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<HTML><!-- -- Copyright (c) 1996-1999 -- Silicon Graphics Computer Systems, Inc. -- -- Permission to use, copy, modify, distribute and sell this software -- and its documentation for any purpose is hereby granted without fee, -- provided that the above copyright notice appears in all copies and -- that both that copyright notice and this permission notice appear -- in supporting documentation. Silicon Graphics makes no -- representations about the suitability of this software for any -- purpose. It is provided "as is" without express or implied warranty. -- -- Copyright (c) 1994 -- Hewlett-Packard Company -- -- Permission to use, copy, modify, distribute and sell this software -- and its documentation for any purpose is hereby granted without fee, -- provided that the above copyright notice appears in all copies and -- that both that copyright notice and this permission notice appear -- in supporting documentation. 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It is provided "as is" without express or implied warranty. -- --><Head><Title>destroy</Title><!-- Generated by htmldoc --></HEAD><BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b" ALINK="#ff0000"> <IMG SRC="CorpID.gif" ALT="SGI" HEIGHT="43" WIDTH="151"> <!--end header--><BR Clear><H1>destroy</H1><Table CellPadding=0 CellSpacing=0 width=100%><TR><TD Align=left><Img src = "allocators.gif" Alt="" WIDTH = "194" HEIGHT = "38" ></TD><TD Align=right><Img src = "function.gif" Alt="" WIDTH = "194" HEIGHT = "38" ></TD></TR><TR><TD Align=left VAlign=top><b>Category</b>: allocators</TD><TD Align=right VAlign=top><b>Component type</b>: function</TD></TR></Table><h3>Prototype</h3><tt>Destroy</tt> is an overloaded name; there are actually two <tt>destroy</tt>functions.<pre>template <class T> void destroy(T* pointer);template <class <A href="ForwardIterator.html">ForwardIterator</A>>void destroy(ForwardIterator first, ForwardIterator last);</pre> <h3>Description</h3>In C++, the operator <tt>delete</tt> destroys an object by calling itsdestructor, and then deallocates the memory where that object wasstored. Occasionally, however, it is useful to separate those twooperations. <A href="#1">[1]</A> <tt>Destroy</tt> calls an object's destructor without deallocating the memory where the object was stored.<P>The first version of <tt>destroy</tt>destroys the object pointed to by <tt>pointer</tt> by calling the destructor <tt>T::~T()</tt>. The memory pointed to by <tt>pointer</tt> is notdeallocated, and can be reused for some other object.<P>The second version of <tt>destroy</tt>destroys all of the objects in the range of elements <tt>[first, last)</tt>.It is equivalent to calling <tt>destroy(&*i)</tt> for each iterator <tt>i</tt>in the range <tt>[first, last)</tt>.<h3>Definition</h3>Defined in the standard header <A href="memory">memory</A>, and in the nonstandardbackward-compatibility header <A href="algo.h">algo.h</A>. The <tt>destroy</tt> algorithmsare no longer part of the C++ standard; they were present in early drafts,and they are retained in this implementation for backward compatibility.<h3>Requirements on types</h3>For the first version of <tt>destroy</tt>:<UL><LI><tt>T</tt>'s destructor, <tt>~T</tt>, is accessible.</UL>For the second version of <tt>destroy</tt>:<UL><LI><tt>ForwardIterator</tt> is a model of <A href="ForwardIterator.html">Forward Iterator</A>.<LI><tt>ForwardIterator</tt> is mutable.<LI><tt>ForwardIterator</tt>'s value type has an accessible destructor.</UL><h3>Preconditions</h3>For the first version of <tt>destroy</tt>:<UL><LI><tt>pointer</tt> points to a valid object of type <tt>T</tt>.</UL>For the second version of <tt>destroy</tt>:<UL><LI><tt>[first, last)</tt> is a valid range.<LI>Each iterator <tt>i</tt> in <tt>[first, last)</tt> points to a valid object.</UL><h3>Complexity</h3>The run-time complexity of the second version is linear: it calls the destructor exactly <tt>last - first</tt> times.<h3>Example</h3><pre>class Int {public: Int(int x) : val(x) {} int get() { return val; }private: int val;};int main(){ Int A[] = { Int(1), Int(2), Int(3), Int(4) }; destroy(A, A + 4); construct(A, Int(10)); construct(A + 1, Int(11)); construct(A + 2, Int(12)); construct(A + 3, Int(13));}</pre><h3>Notes</h3><P><A name="1">[1]</A>In particular, <tt>destroy</tt>, along with other low-level memory allocation primitives, is used to implement container classes.<h3>See also</h3><A href="Allocators.html">Allocators</A>, <tt><A href="construct.html">construct</A></tt>, <tt><A href="uninitialized_copy.html">uninitialized_copy</A></tt>, <tt><A href="uninitialized_fill.html">uninitialized_fill</A></tt>, <tt><A href="uninitialized_fill_n.html">uninitialized_fill_n</A></tt>,<tt><A href="raw_storage_iterator.html">raw_storage_iterator</A></tt><!--start footer--> <HR SIZE="6"><A href="http://www.sgi.com/"><IMG SRC="surf.gif" HEIGHT="54" WIDTH="54" ALT="[Silicon Surf]"></A><A HREF="index.html"><IMG SRC="stl_home.gif" HEIGHT="54" WIDTH="54" ALT="[STL Home]"></A><BR><FONT SIZE="-2"><A href="http://www.sgi.com/Misc/sgi_info.html" TARGET="_top">Copyright © 1999 Silicon Graphics, Inc.</A> All Rights Reserved.</FONT><FONT SIZE="-3"><a href="http://www.sgi.com/Misc/external.list.html" TARGET="_top">TrademarkInformation</A></FONT><P></BODY></HTML> ⌨️ 快捷键说明
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