2002-11-14 14:53:32 +00:00
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<title>Boost: checked_delete.hpp documentation</title>
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2004-10-05 15:45:52 +00:00
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<h1>checked_delete.hpp</h1>
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<p>
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The header <STRONG><boost/checked_delete.hpp></STRONG> defines two
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function templates, <STRONG>checked_delete</STRONG> and <STRONG>checked_array_delete</STRONG>,
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and two class templates, <STRONG>checked_deleter</STRONG> and <STRONG>checked_array_deleter</STRONG>.
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</p>
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2003-02-14 16:20:01 +00:00
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<P>The C++ Standard allows, in 5.3.5/5, pointers to incomplete class types to be
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deleted with a <EM>delete-expression</EM>. When the class has a non-trivial
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destructor, or a class-specific operator delete, the behavior is undefined.
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Some compilers issue a warning when an incomplete type is deleted, but
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unfortunately, not all do, and programmers sometimes ignore or disable
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warnings.</P>
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<P>A particularly troublesome case is when a smart pointer's destructor, such as <STRONG>
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boost::scoped_ptr<T>::~scoped_ptr</STRONG>, is instantiated with an
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incomplete type. This can often lead to silent, hard to track failures.</P>
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<P>The supplied function and class templates can be used to prevent these problems,
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as they require a complete type, and cause a compilation error otherwise.</P>
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<h3><a name="Synopsis">Synopsis</a></h3>
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<pre>
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namespace boost
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{
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template<class T> void checked_delete(T * p);
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template<class T> void checked_array_delete(T * p);
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template<class T> struct checked_deleter;
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template<class T> struct checked_array_deleter;
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}
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</pre>
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<h3>checked_delete</h3>
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<h4><a name="checked_delete">template<class T> void checked_delete(T * p);</a></h4>
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<blockquote>
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<p>
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<b>Requires:</b> <b>T</b> must be a complete type. The expression <tt>delete p</tt>
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must be well-formed.
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</p>
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<p>
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<b>Effects:</b> <tt>delete p;</tt>
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</p>
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</blockquote>
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<h3>checked_array_delete</h3>
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<h4><a name="checked_array_delete">template<class T> void checked_array_delete(T
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* p);</a></h4>
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<blockquote>
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<p>
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<b>Requires:</b> <b>T</b> must be a complete type. The expression <tt>delete [] p</tt>
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must be well-formed.
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</p>
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<p>
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<b>Effects:</b> <tt>delete [] p;</tt>
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</p>
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</blockquote>
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<h3>checked_deleter</h3>
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<pre>
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template<class T> struct checked_deleter
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{
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typedef void result_type;
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typedef T * argument_type;
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void operator()(T * p) const;
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};
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</pre>
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<h4>void checked_deleter<T>::operator()(T * p) const;</h4>
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<blockquote>
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<p>
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<b>Requires:</b> <b>T</b> must be a complete type. The expression <tt>delete p</tt>
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must be well-formed.
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</p>
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<p>
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<b>Effects:</b> <tt>delete p;</tt>
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</p>
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</blockquote>
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<h3>checked_array_deleter</h3>
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<pre>
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template<class T> struct checked_array_deleter
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{
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typedef void result_type;
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typedef T * argument_type;
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void operator()(T * p) const;
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};
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</pre>
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<h4>void checked_array_deleter<T>::operator()(T * p) const;</h4>
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2002-11-14 14:53:32 +00:00
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<blockquote>
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<p>
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<b>Requires:</b> <b>T</b> must be a complete type. The expression <tt>delete [] p</tt>
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must be well-formed.
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</p>
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<p>
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<b>Effects:</b> <tt>delete [] p;</tt>
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</p>
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</blockquote>
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<h3><a name="Acknowledgements">Acknowledgements</a></h3>
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<p>
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The function templates <STRONG>checked_delete</STRONG> and <STRONG>checked_array_delete</STRONG>
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were originally part of <STRONG><boost/utility.hpp></STRONG>, and the
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documentation acknowledged Beman Dawes, Dave Abrahams, Vladimir Prus, Rainer
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Deyke, John Maddock, and others as contributors.
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2002-11-14 14:53:32 +00:00
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</p>
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<p>
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<br>
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2003-02-14 16:20:01 +00:00
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<small>Copyright <20> 2002 by Peter Dimov. Permission to copy, use, modify, sell and
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distribute this document is granted provided this copyright notice appears in
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all copies. This document is provided "as is" without express or implied
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warranty, and with no claim as to its suitability for any purpose.</small></p>
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