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POCloseHandle confusion - Must I call CloseHandle on multiple "copies" of a handle?
 

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  1. POCloseHandle confusion - Must I call CloseHandle on multiple "copies" of a handle?
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    <p>I have some (more) questions about calling CloseHandle.</p> <p>So, <a href="https://stackoverflow.com/questions/3959473/must-i-closehandle-on-a-thread-handle">the SO citizens have spoken, and you must always close a handle</a>. </p> <p><strong>Question 1</strong></p> <p>I've written the following code snippet in a destructor:</p> <pre><code>HANDLE handles[] = { m_hGrabberThread, m_hCtrlThread, m_hErrDispatchThread }; int nNumHandles = sizeof(handles) / sizeof(handles[0]); for( int n = 0; n &lt; nNumHandles; n ++ ) CloseHandle( handles[n] ); </code></pre> <p>Is the above code valid, or must I call CloseHandle() on each handle member variable individually?</p> <p>e.g.</p> <pre><code>if( m_hCtrlThread != INVALID_HANDLE_VALUE ) CloseHandle( m_hCtrlThread ); </code></pre> <p>I suppose that this question is linked (vaguely) to question 2...</p> <p><strong>Question 2</strong></p> <p>I have a class that creates an event handle:</p> <pre><code>HANDLE hEventAbortProgram = CreateEvent( NULL, TRUE, FALSE, NULL ); </code></pre> <p>This handle is shared among other threads in other objects.</p> <p>By sharing the handle, I mean:</p> <pre><code>objectB.m_hEventAbort = objectA.m_hEventAbort; </code></pre> <p>Each object's threads will then do something like:</p> <pre><code>while( WaitForSingleObject(m_hEventAbort, 0) == WAIT_TIMEOUT ) {...} </code></pre> <p>When the event is signaled, all threads will exit.</p> <p>My question is: must I call CloseHandle on each copy of the handle, or just once in my main "parent" object? </p> <p>I suppose that I'm asking - are handles reference counted when they're copied? </p> <p>I know that a handle is only a typedef for a void*, so my instinct says no, I only need to call it once per handle.</p>
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    1. COI doubt that calling `CloseHandle(INVALID_HANDLE_VALUE)` will do any harm, so why bothering checking it?
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    2. COHave a peek at http://stackoverflow.com/questions/1562421/making-a-handle-raii-compliant-using-shared-ptr-with-a-custom-deleter ; you might be able to use Boost for the bookkeeping.
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