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Fix doc errors, add shared_ptr_example program
[SVN r10165]
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@ -106,7 +106,7 @@ output:</p>
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Buckle my shoe</pre>
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</blockquote>
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<h2>Handle/Body Idiom</h2>
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<p>One common usage of <b>shared_pointer</b> is to implement a handle/body
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<p>One common usage of <b>scoped_ptr</b> is to implement a handle/body
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structure which avoids exposing the body (implementation) in the header file:</p>
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<pre>class handle
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{
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@ -123,7 +123,7 @@ body</code> is not visible at the time scoped_ptr<> deletes it. See ISO
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5.3.5/5. Note that some compilers will issue a warning even though the
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above code is well defined.</p>
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<hr>
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<p>Revised <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %B %Y" startspan -->10 May 2001<!--webbot bot="Timestamp" endspan i-checksum="15101" --></p>
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<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>
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<p><EFBFBD> Copyright Greg Colvin and Beman Dawes 1999. Permission to copy, use,
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modify, sell and distribute this document is granted provided this copyright
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notice appears in all copies. This document is provided "as is"
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@ -192,33 +192,17 @@ stored pointer.</p>
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<p><code>void swap( shared_ptr<T>& other ) throw()</code></p>
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<p>Swaps the two smart pointers, as if by std::swap.</p>
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<h2>Class <a name="shared_ptr_example">shared_ptr example</a></h2>
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<pre>// The application will produce a series of
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// objects of type Foo which later must be
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// accessed both by occurrence (std::vector)
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// and by ordering relationship (std::set).
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class Foo { ... };
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typedef boost::shared_ptr<Foo> FooPtr;
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std::vector<FooPtr> foo_vector;
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std::set<FooPtr> foo_set; // NOT multiset!
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...
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{ // creation loop
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FooPtr foo_ptr ( new Foo( ... ) );
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foo_vector.push_back( foo_ptr );
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foo_set.insert( foo_ptr );
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}</pre>
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<p>Note that at the termination of the creation loop, some of the FooPtr objects
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may have use_count()==1 rather than use_count()==2, since foo_set is a std::set
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rather than a std::multiset. Furthermore, use_count() will be even higher
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at various times inside the loop, as container operations are performed.
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<p>See <a href="shared_ptr_example.cpp"> shared_ptr_example.cpp</a> for a complete example program.</p>
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<p>This program builds a std::vector and std::set of FooPtr's.</p>
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<p>Note that after the two containers have been populated, some of the FooPtr objects
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will have use_count()==1 rather than use_count()==2, since foo_set is a std::set
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rather than a std::multiset. Furthermore, use_count() may be even higher
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at various times while push_back() and insert() container operations are performed.
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More complicated yet, the container operations may throw exceptions under a
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variety of circumstances. Without using a smart pointer, memory and
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exception management would be a nightmare.</p>
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<hr>
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<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->10 February, 2001<!--webbot bot="Timestamp" endspan i-checksum="40395" -->
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<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->21 May, 2001<!--webbot bot="Timestamp" endspan i-checksum="13958" -->
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</p>
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<p><EFBFBD> Copyright Greg Colvin and Beman Dawes 1999. Permission to copy, use,
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modify, sell and distribute this document is granted provided this copyright
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96
shared_ptr_example.cpp
Normal file
96
shared_ptr_example.cpp
Normal file
@ -0,0 +1,96 @@
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// Boost shared_ptr_example.cpp --------------------------------------------//
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// (C) Copyright Beman Dawes 2001. Permission to copy,
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// use, modify, sell and distribute this software is granted provided this
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// copyright notice appears in all copies. This software is provided "as is"
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// without express or implied warranty, and with no claim as to its
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// suitability for any purpose.
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// See http://www.boost.org for most recent version including documentation.
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// Revision History
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// 21 May 01 Initial complete version (Beman Dawes)
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// The original code for this example appeared in the shared_ptr documentation.
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// Ray Gallimore pointed out that foo_set was missing a Compare template
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// argument, so would not work as intended. At that point the code was
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// turned into an actual .cpp file so it could be compiled and tested.
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#include <vector>
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#include <set>
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#include <iostream>
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#include <algorithm>
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#include <boost/smart_ptr.hpp>
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// The application will produce a series of
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// objects of type Foo which later must be
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// accessed both by occurrence (std::vector)
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// and by ordering relationship (std::set).
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struct Foo
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{
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Foo( int _x ) : x(_x) {}
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~Foo() { std::cout << "Destructing a Foo with x=" << x << "\n"; }
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int x;
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/* ... */
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};
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typedef boost::shared_ptr<Foo> FooPtr;
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struct FooPtrOps
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{
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bool operator()( const FooPtr & a, const FooPtr & b )
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{ return a->x > b->x; }
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void operator()( const FooPtr & a )
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{ std::cout << a->x << "\n"; }
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};
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int main()
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{
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std::vector<FooPtr> foo_vector;
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std::set<FooPtr,FooPtrOps> foo_set; // NOT multiset!
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FooPtr foo_ptr( new Foo( 2 ) );
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foo_vector.push_back( foo_ptr );
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foo_set.insert( foo_ptr );
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foo_ptr.reset( new Foo( 1 ) );
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foo_vector.push_back( foo_ptr );
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foo_set.insert( foo_ptr );
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foo_ptr.reset( new Foo( 3 ) );
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foo_vector.push_back( foo_ptr );
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foo_set.insert( foo_ptr );
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foo_ptr.reset ( new Foo( 2 ) );
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foo_vector.push_back( foo_ptr );
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foo_set.insert( foo_ptr );
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std::cout << "foo_vector:\n";
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std::for_each( foo_vector.begin(), foo_vector.end(), FooPtrOps() );
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std::cout << "\nfoo_set:\n";
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std::for_each( foo_set.begin(), foo_set.end(), FooPtrOps() );
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std::cout << "\n";
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// Expected output:
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//
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// foo_vector:
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// 2
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// 1
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// 3
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// 2
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//
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// foo_set:
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// 3
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// 2
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// 1
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//
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// Destructing a Foo with x=2
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// Destructing a Foo with x=1
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// Destructing a Foo with x=3
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// Destructing a Foo with x=2
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return 0;
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}
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