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diff --git a/gcc-4.4.3/libstdc++-v3/doc/xml/manual/auto_ptr.xml b/gcc-4.4.3/libstdc++-v3/doc/xml/manual/auto_ptr.xml deleted file mode 100644 index a7a0e97bc..000000000 --- a/gcc-4.4.3/libstdc++-v3/doc/xml/manual/auto_ptr.xml +++ /dev/null @@ -1,133 +0,0 @@ -<sect1 id="manual.util.memory.auto_ptr" xreflabel="auto_ptr"> -<?dbhtml filename="auto_ptr.html"?> - -<sect1info> - <keywordset> - <keyword> - ISO C++ - </keyword> - <keyword> - auto_ptr - </keyword> - </keywordset> -</sect1info> - -<title>auto_ptr</title> - -<sect2 id="auto_ptr.limitations" xreflabel="auto_ptr.limitations"> -<title>Limitations</title> - - <para>Explaining all of the fun and delicious things that can - happen with misuse of the <classname>auto_ptr</classname> class - template (called <acronym>AP</acronym> here) would take some - time. Suffice it to say that the use of <acronym>AP</acronym> - safely in the presence of copying has some subtleties. - </para> - <para> - The AP class is a really - nifty idea for a smart pointer, but it is one of the dumbest of - all the smart pointers -- and that's fine. - </para> - <para> - AP is not meant to be a supersmart solution to all resource - leaks everywhere. Neither is it meant to be an effective form - of garbage collection (although it can help, a little bit). - And it can <emphasis>not</emphasis>be used for arrays! - </para> - <para> - <acronym>AP</acronym> is meant to prevent nasty leaks in the - presence of exceptions. That's <emphasis>all</emphasis>. This - code is AP-friendly: - </para> - <programlisting> - // Not a recommend naming scheme, but good for web-based FAQs. - typedef std::auto_ptr<MyClass> APMC; - - extern function_taking_MyClass_pointer (MyClass*); - extern some_throwable_function (); - - void func (int data) - { - APMC ap (new MyClass(data)); - - some_throwable_function(); // this will throw an exception - - function_taking_MyClass_pointer (ap.get()); - } - </programlisting> - <para>When an exception gets thrown, the instance of MyClass that's - been created on the heap will be <function>delete</function>'d as the stack is - unwound past <function>func()</function>. - </para> - <para>Changing that code as follows is not <acronym>AP</acronym>-friendly: - </para> - <programlisting> - APMC ap (new MyClass[22]); - </programlisting> - <para>You will get the same problems as you would without the use - of <acronym>AP</acronym>: - </para> - <programlisting> - char* array = new char[10]; // array new... - ... - delete array; // ...but single-object delete - </programlisting> - <para> - AP cannot tell whether the pointer you've passed at creation points - to one or many things. If it points to many things, you are about - to die. AP is trivial to write, however, so you could write your - own <code>auto_array_ptr</code> for that situation (in fact, this has - been done many times; check the mailing lists, Usenet, Boost, etc). - </para> -</sect2> - -<sect2 id="auto_ptr.using" xreflabel="auto_ptr.using"> -<title>Use in Containers</title> - - <para> - </para> - <para>All of the <ulink url="../23_containers/howto.html">containers</ulink> - described in the standard library require their contained types - to have, among other things, a copy constructor like this: - </para> - <programlisting> - struct My_Type - { - My_Type (My_Type const&); - }; - </programlisting> - <para> - Note the const keyword; the object being copied shouldn't change. - The template class <code>auto_ptr</code> (called AP here) does not - meet this requirement. Creating a new AP by copying an existing - one transfers ownership of the pointed-to object, which means that - the AP being copied must change, which in turn means that the - copy ctors of AP do not take const objects. - </para> - <para> - The resulting rule is simple: <emphasis>Never ever use a - container of auto_ptr objects</emphasis>. The standard says that - <quote>undefined</quote> behavior is the result, but it is - guaranteed to be messy. - </para> - <para> - To prevent you from doing this to yourself, the - <ulink url="../19_diagnostics/howto.html#3">concept checks</ulink> built - in to this implementation will issue an error if you try to - compile code like this: - </para> - <programlisting> - #include <vector> - #include <memory> - - void f() - { - std::vector< std::auto_ptr<int> > vec_ap_int; - } - </programlisting> - <para> -Should you try this with the checks enabled, you will see an error. - </para> -</sect2> - -</sect1>
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