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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. Distributed under the Boost Software License, Version
1.0. See accompanying file <A href="../../LICENSE_1_0.txt">LICENSE_1_0.txt</A> or
copy at <A href="http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</A>.</small></p>
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