VBA

Public Function CommRead(intPortID As Integer, strData As String, _
    lngSize As Long) As Long

Dim lngStatus As Long
Dim lngRdSize As Long, lngBytesRead As Long
Dim lngRdStatus As Long, strRdBuffer As String * 1024
Dim lngErrorFlags As Long, udtCommStat As COMSTAT

    On Error GoTo Routine_Error

    strData = ""
    lngBytesRead = 0
    DoEvents

    ' Clear any previous errors and get current status.
    lngStatus = ClearCommError(udtPorts(intPortID).lngHandle, lngErrorFlags, _
        udtCommStat)

    If lngStatus = 0 Then
        lngBytesRead = -1
                 Cells(8, 1).Value = lngBytesRead
        lngStatus = SetCommError("CommRead (ClearCommError)")

        GoTo Routine_Exit
    End If