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<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="default_delete.html" title="cpp/memory/default delete"><span class="t-lines"><span>default_delete</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv-h1"><td colspan="5"> Allocators</td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><strong class="selflink"><span class="t-lines"><span>allocator</span></span></strong></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator_traits.html" title="cpp/memory/allocator traits"><span class="t-lines"><span>allocator_traits</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator_arg_t.html" title="cpp/memory/allocator arg t"><span class="t-lines"><span>allocator_arg_t</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator_arg.html" title="cpp/memory/allocator arg"><span class="t-lines"><span>allocator_arg</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="uses_allocator.html" title="cpp/memory/uses allocator"><span class="t-lines"><span>uses_allocator</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="scoped_allocator_adaptor.html" title="cpp/memory/scoped allocator adaptor"><span class="t-lines"><span>scoped_allocator_adaptor</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv-h1"><td colspan="5"> Uninitialized storage</td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="uninitialized_copy.html" title="cpp/memory/uninitialized copy"><span class="t-lines"><span>uninitialized_copy</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="uninitialized_copy_n.html" title="cpp/memory/uninitialized copy n"><span class="t-lines"><span>uninitialized_copy_n</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="uninitialized_fill.html" title="cpp/memory/uninitialized fill"><span class="t-lines"><span>uninitialized_fill</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="uninitialized_fill_n.html" title="cpp/memory/uninitialized fill n"><span class="t-lines"><span>uninitialized_fill_n</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="raw_storage_iterator.html" title="cpp/memory/raw storage iterator"><span class="t-lines"><span>raw_storage_iterator</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="get_temporary_buffer.html" title="cpp/memory/get temporary buffer"><span class="t-lines"><span>get_temporary_buffer</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="return_temporary_buffer.html" title="cpp/memory/return temporary buffer"><span class="t-lines"><span>return_temporary_buffer</span></span></a></div></div></td></tr>
<tr class="t-nv-h1"><td colspan="5"> Garbage collection support</td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="gc/declare_reachable.html" title="cpp/memory/gc/declare reachable"><span class="t-lines"><span>declare_reachable</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="gc/undeclare_reachable.html" title="cpp/memory/gc/undeclare reachable"><span class="t-lines"><span>undeclare_reachable</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="gc/declare_no_pointers.html" title="cpp/memory/gc/declare no pointers"><span class="t-lines"><span>declare_no_pointers</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="gc/undeclare_no_pointers.html" title="cpp/memory/gc/undeclare no pointers"><span class="t-lines"><span>undeclare_no_pointers</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="gc/pointer_safety.html" title="cpp/memory/gc/pointer safety"><span class="t-lines"><span>pointer_safety</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="gc/get_pointer_safety.html" title="cpp/memory/gc/get pointer safety"><span class="t-lines"><span>get_pointer_safety</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv-h1"><td colspan="5"> Miscellaneous</td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="pointer_traits.html" title="cpp/memory/pointer traits"><span class="t-lines"><span>pointer_traits</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="addressof.html" title="cpp/memory/addressof"><span class="t-lines"><span>addressof</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="align.html" title="cpp/memory/align"><span class="t-lines"><span>align</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv-h1"><td colspan="5"> <a href="c.html" title="cpp/memory/c">C Library</a></td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="c/malloc.html" title="cpp/memory/c/malloc"><span class="t-lines"><span>malloc</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="c/calloc.html" title="cpp/memory/c/calloc"><span class="t-lines"><span>calloc</span></span></a></div></div></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="c/realloc.html" title="cpp/memory/c/realloc"><span class="t-lines"><span>realloc</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="c/free.html" title="cpp/memory/c/free"><span class="t-lines"><span>free</span></span></a></div></div></td></tr>
</table></div></td></tr>
<tr class="t-nv-h1"><td colspan="5"> <a href="new.1.html" title="cpp/memory/new">Low level memory management</a></td></tr>
</table></div><div><span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/memory/navbar_content&action=edit">[edit]</a></span></div></div></div></div><div class="t-navbar-sep"> </div><div class="t-navbar-head"><strong class="selflink"><tt>std::allocator</tt></strong><div class="t-navbar-menu"><div><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv-h1"><td colspan="5"> Member functions</td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator/allocator.html" title="cpp/memory/allocator/allocator"><span class="t-lines"><span>allocator::allocator</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator/~allocator.html" title="cpp/memory/allocator/~allocator"><span class="t-lines"><span>allocator::~allocator</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator/address.html" title="cpp/memory/allocator/address"><span class="t-lines"><span>allocator::address</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator/allocate.html" title="cpp/memory/allocator/allocate"><span class="t-lines"><span>allocator::allocate</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator/deallocate.html" title="cpp/memory/allocator/deallocate"><span class="t-lines"><span>allocator::deallocate</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator/max_size.html" title="cpp/memory/allocator/max size"><span class="t-lines"><span>allocator::max_size</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator/construct.html" title="cpp/memory/allocator/construct"><span class="t-lines"><span>allocator::construct</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator/destroy.html" title="cpp/memory/allocator/destroy"><span class="t-lines"><span>allocator::destroy</span></span></a></div></div></td></tr>
<tr class="t-nv-h1"><td colspan="5"> Non-member functions</td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator/operator_cmp.html" title="cpp/memory/allocator/operator cmp"><span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div></div></td></tr>
</table></div><div><span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/memory/allocator/navbar_content&action=edit">[edit]</a></span></div></div></div></div><div class="t-navbar-sep"> </div></div>
<table class="t-dcl-begin"><tbody>
<tr class="t-dsc-header">
<td> <div>Defined in header <code><a href="../header/memory.html" title="cpp/header/memory"><memory></a></code>
</div></td>
<td></td>
<td></td>
</tr>
<tr class="t-dcl">
<td> <div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span> <span class="kw1">class</span> T <span class="sy1">></span><br />
<span class="kw1">struct</span> allocator<span class="sy4">;</span></span></div></td>
<td> (1) </td>
<td class="t-dcl-nopad"> </td>
</tr>
<tr class="t-dcl">
<td> <div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><></span><br />
<span class="kw1">struct</span> allocator<span class="sy1"><</span><span class="kw4">void</span><span class="sy1">></span><span class="sy4">;</span></span></div></td>
<td> (2) </td>
<td class="t-dcl-nopad"> </td>
</tr>
<tr class="t-dcl-sep"><td></td><td></td><td></td></tr>
</tbody></table>
<p>The <code>std::allocator</code> class template is the default <a href="../concept/Allocator.html" title="cpp/concept/Allocator"><code>Allocator</code></a> used by all standard library containers if no user-specified allocator is provided. The default allocator is stateless, that is, all instances of the given allocator are interchangeable, compare equal and can deallocate memory allocated by any other instance of the same allocator type.
</p><p>Specialization for <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">void</span></span></span> lacks the member typedefs <code>reference</code>, <code>const_reference</code>, <code>size_type</code> and <code>difference_type</code>. This specialization declares no member functions.
</p>
<table class="t-rev-begin">
<tr class="t-rev t-until-cxx11"><td> All custom allocators also must be stateless. </td>
<td><span class="t-mark-rev t-until-cxx11">(until C++11)</span></td></tr>
<tr class="t-rev t-since-cxx11"><td> Custom allocators may contain state. Each container or another allocator-aware object stores an instance of the supplied allocator and controls allocator replacement through <span class="t-lc">std::allocator_traits</span>. </td>
<td><span class="t-mark-rev t-since-cxx11">(since C++11)</span></td></tr>
<tr class="t-rev t-since-cxx17"><td>
The default allocator satisfies <a href="../concept/Allocator.html#Allocator_completeness_requirements" title="cpp/concept/Allocator">allocator completeness requirements</a>. </td>
<td><span class="t-mark-rev t-since-cxx17">(since C++17)</span></td></tr>
</table>
<table id="toc" class="toc"><tr><td><div id="toctitle"><h2>Contents</h2></div>
<ul>
<li class="toclevel-1 tocsection-1"><a href="allocator.html#Member_types"><span class="tocnumber">1</span> <span class="toctext">Member types</span></a></li>
<li class="toclevel-1 tocsection-2"><a href="allocator.html#Member_functions"><span class="tocnumber">2</span> <span class="toctext">Member functions</span></a></li>
<li class="toclevel-1 tocsection-3"><a href="allocator.html#Non-member_functions"><span class="tocnumber">3</span> <span class="toctext">Non-member functions</span></a></li>
<li class="toclevel-1 tocsection-4"><a href="allocator.html#Notes"><span class="tocnumber">4</span> <span class="toctext">Notes</span></a></li>
<li class="toclevel-1 tocsection-5"><a href="allocator.html#Example"><span class="tocnumber">5</span> <span class="toctext">Example</span></a></li>
<li class="toclevel-1 tocsection-6"><a href="allocator.html#See_also"><span class="tocnumber">6</span> <span class="toctext">See also</span></a></li>
</ul>
</td></tr></table>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=cpp/memory/allocator&action=edit&section=1" title="Edit section: Member types">edit</a>]</span> <span class="mw-headline" id="Member_types">Member types</span></h3>
<table class="t-dsc-begin">
<tr class="t-dsc-hitem">
<td> Type
</td>
<td> Definition
</td></tr>
<tr class="t-dsc">
<td> <code>value_type</code>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp">T</span></span>
</td></tr>
<tr class="t-dsc">
<td> <code>pointer</code>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp">T<span class="sy2">*</span></span></span>
</td></tr>
<tr class="t-dsc">
<td> <code>const_pointer</code>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">const</span> T<span class="sy2">*</span></span></span>
</td></tr>
<tr class="t-dsc">
<td> <code>reference</code>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp">T<span class="sy3">&</span></span></span>
</td></tr>
<tr class="t-dsc">
<td> <code>const_reference</code>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">const</span> T<span class="sy3">&</span></span></span>
</td></tr>
<tr class="t-dsc">
<td> <code>size_type</code>
</td>
<td> <span class="t-lc">std::size_t</span>
</td></tr>
<tr class="t-dsc">
<td> <code>difference_type</code>
</td>
<td> <span class="t-lc">std::ptrdiff_t</span>
</td></tr>
<tr class="t-dsc">
<td> <code>propagate_on_container_move_assignment</code><span class="t-mark-rev t-since-cxx14">(C++14)</span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="../types/integral_constant.html"><span class="kw555">std::<span class="me2">true_type</span></span></a></span></span>
</td></tr>
<tr class="t-dsc">
<td> <code>rebind</code>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1"><</span> <span class="kw1">class</span> U <span class="sy1">></span> <span class="kw1">struct</span> rebind <span class="br0">{</span> <span class="kw1">typedef</span> allocator<span class="sy1"><</span>U<span class="sy1">></span> other<span class="sy4">;</span> <span class="br0">}</span><span class="sy4">;</span></span></span>
</td></tr>
<tr class="t-dsc">
<td> <code>is_always_equal</code><span class="t-mark-rev t-since-cxx17">(C++17)</span>
</td>
<td> <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="../types/integral_constant.html"><span class="kw555">std::<span class="me2">true_type</span></span></a></span></span>
</td></tr>
</table>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=cpp/memory/allocator&action=edit&section=2" title="Edit section: Member functions">edit</a>]</span> <span class="mw-headline" id="Member_functions">Member functions</span></h3>
<table class="t-dsc-begin">
<tr class="t-dsc">
<td> <div class="t-dsc-member-div t-dsc-member-nobold-div"><div><a href="allocator/allocator.html" title="cpp/memory/allocator/allocator"> <span class="t-lines"><span>(constructor)</span></span></a></div></div>
</td>
<td> creates a new allocator instance <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/memory/allocator/dsc_allocator&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div t-dsc-member-nobold-div"><div><a href="allocator/~allocator.html" title="cpp/memory/allocator/~allocator"> <span class="t-lines"><span>(destructor)</span></span></a></div></div>
</td>
<td> destructs an allocator instance <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/memory/allocator/dsc_%7Eallocator&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="allocator/address.html" title="cpp/memory/allocator/address"> <span class="t-lines"><span>address</span></span></a></div></div>
</td>
<td> obtains the address of an object, even if <span class="t-c"><span class="mw-geshi cpp source-cpp">operator<span class="sy3">&</span></span></span> is overloaded <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/memory/allocator/dsc_address&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="allocator/allocate.html" title="cpp/memory/allocator/allocate"> <span class="t-lines"><span>allocate</span></span></a></div></div>
</td>
<td> allocates uninitialized storage <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/memory/allocator/dsc_allocate&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="allocator/deallocate.html" title="cpp/memory/allocator/deallocate"> <span class="t-lines"><span>deallocate</span></span></a></div></div>
</td>
<td> deallocates storage <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/memory/allocator/dsc_deallocate&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="allocator/max_size.html" title="cpp/memory/allocator/max size"> <span class="t-lines"><span>max_size</span></span></a></div></div>
</td>
<td> returns the largest supported allocation size <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/memory/allocator/dsc_max_size&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="allocator/construct.html" title="cpp/memory/allocator/construct"> <span class="t-lines"><span>construct</span></span></a></div></div>
</td>
<td> constructs an object in allocated storage <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/memory/allocator/dsc_construct&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="allocator/destroy.html" title="cpp/memory/allocator/destroy"> <span class="t-lines"><span>destroy</span></span></a></div></div>
</td>
<td> destructs an object in allocated storage <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/memory/allocator/dsc_destroy&action=edit">[edit]</a></span>
</td></tr>
</table>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=cpp/memory/allocator&action=edit&section=3" title="Edit section: Non-member functions">edit</a>]</span> <span class="mw-headline" id="Non-member_functions">Non-member functions</span></h3>
<table class="t-dsc-begin">
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="allocator/operator_cmp.html" title="cpp/memory/allocator/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div></div>
</td>
<td> compares two allocator instances <br /> <span class="t-mark">(public member function)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/memory/allocator/dsc_operator_cmp&action=edit">[edit]</a></span>
</td></tr>
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<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=cpp/memory/allocator&action=edit&section=4" title="Edit section: Notes">edit</a>]</span> <span class="mw-headline" id="Notes">Notes</span></h3>
<p>The member template class <code>rebind</code> provides a way to obtain an allocator for a different type. For example,
</p>
<table class="t-rev-begin">
<tr class="t-rev t-until-cxx11"><td> <code>std::list<T, A></code> allocates nodes of some internal type <code>Node<T></code>, using the allocator <span class="t-c"><span class="mw-geshi cpp source-cpp">A<span class="sy4">::</span><span class="me2">rebind</span><span class="sy1"><</span>Node<span class="sy1"><</span>T<span class="sy1">>></span><span class="sy4">::</span><span class="me2">other</span></span></span>
</td>
<td><span class="t-mark-rev t-until-cxx11">(until C++11)</span></td></tr>
<tr class="t-rev t-since-cxx11"><td> <code>std::list<T, A></code> allocates nodes of some internal type <code>Node<T></code>, using the allocator <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="allocator_traits.html"><span class="kw601">std::<span class="me2">allocator_traits</span></span></a><span class="sy1"><</span>A<span class="sy1">></span><span class="sy4">::</span><span class="me2">rebind_alloc</span><span class="sy1"><</span>Node<span class="sy1"><</span>T<span class="sy1">>></span></span></span>, which is implemented in terms of <span class="t-c"><span class="mw-geshi cpp source-cpp">A<span class="sy4">::</span><span class="me2">rebind</span><span class="sy1"><</span>Node<span class="sy1"><</span>T<span class="sy1">>></span><span class="sy4">::</span><span class="me2">other</span></span></span> if A is an <code>std::allocator</code>
</td>
<td><span class="t-mark-rev t-since-cxx11">(since C++11)</span></td></tr>
</table>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=cpp/memory/allocator&action=edit&section=5" title="Edit section: Example">edit</a>]</span> <span class="mw-headline" id="Example">Example</span></h3>
<div class="t-example"><div class="t-example-live-link"><div class="coliru-btn coliru-btn-run-init">Run this code</div></div>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="co2">#include <memory></span>
<span class="co2">#include <iostream></span>
<span class="co2">#include <string></span>
 
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
<span class="br0">{</span>
std<span class="sy4">::</span><span class="me2">allocator</span><span class="sy1"><</span><span class="kw4">int</span><span class="sy1">></span> a1<span class="sy4">;</span> <span class="co1">// default allocator for ints</span>
<span class="kw4">int</span><span class="sy2">*</span> a <span class="sy1">=</span> a1.<span class="me1">allocate</span><span class="br0">(</span><span class="nu0">10</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// space for 10 ints</span>
 
a<span class="br0">[</span><span class="nu0">9</span><span class="br0">]</span> <span class="sy1">=</span> <span class="nu0">7</span><span class="sy4">;</span>
 
<a href="../io/cout.html"><span class="kw1480">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> a<span class="br0">[</span><span class="nu0">9</span><span class="br0">]</span> <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
 
a1.<span class="me1">deallocate</span><span class="br0">(</span>a, <span class="nu0">10</span><span class="br0">)</span><span class="sy4">;</span>
 
<span class="co1">// default allocator for strings</span>
std<span class="sy4">::</span><span class="me2">allocator</span><span class="sy1"><</span><a href="../string/basic_string.html"><span class="kw1071">std::<span class="me2">string</span></span></a><span class="sy1">></span> a2<span class="sy4">;</span>
 
<span class="co1">// same, but obtained by rebinding from the type of a1</span>
decltype<span class="br0">(</span>a1<span class="br0">)</span><span class="sy4">::</span><span class="me2">rebind</span><span class="sy1"><</span><a href="../string/basic_string.html"><span class="kw1071">std::<span class="me2">string</span></span></a><span class="sy1">></span><span class="sy4">::</span><span class="me2">other</span> a2_1<span class="sy4">;</span>
 
<span class="co1">// same, but obtained by rebinding from the type of a1 via allocator_traits</span>
<a href="allocator_traits.html"><span class="kw601">std::<span class="me2">allocator_traits</span></span></a><span class="sy1"><</span>decltype<span class="br0">(</span>a1<span class="br0">)</span><span class="sy1">></span><span class="sy4">::</span><span class="me2">rebind_alloc</span><span class="sy1"><</span><a href="../string/basic_string.html"><span class="kw1071">std::<span class="me2">string</span></span></a><span class="sy1">></span> a2_2<span class="sy4">;</span>
 
<a href="../string/basic_string.html"><span class="kw1071">std::<span class="me2">string</span></span></a><span class="sy2">*</span> s <span class="sy1">=</span> a2.<span class="me1">allocate</span><span class="br0">(</span><span class="nu0">2</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// space for 2 strings</span>
 
a2.<span class="me1">construct</span><span class="br0">(</span>s, <span class="st0">"foo"</span><span class="br0">)</span><span class="sy4">;</span>
a2.<span class="me1">construct</span><span class="br0">(</span>s <span class="sy2">+</span> <span class="nu0">1</span>, <span class="st0">"bar"</span><span class="br0">)</span><span class="sy4">;</span>
 
<a href="../io/cout.html"><span class="kw1480">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> s<span class="br0">[</span><span class="nu0">0</span><span class="br0">]</span> <span class="sy1"><<</span> <span class="st0">' '</span> <span class="sy1"><<</span> s<span class="br0">[</span><span class="nu0">1</span><span class="br0">]</span> <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
 
a2.<span class="me1">destroy</span><span class="br0">(</span>s<span class="br0">)</span><span class="sy4">;</span>
a2.<span class="me1">destroy</span><span class="br0">(</span>s <span class="sy2">+</span> <span class="nu0">1</span><span class="br0">)</span><span class="sy4">;</span>
a2.<span class="me1">deallocate</span><span class="br0">(</span>s, <span class="nu0">2</span><span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<p>Output:
</p>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="text source-text"><pre class="de1">7
foo bar</pre></div></div>
</div>
<h3><span class="editsection">[<a href="http://en.cppreference.com/mwiki/index.php?title=cpp/memory/allocator&action=edit&section=6" title="Edit section: See also">edit</a>]</span> <span class="mw-headline" id="See_also">See also</span></h3>
<table class="t-dsc-begin">
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="allocator_traits.html" title="cpp/memory/allocator traits"> <span class="t-lines"><span>allocator_traits</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td> provides information about allocator types <br /> <span class="t-mark">(class template)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/memory/dsc_allocator_traits&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="scoped_allocator_adaptor.html" title="cpp/memory/scoped allocator adaptor"> <span class="t-lines"><span>scoped_allocator_adaptor</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td> implements multi-level allocator for multi-level containers <br /> <span class="t-mark">(class template)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/memory/dsc_scoped_allocator_adaptor&action=edit">[edit]</a></span>
</td></tr>
<tr class="t-dsc">
<td> <div class="t-dsc-member-div"><div><a href="uses_allocator.html" title="cpp/memory/uses allocator"> <span class="t-lines"><span>uses_allocator</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td> checks if the specified type supports uses-allocator construction <br /> <span class="t-mark">(class template)</span> <span class="editsection noprint plainlinks" title="Edit this template"><a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/memory/dsc_uses_allocator&action=edit">[edit]</a></span>
</td></tr>
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