram_protocol`]
17* [link boost_asio.reference.generic__raw_protocol `generic::raw_protocol`]
18* [link boost_asio.reference.generic__seq_packet_protocol `generic::seq_packet_protocol`]
19* [link boost_asio.reference.generic__stream_protocol `generic::stream_protocol`]
20
21These classes implement the [link boost_asio.reference.Protocol protocol type
22requirements], but allow the user to specify the address family (e.g. `AF_INET`)
23and protocol type (e.g. `IPPROTO_TCP`) at runtime. For example:
24
25  boost::asio::generic::stream_protocol::socket my_socket(my_io_context);
26  my_socket.open(boost::asio::generic::stream_protocol(AF_INET, IPPROTO_TCP));
27  ...
28
29An endpoint class template, [link boost_asio.reference.generic__basic_endpoint
30`boost::asio::generic::basic_endpoint`], is included to support these protocol
31classes. This endpoint can hold any other endpoint type, provided its native
32representation fits into a `sockaddr_storage` object. This class will also
33convert from other types that implement the [link boost_asio.reference.Endpoint
34endpoint] type requirements:
35
36  boost::asio::ip::tcp::endpoint my_endpoint1 = ...;
37  boost::asio::generic::stream_protocol::endpoint my_endpoint2(my_endpoint1);
38
39The conversion is implicit, so as to support the following use cases:
40
41  boost::asio::generic::stream_protocol::socket my_socket(my_io_context);
42  boost::asio::ip::tcp::endpoint my_endpoint = ...;
43  my_socket.connect(my_endpoint);
44
45[heading C++11 Move Construction]
46
47When using C++11, it is possible to perform move construction from a socket (or
48acceptor) object to convert to the more generic protocol's socket (or acceptor)
49type. If the protocol conversion is valid:
50
51  Protocol1 p1 = ...;
52  Protocol2 p2(p1);
53
54then the corresponding socket conversion is allowed:
55
56  Protocol1::socket my_socket1(my_io_context);
57  ...
58  Protocol2::socket my_socket2(std::move(my_socket1));
59
60For example, one possible conversion is from a TCP socket to a generic
61stream-oriented socket:
62
63  boost::asio::ip::tcp::socket my_socket1(my_io_context);
64  ...
65  boost::asio::generic::stream_protocol::socket my_socket2(std::move(my_socket1));
66
67These conversions are also available for move-assignment.
68
69These conversions are not limited to the above generic protocol classes.
70User-defined protocols may take advantage of this feature by similarly ensuring
71the conversion from `Protocol1` to `Protocol2` is valid, as above.
72
73[heading Accepting Generic Sockets]
74
75As a convenience, a socket acceptor's `accept()` and `async_accept()` functions
76can directly accept into a different protocol's socket type, provided the
77corresponding protocol conversion is valid. For example, the following is
78supported because the protocol `boost::asio::ip::tcp` is convertible to
79`boost::asio::generic::stream_protocol`:
80
81  boost::asio::ip::tcp::acceptor my_acceptor(my_io_context);
82  ...
83  boost::asio::generic::stream_protocol::socket my_socket(my_io_context);
84  my_acceptor.accept(my_socket);
85
86[heading See Also]
87
88[link boost_asio.reference.generic__datagram_protocol `generic::datagram_protocol`],
89[link boost_asio.reference.generic__raw_protocol `generic::raw_protocol`],
90[link boost_asio.reference.generic__seq_packet_protocol `generic::seq_packet_protocol`],
91[link boost_asio.reference.generic__stream_protocol `generic::stream_protocol`],
92[link boost_asio.reference.Protocol protocol type requirements].
93
94[endsect]
95