| Brian Silverman | 407d3cd | 2018-08-04 17:48:52 -0700 | [diff] [blame^] | 1 | [/ |
| 2 | / Copyright (c) 2002, 2003, 2005 Peter Dimov |
| 3 | / Copyright (c) 2014 Glen Fernandes |
| 4 | / |
| 5 | / Distributed under the Boost Software License, Version 1.0. (See |
| 6 | / accompanying file LICENSE_1_0.txt or copy at |
| 7 | / http://www.boost.org/LICENSE_1_0.txt) |
| 8 | /] |
| 9 | |
| 10 | [section:checked_delete checked_delete] |
| 11 | |
| 12 | [simplesect Authors] |
| 13 | |
| 14 | * Beman Dawes |
| 15 | * Dave Abrahams |
| 16 | * Vladimir Prus |
| 17 | * Rainer Deyke |
| 18 | * John Maddock |
| 19 | |
| 20 | [endsimplesect] |
| 21 | |
| 22 | [section Overview] |
| 23 | |
| 24 | The header `<boost/checked_delete.hpp>` defines two function |
| 25 | templates, `checked_delete` and `checked_array_delete`, and two |
| 26 | class templates, `checked_deleter` and `checked_array_deleter`. |
| 27 | |
| 28 | The C++ Standard allows, in 5.3.5/5, pointers to incomplete |
| 29 | class types to be deleted with a delete-expression. When the |
| 30 | class has a non-trivial destructor, or a class-specific |
| 31 | operator delete, the behavior is undefined. Some compilers |
| 32 | issue a warning when an incomplete type is deleted, but |
| 33 | unfortunately, not all do, and programmers sometimes ignore or |
| 34 | disable warnings. |
| 35 | |
| 36 | A particularly troublesome case is when a smart pointer's |
| 37 | destructor, such as `boost::scoped_ptr<T>::~scoped_ptr`, is |
| 38 | instantiated with an incomplete type. This can often lead to |
| 39 | silent, hard to track failures. |
| 40 | |
| 41 | The supplied function and class templates can be used to |
| 42 | prevent these problems, as they require a complete type, and |
| 43 | cause a compilation error otherwise. |
| 44 | |
| 45 | [endsect] |
| 46 | |
| 47 | [section Synopsis] |
| 48 | |
| 49 | `` |
| 50 | namespace boost |
| 51 | { |
| 52 | template<class T> void checked_delete(T * p); |
| 53 | template<class T> void checked_array_delete(T * p); |
| 54 | template<class T> struct checked_deleter; |
| 55 | template<class T> struct checked_array_deleter; |
| 56 | } |
| 57 | `` |
| 58 | |
| 59 | [endsect] |
| 60 | |
| 61 | [section checked_delete] |
| 62 | |
| 63 | [section template<class T> void checked_delete(T * p);] |
| 64 | |
| 65 | * *Requires:* `T` must be a complete type. The expression |
| 66 | `delete p` must be well-formed. |
| 67 | * *Effects:* `delete p;` |
| 68 | |
| 69 | [endsect] |
| 70 | |
| 71 | [endsect] |
| 72 | |
| 73 | [section checked_array_delete] |
| 74 | |
| 75 | [section template<class T> void checked_array_delete(T * p);] |
| 76 | |
| 77 | * *Requires:* `T` must be a complete type. The expression |
| 78 | `delete [] p` must be well-formed. |
| 79 | * *Effects:* `delete [] p;` |
| 80 | |
| 81 | [endsect] |
| 82 | |
| 83 | [endsect] |
| 84 | |
| 85 | [section checked_deleter] |
| 86 | |
| 87 | `` |
| 88 | template<class T> struct checked_deleter |
| 89 | { |
| 90 | typedef void result_type; |
| 91 | typedef T * argument_type; |
| 92 | void operator()(T * p) const; |
| 93 | }; |
| 94 | `` |
| 95 | |
| 96 | [section void checked_deleter<T>::operator()(T * p) const;] |
| 97 | |
| 98 | * *Requires:* `T` must be a complete type. The expression |
| 99 | `delete p` must be well-formed. |
| 100 | * *Effects:* `delete p;` |
| 101 | |
| 102 | [endsect] |
| 103 | |
| 104 | [endsect] |
| 105 | |
| 106 | [section checked_array_deleter] |
| 107 | |
| 108 | `` |
| 109 | template<class T> struct checked_array_deleter |
| 110 | { |
| 111 | typedef void result_type; |
| 112 | typedef T * argument_type; |
| 113 | void operator()(T * p) const; |
| 114 | }; |
| 115 | `` |
| 116 | |
| 117 | [section void checked_array_deleter<T>::operator()(T * p) const;] |
| 118 | |
| 119 | * *Requires:* `T` must be a complete type. The expression |
| 120 | `delete [] p` must be well-formed. |
| 121 | * *Effects:* `delete [] p;` |
| 122 | |
| 123 | [endsect] |
| 124 | |
| 125 | [endsect] |
| 126 | |
| 127 | [section Acknowledgements] |
| 128 | |
| 129 | The function templates `checked_delete` and |
| 130 | `checked_array_delete` were originally part of |
| 131 | `<boost/utility.hpp>`, and the documentation |
| 132 | acknowledged Beman Dawes, Dave Abrahams, |
| 133 | Vladimir Prus, Rainer Deyke, John Maddock, |
| 134 | and others as contributors. |
| 135 | |
| 136 | [endsect] |
| 137 | |
| 138 | [endsect] |