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<h1><img src="../../c++boost.gif" alt="c++boost.gif (8819 bytes)" align="center" width="277" height="86">Class
<a name="scoped_array">scoped_array</a></h1>
<p>Class <strong>scoped_array</strong> stores a pointer to a dynamically
allocated array. (Dynamically allocated arrays are allocated with the C++ <tt>new[]</tt>
expression.)&nbsp;&nbsp; The array pointed to is guaranteed to be deleted,
either on destruction of the <strong>scoped_array</strong>, or via an explicit <strong>scoped_array::reset()</strong>.</p>
<p>Class<strong> scoped_array</strong> is a simple solution for simple
needs.&nbsp; It cannot be used in C++ Standard Library containers.&nbsp; See <a href="shared_array.htm"><strong>shared_array</strong></a>
if <strong>scoped_array</strong> does not meet your needs.</p>
<p>Class<strong> scoped_array</strong> cannot correctly hold a pointer to a
single object.&nbsp; See <a href="scoped_ptr.htm"><strong>scoped_ptr</strong></a>
for that usage.</p>
<p>Because <strong>scoped_array</strong> is so simple, in its usual
implementation every operation is as fast as a built-in array pointer and has no
more space overhead that a built-in array pointer.</p>
<p>A heavier duty alternative to a <strong>scoped_array</strong> is a <strong>scoped_ptr</strong>
to a C++ Standard Library <strong>vector</strong>.</p>
<p>The class is a template parameterized on <tt>T</tt>, the type of the object
pointed to.&nbsp;&nbsp; <tt>T</tt> must meet the smart pointer <a href="smart_ptr.htm#Common requirements">common
requirements</a>.</p>
<h2>Class scoped_array Synopsis</h2>
<pre>#include &lt;boost/smart_ptr.hpp&gt;
namespace boost {
template&lt;typename T&gt; class scoped_array : <a href="../utility/utility.htm#noncopyable">noncopyable</a> {
public:
typedef T <a href="#scoped_array_element_type">element_type</a>;
explicit <a href="#scoped_array_ctor">scoped_array</a>( T* p=0 ); // never throws
<strong> </strong><a href="#scoped_array_~scoped_array">~scoped_array</a>();
void <a href="#scoped_array_reset">reset</a>( T* p=0 );
T&amp; <a href="#scoped_array_operator[]">operator[]</a>(std::size_t i) const; // never throws
T* <a href="#scoped_array_get">get</a>() const; // never throws
};
}</pre>
<h2>Class scoped_array Members</h2>
<h3>scoped_array <a name="scoped_array_element_type">element_type</a></h3>
<pre>typedef T element_type;</pre>
<p>Provides the type of the stored pointer.</p>
<h3><a name="scoped_array_ctor">scoped_array constructors</a></h3>
<pre>explicit scoped_array( T* p=0 ); // never throws</pre>
<p>Constructs a <tt>scoped_array</tt>, storing a copy of <tt>p</tt>, which must
have been allocated via a C++ <tt>new</tt>[] expression or be 0.</p>
<h3><a name="scoped_array_~scoped_array">scoped_array destructor</a></h3>
<pre>~scoped_array();</pre>
<p>Deletes the array 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_array <a name="scoped_array_reset">reset</a></h3>
<pre>void reset( T* p=0 )();</pre>
<p>If p is not equal to the stored pointer, deletes the array 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_array <a name="scoped_array_operator[]">operator[]</a></h3>
<p><tt>T&amp; operator[](std::size_t i) const; // never throws</tt></p>
<p>Returns a reference to element <tt>i</tt> of the array pointed to by the
stored pointer.</p>
<p>Behavior is undefined (and almost certainly undesirable) if <tt>get()==0</tt>,
or if <tt>i</tt> is less than 0 or is greater or equal to the number of elements
in the array.</p>
<h3>scoped_array <a name="scoped_array_get">get</a></h3>
<pre>T* get() const; // never throws</pre>
<p>Returns the stored pointer.</p>
<h2>Class <a name="shared_array_example">scoped_array example</a></h2>
<p>[To be supplied. In the meantime, see <a href="smart_ptr_test.cpp">smart_ptr_test.cpp</a>.]</p>
<hr>
<p>Revised&nbsp; December 8, 1999</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;
without express or implied warranty, and with no claim as to its suitability for
any purpose.</p>
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