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<h1>checked_delete.hpp</h1>
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<p>
The header <STRONG><boost/checked_delete.hpp></STRONG> defines two
function templates, <STRONG>checked_delete</STRONG> and <STRONG>checked_array_delete</STRONG>,
and two class templates, <STRONG>checked_deleter</STRONG> and <STRONG>checked_array_deleter</STRONG>.
</p>
<P>The C++ Standard allows, in 5.3.5/5, pointers to incomplete class types to be
deleted with a <EM>delete-expression</EM>. 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.</P>
<P>A particularly troublesome case is when a smart pointer's destructor, such as <STRONG>
boost::scoped_ptr<T>::~scoped_ptr</STRONG>, is instantiated with an
incomplete type. This can often lead to silent, hard to track failures.</P>
<P>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.</P>
<h3><a name="Synopsis">Synopsis</a></h3>
<pre>
namespace boost
{
template<class T> void checked_delete(T * p);
template<class T> void checked_array_delete(T * p);
template<class T> struct checked_deleter;
template<class T> struct checked_array_deleter;
}
</pre>
<h3>checked_delete</h3>
<h4><a name="checked_delete">template<class T> void checked_delete(T * p);</a></h4>
<blockquote>
<p>
<b>Requires:</b> <b>T</b> must be a complete type. The expression <tt>delete p</tt>
must be well-formed.
</p>
<p>
<b>Effects:</b> <tt>delete p;</tt>
</p>
</blockquote>
<h3>checked_array_delete</h3>
<h4><a name="checked_array_delete">template<class T> void checked_array_delete(T
* p);</a></h4>
<blockquote>
<p>
<b>Requires:</b> <b>T</b> must be a complete type. The expression <tt>delete [] p</tt>
must be well-formed.
</p>
<p>
<b>Effects:</b> <tt>delete [] p;</tt>
</p>
</blockquote>
<h3>checked_deleter</h3>
<pre>
template<class T> struct checked_deleter
{
typedef void result_type;
typedef T * argument_type;
void operator()(T * p) const;
};
</pre>
<h4>void checked_deleter<T>::operator()(T * p) const;</h4>
<blockquote>
<p>
<b>Requires:</b> <b>T</b> must be a complete type. The expression <tt>delete p</tt>
must be well-formed.
</p>
<p>
<b>Effects:</b> <tt>delete p;</tt>
</p>
</blockquote>
<h3>checked_array_deleter</h3>
<pre>
template<class T> struct checked_array_deleter
{
typedef void result_type;
typedef T * argument_type;
void operator()(T * p) const;
};
</pre>
<h4>void checked_array_deleter<T>::operator()(T * p) const;</h4>
<blockquote>
<p>
<b>Requires:</b> <b>T</b> must be a complete type. The expression <tt>delete [] p</tt>
must be well-formed.
</p>
<p>
<b>Effects:</b> <tt>delete [] p;</tt>
</p>
</blockquote>
<h3><a name="Acknowledgements">Acknowledgements</a></h3>
<p>
The function templates <STRONG>checked_delete</STRONG> and <STRONG>checked_array_delete</STRONG>
were originally part of <STRONG><boost/utility.hpp></STRONG>, and the
documentation acknowledged Beman Dawes, Dave Abrahams, Vladimir Prus, Rainer
Deyke, John Maddock, and others as contributors.
</p>
<p>
<br>
<small>Copyright 2002 by Peter Dimov. Permission to copy, use, modify, sell and
distribute this document is granted provided this copyright notice appears in
all copies. This document is provided "as is" without express or implied
warranty, and with no claim as to its suitability for any purpose.</small></p>
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