Re: Is this ok?

"Doug Harrison [MVP]" <>
Mon, 31 Mar 2008 10:24:29 -0500
On Sun, 30 Mar 2008 06:38:05 +0200, "Lisa Pearlson" <no@spam.plz> wrote:

Is it ok for a thread to close the handle to itself?

Only if it is a handle no one else is using. See Q1 and Q2 here:


DWORD g_hThread = NULL;

The NULL macro is a code comment that implies "pointer", and you should
remember not to use it with integer types like DWORD. However, you should
have declared g_hThread as a HANDLE, which if you look at the source, is a
pointer type.

LONG ThreadFunc(LPVOID *pVoid)
   // do stuff here
   // self-delete
   g_hThread = NULL;

g_hThread = CreateThread(...., ThreadFunc, ...);

This is bad because there is a race condition between the creating thread
setting g_hThread and the new thread using it. Per the web page cited
above, it's also bad because the creating thread doesn't join with the new
thread, and if it did use WaitForSingleObject(g_hThread), it would be
undefined, since the new thread would close g_hThread during the wait.

Doug Harrison
Visual C++ MVP

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