Option Explicit

'**********************************************************************

'* S2L2.bas - (Section 2, Lesson 2) RECEIVING AN INTEGER FROM THE

'*                                  TARGET

'*            This is the RTDX Host Client for Section 2, Lesson 2

'*

'* This example receives integer value 5 from the target

'**********************************************************************



'**********************************************************************

' Insert code from Step #3 here - to include RTDX return code contants

'**********************************************************************

Const Success = &H0                     ' Method call is valid

Const Failure = &H80004005              ' Method call failed

Const ENoDataAvailable = &H8003001E     ' No data was available.

                                        ' However, more data may be

                                        ' available in the future.

Const EEndOfLogFile = &H80030002        ' No data was available

                                        ' The end of the log file has

                                        ' been reached.



Sub main()

    '******************************************************************

    ' Insert code from Step #4 here - to declare a variable of type

    '                                 Object. This will be used to

    '                                 access the methods of the

    '                                 interface

    '******************************************************************

    Dim rtdx As Object

    

    Dim data As Long

    Dim status As Long



    On Error GoTo Error_Handler

    '******************************************************************

    ' Insert code from Step #5 here - to create an instance of the RTDX

    '                                 COM Object

    '******************************************************************

    Set rtdx = CreateObject("RTDX")



    '******************************************************************    

    ' Insert code from Step #6 here - to open channel ochan for reading

    '******************************************************************

    status = rtdx.Open("ochan", "R")



    If status <> Success Then

        Debug.Print "Opening of channel ochan failed"

        Goto Error_Handler

    End If



    Do

        ' *************************************************************

        ' Insert code from Step #7 here - to read a 32-bit integer from

        '                                 the target

        '**************************************************************

        status = rtdx.ReadI4(data)

 

        Select Case (status)

            Case Success

                If status = Success Then

                    Debug.Print "Value " & _

                                data & _

                                " was received from the target"

                End If

            Case ENoDataAvailable

                Debug.Print "No data is currently available"

            Case EEndOfLogFile

                Debug.Print "End of log file has been detected"

            Case Failure

                Debug.Print "ReadI4 returned failure"

                Exit Do

            Case Else

                Debug.Print "Unknown return code"

                Exit Do

        End Select

    Loop Until status = EEndOfLogFile



    '******************************************************************

    ' Insert code from Step #8 here - to close the channel

    '******************************************************************

    status = rtdx.Close()



    '****************************************************************** 

    ' Insert code from Step #9 here - to release reference

    '                                 to RTDX COM Object

    '******************************************************************

    Set rtdx = Nothing

    

    Exit Sub



Error_Handler:

Debug.Print "Error in COM method call"

Set rtdx = Nothing



End Sub