]>
Commit | Line | Data |
---|---|---|
7c673cae FG |
1 | [/ |
2 | Copyright 2007 John Maddock. | |
3 | Distributed under the Boost Software License, Version 1.0. | |
4 | (See accompanying file LICENSE_1_0.txt or copy at | |
5 | http://www.boost.org/LICENSE_1_0.txt). | |
6 | ] | |
7 | ||
8 | [section:is_pointer is_pointer] | |
9 | template <class T> | |
10 | struct is_pointer : public __tof {}; | |
11 | ||
12 | __inherit If T is a (possibly cv-qualified) pointer type (includes function pointers, | |
13 | but excludes pointers to members) then inherits from __true_type, | |
14 | otherwise inherits from __false_type. | |
15 | ||
16 | __std_ref 3.9.2p2 and 8.3.1. | |
17 | ||
18 | __header ` #include <boost/type_traits/is_pointer.hpp>` or ` #include <boost/type_traits.hpp>` | |
19 | ||
20 | [all_compilers] | |
21 | ||
22 | __examples | |
23 | ||
24 | [:`is_pointer<int*>` inherits from `__true_type`.] | |
25 | ||
26 | [:`is_pointer<char* const>::type` is the type `__true_type`.] | |
27 | ||
28 | [:`is_pointer<int (*)(long)>::value` is an integral constant | |
29 | expression that evaluates to /true/.] | |
30 | ||
31 | [:`is_pointer<int (MyClass::*)(long)>::value` is an integral constant | |
32 | expression that evaluates to /false/.] | |
33 | ||
34 | [:`is_pointer<int (MyClass::*)>::value` is an integral constant | |
35 | expression that evaluates to /false/.] | |
36 | ||
37 | [:`is_pointer<T>::value_type` is the type `bool`.] | |
38 | ||
39 | [important `is_pointer` detects "real" pointer types only, and /not/ smart pointers. | |
40 | Users should not specialise `is_pointer` for smart pointer types, as doing so may cause | |
41 | Boost (and other third party) code to fail to function correctly. | |
42 | Users wanting a trait to detect smart pointers should create their own. | |
43 | However, note that there is no way in general to auto-magically detect smart pointer types, | |
44 | so such a trait would have to be partially specialised for each supported smart pointer type.] | |
45 | ||
46 | [endsect] | |
47 |