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2 | Copyright 1999-2003 Beman Dawes | |
3 | Copyright 2014 Peter Dimov | |
4 | ||
5 | Distributed under the Boost Software License, Version 1.0. | |
6 | ||
7 | See accompanying file LICENSE_1_0.txt | |
8 | or copy at http://boost.org/LICENSE_1_0.txt | |
9 | ] | |
10 | ||
11 | [section:noncopyable noncopyable] | |
12 | ||
13 | [simplesect Authors] | |
14 | ||
15 | * Dave Abrahams | |
16 | ||
17 | [endsimplesect] | |
18 | ||
19 | [section Header <boost/core/noncopyable.hpp>] | |
20 | ||
21 | The header `<boost/noncopyable.hpp>` defines the class | |
22 | `boost::noncopyable`. It is intended to be used as a private | |
23 | base. `boost::noncopyable` has private (under C++03) or | |
24 | deleted (under C++11) copy constructor and a copy assignment | |
25 | operator and can't be copied or assigned; a class that derives | |
26 | from it inherits these properties. | |
27 | ||
28 | `boost::noncopyable` was originally contributed by Dave | |
29 | Abrahams. | |
30 | ||
31 | [section Synopsis] | |
32 | ||
33 | `` | |
34 | namespace boost | |
35 | { | |
36 | class noncopyable; | |
37 | } | |
38 | `` | |
39 | ||
40 | [endsect] | |
41 | ||
42 | [section Example] | |
43 | ||
44 | `` | |
45 | #include <boost/core/noncopyable.hpp> | |
46 | ||
47 | class X: private boost::noncopyable | |
48 | { | |
49 | }; | |
50 | `` | |
51 | ||
52 | [endsect] | |
53 | ||
54 | [section Rationale] | |
55 | ||
56 | Class noncopyable has protected constructor and destructor members to emphasize | |
57 | that it is to be used only as a base class. Dave Abrahams notes concern about | |
58 | the effect on compiler optimization of adding (even trivial inline) destructor | |
59 | declarations. He says: | |
60 | ||
61 | ["Probably this concern is misplaced, because `noncopyable` will be used mostly | |
62 | for classes which own resources and thus have non-trivial destruction semantics.] | |
63 | ||
64 | With C++2011, using an optimized and trivial constructor and similar destructor | |
65 | can be enforced by declaring both and marking them `default`. This is done in | |
66 | the current implementation. | |
67 | ||
68 | [endsect] | |
69 | ||
70 | [endsect] | |
71 | ||
72 | [endsect] |