#ifndef BOOST_CHECKED_DELETE_HPP_INCLUDED2
#define BOOST_CHECKED_DELETE_HPP_INCLUDED3
4
// MS compatible compilers support #pragma once5
6
#if defined(_MSC_VER) && (_MSC_VER >= 1020)7
# pragma once8
#endif9
10
//11
// boost/checked_delete.hpp12
//13
// Copyright (c) 2002, 2003 Peter Dimov14
// Copyright (c) 2003 Daniel Frey15
// Copyright (c) 2003 Howard Hinnant16
//17
// Distributed under the Boost Software License, Version 1.0. (See18
// accompanying file LICENSE_1_0.txt or copy at19
// http://www.boost.org/LICENSE_1_0.txt)20
//21
// See http://www.boost.org/libs/utility/checked_delete.html for documentation.22
//23
24
namespace boost25
{26
27
// verify that types are complete for increased safety28
29
template<class T> inline void checked_delete(T * x)30
{31
// intentionally complex - simplification causes regressions32
typedef char type_must_be_complete[ sizeof(T)? 1: -1 ];33
(void) sizeof(type_must_be_complete);34
delete x;35
}36
37
template<class T> inline void checked_array_delete(T * x)38
{39
typedef char type_must_be_complete[ sizeof(T)? 1: -1 ];40
(void) sizeof(type_must_be_complete);41
delete [] x;42
}43
44
template<class T> struct checked_deleter45
{46
typedef void result_type;47
typedef T * argument_type;48
49
void operator()(T * x) const50
{51
// boost:: disables ADL52
boost::checked_delete(x);53
}54
};55
56
template<class T> struct checked_array_deleter57
{58
typedef void result_type;59
typedef T * argument_type;60
61
void operator()(T * x) const62
{63
boost::checked_array_delete(x);64
}65
};66
67
} // namespace boost68
69
#endif // #ifndef BOOST_CHECKED_DELETE_HPP_INCLUDED
------------------------------------
source錛?a >http://www.boost.org/doc/libs/1_39_0/libs/utility/checked_delete.html
The header <boost/checked_delete.hpp> defines two function templates, checked_delete and checked_array_delete, and two class templates, checked_deleter and checked_array_deleter.
The C++ Standard allows, in 5.3.5/5, pointers to incomplete class types to be deleted with a delete-expression. When the class has a non-trivial destructor, or a class-specific operator delete, the behavior is undefined. Some compilers issue a warning when an incomplete type is deleted, but unfortunately, not all do, and programmers sometimes ignore or disable warnings.
A particularly troublesome case is when a smart pointer's destructor, such as boost::scoped_ptr<T>::~scoped_ptr, is instantiated with an incomplete type. This can often lead to silent, hard to track failures.
The supplied function and class templates can be used to prevent these problems, as they require a complete type, and cause a compilation error otherwise.
Synopsis
namespace boost2
{3
4
template<class T> void checked_delete(T * p);5
template<class T> void checked_array_delete(T * p);6
template<class T> struct checked_deleter;7
template<class T> struct checked_array_deleter;8
9
}10
11
checked_delete12
template<class T> void checked_delete(T * p);13
14
Requires: T must be a complete type. The expression delete p must be well-formed.
Effects: delete p;
checked_array_delete2
template<class T> void checked_array_delete(T * p);3
Requires: T must be a complete type. The expression delete [] p must be well-formed. 4
5
Effects: delete [] p; 6
7
checked_deleter8
template<class T> struct checked_deleter9
{10
typedef void result_type;11
typedef T * argument_type;12
void operator()(T * p) const;13
};14
15
void checked_deleter<T>::operator()(T * p) const;16
17
Requires: T must be a complete type. The expression delete p must be well-formed.
Effects: delete p;
checked_array_deleter2
template<class T> struct checked_array_deleter3
{4
typedef void result_type;5
typedef T * argument_type;6
void operator()(T * p) const;7
};8
9
void checked_array_deleter<T>::operator()(T * p) const;10
Requires: T must be a complete type. The expression delete [] p must be well-formed.
Effects: delete [] p;
Acknowledgements
The function templates checked_delete and checked_array_delete were originally part of <boost/utility.hpp>, and the documentation acknowledged Beman Dawes, Dave Abrahams, Vladimir Prus, Rainer Deyke, John Maddock, and others as contributors.
Copyright © 2002 by Peter Dimov. 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.
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