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POMaking a HANDLE RAII-compliant using shared_ptr with a custom deleter
 

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    <p>I've recently posted a general question about RAII at <a href="https://stackoverflow.com/questions/1556168/making-a-non-object-resource-raii-compliant">SO</a>. However, I still have some implementation issues with my HANDLE example.</p> <p>A <code>HANDLE</code> is typedeffed to <code>void *</code> in <code>windows.h</code>. Therefore, the correct <code>shared_ptr</code> definition needs to be </p> <pre><code>std::tr1::shared_ptr&lt;void&gt; myHandle (INVALID_HANDLE_VALUE, CloseHandle); </code></pre> <p><strong>Example 1</strong> <code>CreateToolhelp32Snapshot</code>: returns <code>HANDLE</code> and works.</p> <pre><code>const std::tr1::shared_ptr&lt;void&gt; h (CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, NULL), CloseHandle); </code></pre> <p>As I use <code>void</code> in the definition (what is the correct way?) problems go on, when I try to call some more winapi commands with this pointer. They functionally work, but are ugly and I am sure that there has to be a better solution.</p> <p>In the following examples, <code>h</code> is a pointer which was created via the definition at the top.</p> <p><strong>Example 2</strong> <code>OpenProcessToken</code>: last argument is a <code>PHANDLE</code>. medium ugly with the cast.</p> <pre><code>OpenProcessToken(GetCurrentProcess(), TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, (PHANDLE)&amp;h); </code></pre> <p><strong>Example 3</strong> <code>Process32First</code>: first argument is a <code>HANDLE</code>. REALLY ugly.</p> <pre><code>Process32First(*((PHANDLE)&amp;h), &amp;pEntry); </code></pre> <p><strong>Example 4</strong> simple comparison with a constant <code>HANDLE</code>. REALLY ugly.</p> <pre><code>if (*((PHANDLE)&amp;h) == INVALID_HANDLE) { /* do something */ } </code></pre> <p>What is the correct way to create a proper shared_ptr for a HANDLE?</p>
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