Readfile() and GetOverlappedResult() return lpNumberOfBytesTransferred lenght problem.

Question

I have a question
I declared a USB HID DEVICE, HID report as follows:
Usage Page (Vendor-Defined 1)
06 00 FF 
Usage (Vendor-Defined 2)
09 02 
Collection (Application)
A1 01 
    Logical Minimum (0)
15 00 
    Logical Maximum (255)
26 FF 00 
    Report Size (8)
75 08 
    Report ID (1)
85 01 
    Report Count (7)
95 07 
    Usage (Vendor-Defined 2)
09 02 
    Input (Data,Var,Abs,NWrp,Lin,Pref,NNul,Bit)
81 02 
    Usage (Vendor-Defined 2)
09 02 
    Output (Data,Var,Abs,NWrp,Lin,Pref,NNul,NVol,Bit)
91 02 
    Report ID (2)
85 02 
    Report Count (63)
95 3F 
    Usage (Vendor-Defined 2)
09 02 
    Input (Data,Var,Abs,NWrp,Lin,Pref,NNul,Bit)
81 02 
    Usage (Vendor-Defined 2)
09 02 
    Output (Data,Var,Abs,NWrp,Lin,Pref,NNul,NVol,Bit)
91 02 
End Collection
C0 
USB HID device success send 8 bytes data to pc. (01 35 00 00 00 00 00 00)
Part of the source code:
memset(ReadReportBuffer, 0, sizeof(ReadReportBuffer));
ReadFile(m_hReadHandle,
ReadReportBuffer,
64,
NULL,
&ReadOverlapped);
dObject = WaitForMultipleObjects(2, hArray, FALSE, INFINITE);
if (dObject == WAIT_OBJECT_0)
if (!MyDevFound)//Device extract also set the event 
continue;
GetOverlappedResult(m_hReadHandle,
&ReadOverlapped,
&nBytesRead,
TRUE);//you can also set the last parameter False
if (nBytesRead != 0)
m_strTemp = ReadReportBuffer;
m_strLog.Format(_T("Read the Report Data Length is %d.(%02d:%02d:%02d)"),
nBytesRead, sysTime.wHour, sysTime.wMinute, sysTime.wSecond);
m_strLog += m_strTemp;
Display_Info::SendEvent(m_strLog);
//Display Receive Data
pDlg->DisplayDataHex(ReadReportBuffer, nBytesRead);
why nBytesRead value = 64?

Answer 1

and if you open a non overlapped handle and send synchronous IO, how many bytes are returned? the code you posted was too much of a snippet, post the entirety of the function so that we can see what is going on.
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