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New casts for smart pointers.

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[SVN r12743]
This commit is contained in:
Darin Adler
2002-02-06 19:42:04 +00:00
parent f9782387d9
commit 0dd3285d56
4 changed files with 86 additions and 5 deletions
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weak_ptr.htm
+22 -2
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@@ -71,6 +71,10 @@ pointed to. <b>T</b> must meet the smart pointer
weak_ptr&lt;T&gt <a href="#shared_static_cast">shared_static_cast</a>(weak_ptr&lt;U&gt; const &amp; r); // never throws
template&lt;typename T, typename U&gt;
weak_ptr&lt;T&gt <a href="#shared_dynamic_cast">shared_dynamic_cast</a>(weak_ptr&lt;U&gt; const &amp; r);
template&lt;typename T, typename U&gt;
weak_ptr&lt;T&gt <a href="#shared_polymorphic_cast">shared_polymorphic_cast</a>(weak_ptr&lt;U&gt; const &amp; r);
template&lt;typename T, typename U&gt;
weak_ptr&lt;T&gt <a href="#shared_polymorphic_downcast">shared_polymorphic_downcast</a>(weak_ptr&lt;U&gt; const &amp; r); // never throws
}</pre>
@@ -192,19 +196,35 @@ Provided as an aid to generic programming.</p>
<h3><a name="shared_static_cast">shared_static_cast</a></h3>
<pre>template&lt;typename T, typename U&gt;
weak_ptr&lt;T&gt <a href="#shared_static_cast">shared_static_cast</a>(weak_ptr&lt;U&gt; const &amp; r); // never throws</pre>
weak_ptr&lt;T&gt shared_static_cast(weak_ptr&lt;U&gt; const &amp; r); // never throws</pre>
<p>Perform a <b>static_cast</b> on the stored pointer, returning another <b>weak_ptr</b>.
The resulting smart pointer will share its use count with the original pointer.</p>
<h3><a name="shared_dynamic_cast">shared_dynamic_cast</a></h3>
<pre>template&lt;typename T, typename U&gt;
weak_ptr&lt;T&gt <a href="#shared_dynamic_cast">shared_dynamic_cast</a>(weak_ptr&lt;U&gt; const &amp; r);</pre>
weak_ptr&lt;T&gt shared_dynamic_cast(weak_ptr&lt;U&gt; const &amp; r);</pre>
<p>Perform a <b>dynamic_cast</b> on the stored pointer, returning another <b>weak_ptr</b>.
The resulting smart pointer will share its use count with the original pointer unless the result of the
cast is 0. The only exception which may be thrown is <b>std::bad_alloc</b>, which may be thrown during the
construction of the new <b>weak_ptr</b> if the result of the cast is 0. If an exception is thrown, the
cast has no effect.</p>
<h3><a name="shared_polymorphic_cast">shared_polymorphic_cast</a></h3>
<pre>template&lt;typename T, typename U&gt;
weak_ptr&lt;T&gt shared_polymorphic_cast(weak_ptr&lt;U&gt; const &amp; r);</pre>
<p>Perform a <a href="../conversion/cast.htm#Polymorphic_cast"><b>polymorphic_cast</b><a> on the stored pointer,
returning another <b>weak_ptr</b>.
The resulting smart pointer will share its use count with the original pointer.
The only exception which may be thrown is <b>std::bad_cast</b>, if the pointer type can not be converted.
If an exception is thrown, the cast has no effect.</p>
<h3><a name="shared_polymorphic_downcast">shared_polymorphic_downcast</a></h3>
<pre>template&lt;typename T, typename U&gt;
weak_ptr&lt;T&gt shared_polymorphic_downcast(weak_ptr&lt;U&gt; const &amp; r); // never throws</pre>
<p>Perform a <a href="../conversion/cast.htm#Polymorphic_cast"><b>polymorphic_downcast</b><a> on the stored pointer,
returning another <b>weak_ptr</b>.
The resulting smart pointer will share its use count with the original pointer.</p>
<hr>
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B %Y" startspan -->1 February 2002<!--webbot bot="Timestamp" i-checksum="38439" endspan --></p>