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Smart pointer and utility changes related to adding checked_delere and checked_array_delete

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[SVN r10189]
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Beman Dawes
2001-05-22 18:58:21 +00:00
parent ac8d0f5505
commit a90a157ea6
9 changed files with 167 additions and 41 deletions
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scoped_ptr.htm
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@@ -59,25 +59,38 @@ template&lt;typename T&gt; class scoped_ptr : <a href="../utility/utility.htm#cl
<p>Provides the type of the stored pointer.</p>
<h3><a name="scoped_ptr_ctor">scoped_ptr constructors</a></h3>
<pre>explicit scoped_ptr( T* p=0 ); // never throws</pre>
<p><b>T</b> is not required be a complete type at point of instantiation.&nbsp;
See <a href="smart_ptr.htm#Common requirements">Common Requirements</a>.</p>
<p>Constructs a <tt>scoped_ptr</tt>, storing a copy of <tt>p</tt>, which must
have been allocated via a C++ <tt>new</tt> expression or be 0..</p>
have been allocated via a C++ <tt>new</tt> expression or be 0.</p>
<h3><a name="scoped_ptr_~scoped_ptr">scoped_ptr destructor</a></h3>
<pre>~scoped_ptr();</pre>
<p><b>T</b> is required be a complete type at point of instantiation.&nbsp; See <a href="smart_ptr.htm#Common requirements">Common
Requirements</a>.</p>
<p>Deletes the object pointed to by the stored pointer.&nbsp; Note that in C++, <tt>delete</tt>
on a pointer with a value of 0 is harmless.</p>
<p>Does not throw exceptions.</p>
<h3>scoped_ptr <a name="scoped_ptr_reset">reset</a></h3>
<pre>void reset( T* p=0 );</pre>
<p><b>T</b> is required be a complete type at point of instantiation.&nbsp; See <a href="smart_ptr.htm#Common requirements">Common
Requirements</a>.</p>
<p>If p is not equal to the stored pointer, deletes the object pointed to by the
stored pointer and then stores a copy of p, which must have been allocated via a
C++ <tt>new</tt> expression or be 0.</p>
<p>Does not throw exceptions.</p>
<h3>scoped_ptr <a name="scoped_ptr_operator*">operator*</a></h3>
<pre>T&amp; operator*() const; // never throws</pre>
<p><b>T</b> is required be a complete type at point of instantiation.&nbsp; See <a href="smart_ptr.htm#Common requirements">Common
Requirements</a>.</p>
<p>Returns a reference to the object pointed to by the stored pointer.</p>
<h3>scoped_ptr <a name="scoped_ptr_operator-&gt;">operator-&gt;</a> and <a name="scoped_ptr_get">get</a></h3>
<pre>T* operator-&gt;() const; // never throws
T* get() const; // never throws</pre>
<p><b>T</b> is required be a complete type at point of instantiation of
operator-&gt;().&nbsp; See <a href="smart_ptr.htm#Common requirements">Common
Requirements</a>.</p>
<p><b>T</b> is not required be a complete type at point of instantiation of
get().&nbsp; See <a href="smart_ptr.htm#Common requirements">Common Requirements</a>.</p>
<p>Both return the stored pointer.</p>
<h2>Class <a name="scoped_ptr_example">scoped_ptr example</a>s</h2>
<pre>#include &lt;iostream&gt;
@@ -106,24 +119,16 @@ output:</p>
Buckle my shoe</pre>
</blockquote>
<h2>Handle/Body Idiom</h2>
<p>One common usage of <b>scoped_ptr</b> is to implement a handle/body
structure which avoids exposing the body (implementation) in the header file:</p>
<pre>class handle
{
public: // simple forwarding functions to the body class
void f();
void g(int);
private:
friend class body; //incomplete class hides implementation
boost::scoped_ptr&lt;body&gt; imp;
};</pre>
<p>This code requires that <code>class body</code> have a trivial destructor to
avoid undefined behavior.&nbsp; This is because the definition of <code>class
body</code> is not visible at the time scoped_ptr&lt;&gt; deletes it. See ISO
5.3.5/5.&nbsp; Note that some compilers will issue a warning even though the
above code is well defined.</p>
<p>One common usage of <b>scoped_ptr</b> is to implement a handle/body idiom which avoids exposing the body (implementation) in the header
file.</p>
<p>The <a href="scoped_ptr_example_test.cpp">scoped_ptr_example_test.cpp</a>
sample program includes a header file, <a href="scoped_ptr_example.hpp">scoped_ptr_example.hpp</a>,
which uses a <b>scoped_ptr&lt;&gt;</b> to an incomplete type to hide the
implementation.&nbsp;&nbsp; The
instantiation of member functions which require a complete type occurs in the <a href="scoped_ptr_example.cpp">scoped_ptr_example.cpp</a>
implementation file.&nbsp;</p>
<hr>
<p>Revised <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %B %Y" startspan -->21 May 2001<!--webbot bot="Timestamp" endspan i-checksum="15104" --></p>
<p>Revised <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %B %Y" startspan -->22 May 2001<!--webbot bot="Timestamp" endspan i-checksum="15106" --></p>
<p><EFBFBD> Copyright Greg Colvin and Beman Dawes 1999. Permission to copy, use,
modify, sell and distribute this document is granted provided this copyright
notice appears in all copies. This document is provided &quot;as is&quot;