WCT GetThreadWaitChain call allways return false

Question

I am trying to get WCT information about some thread, but every time I am calling GetThreadWaitChain function I am getting false as a response and the ref parameters remain zero.

What am I doing wrong?

I am calling this function on a thread which calls WaitForMultipleObjects, and I am making sure that this thread waits while I am debugging.

That's my code:

    internal void CollectWaitInformation(ClrThread thread)
    {
        var g_WctHandle = OpenThreadWaitChainSession(0, 0);

        uint threadID = thread.OSThreadId;

        WAITCHAIN_NODE_INFO[] NodeInfoArray = new WAITCHAIN_NODE_INFO[WCT_MAX_NODE_COUNT];


        int isCycle = 0;
        int count = 0;

        // Make a synchronous WCT call to retrieve the wait chain.
        bool result = GetThreadWaitChain(g_WctHandle,
                                IntPtr.Zero,
                                WCTP_GETINFO_ALL_FLAGS,
                                threadID, ref count, NodeInfoArray, out isCycle);

        if (!result)
        {
            //error
        }

        //Finaly ...
        CloseSession(g_WctHandle);
    }

    [DllImport("Advapi32.dll")]
    public static extern IntPtr OpenThreadWaitChainSession(OpenThreadChainFlags Flags, DWORD callback);

    [DllImport("Advapi32.dll")]
    public static extern bool GetThreadWaitChain(
        IntPtr WctHandle,
        IntPtr Context,
        UInt32 Flags,
        uint ThreadId,
        ref int NodeCount,
        [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 4)]
        [In, Out]
        WAITCHAIN_NODE_INFO[] NodeInfoArray,
        out int IsCycle
    );

    [StructLayout(LayoutKind.Sequential)]
    public struct WAITCHAIN_NODE_INFO
    {
        public WCT_OBJECT_TYPE ObjectType;
        public WCT_OBJECT_STATUS ObjectStatus;

        public struct LockObject
        {
            string ObjectName;
            LARGE_INTEGER Timeout;
            BOOL Alertable;
        }
        public struct ThreadObject
        {
            DWORD ProcessId;
            DWORD ThreadId;
            DWORD WaitTime;
            DWORD ContextSwitches;
        }
    }
}

}

With a help from my previous question:

Calling C++ method from C# with pointer parameter (WCT)

Answer 1

From the documentation:

NodeCount [in, out]

On input, a number from 1 to WCT_MAX_NODE_COUNT that specifies the number of nodes in the wait chain. On return, the number of nodes retrieved.

....

You fail to meet this requirement because you pass in 0.