[Bug 3930] HOMM/Deadlock shows black screen (game DLL calls SuspendThread inside WOM_OPEN winmm callback)

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=3930

--- Comment #88 from zebra2745(a)vibzi.net ---
> That doesn't work, because GetCurrentThread() only returns a pseudo handle,
> "a special constant that is interpreted as the current thread handle"
> (MSDN). I think we have to compare the globally unique thread IDs to be sure:

https://www.codeproject.com/Tips/5350589/The-Current-Thread-Handle says:
> What to do when you want to use the current thread handle
> This tip shows a side effect of GetCurrentThread and explains what to do when you need to avoid that.
> Introduction
> When you need to get a handle to the current thread, you can use
> GetCurrentThread which gives you a pseudo handle which you don't need to close
> because it is not a real reference counted handle. This is mentioned clearly in
> the documentation. However, I recently bumped my head against this. I wanted to
> share it so that others can avoid having to chase this down.
> My Headbump
> Consider the following example:
> ------------------------------ snip ------------------------------

DWORD worker(void* ctx)
{
    std::cout << "Thread id: " << GetThreadId((HANDLE)ctx) << std::endl;
    return 0;
}

int main()
{
    HANDLE hMainThread = GetCurrentThread();
    std::cout << "Thread id: " << GetThreadId(hMainThread) << std::endl;

    HANDLE hThread = CreateThread(NULL, 0, worker, hMainThread, 0, NULL);
    WaitForSingleObject(hThread, INFINITE);    
}
> ------------------------------ snip ------------------------------
> This is what happens:
> Thread id: 44068
> Thread id: 36376
> Without thinking, I had assumed that the pseudo handle was just a weak copy of
> the actual handle (a non reference counted copy of the current handle), and I
> could reference it in a worker thread. Instead, it is a special constant that
> literally means 'when this handle value is supplied, use the current thread'.
> And if you pass that special value to another thread, then that value will
> translate to the thread handle of 'that' thread.
> If you read the documentation, then this is exactly what it says. Only I
> didn't stop to think about what that actually meant.
> Getting the Real Thread Handle
> If you want to get a real handle that you can pass to another thread, do this:
> ------------------------------ snip ------------------------------

HANDLE hMainThread = NULL;
if (!DuplicateHandle(
    GetCurrentProcess(),
    GetCurrentThread(),
    GetCurrentProcess(),
    &hMainThread,
    0,
    FALSE,
    DUPLICATE_SAME_ACCESS)) {
    cout << "Error " << GetLastError() << " cannot duplicate main handle." <<
endl;
    return GetLastError();
}
> ------------------------------ snip ------------------------------
> Of course, when you do this, you get a HANDLE value that you do need to close
> when you no longer need it.

-- 
Do not reply to this email, post in Bugzilla using the
above URL to reply.
You are receiving this mail because:
You are watching all bug changes.