B4J Question Connexion to VideoProjector in 3 continuous steps

[CR95]

I would like to connect a VP from a NON UI B4J program.
Hardware/network initialization flow is as follows :
- socket Initialize
- socket connect
- wait for socket connected
- send specific pattern to VP
- wait for VP response.

I group all the code in a subroutine as the VP frequently disconnects and my subroutine is used to reconnect from different places in my main program

Private Sub ConnectToVP
    If FluxVP.IsInitialized  Then
        FluxVP.Close
    End If
    If Socket.IsInitialized  Then
        Socket.Close
    End If
    Log("Initialise le socket pour communiquer avec l'EPSON")
    Socket.Initialize("SocketVP")
    Socket.Connect(IPEpson,PortEpson,0)            ' No TimeOut
    Wait For SocketVP_Connected(ConnexionOK As Boolean)

'    Revient ici au retour de l'initialisation de la connexion avec l'EPSON
    If ConnexionOK = True Then   
        Log("Connect initial EPSON Sucessful")
        FluxVP.Initialize(Socket.InputStream, Socket.OutputStream, "FluxVP")
    Else
        Log("Connection EPSON failed")
        Return     
    End If
'    Initialise le VP EPSON avec une pattern de démarrage
'    Pattern(string) = ESC/VP.net<DLE><ETX><NUL><NUL><NUL><NUL>
    Dim StartPattern = "4553432F56502E6E6574100300000000" As String
    Log("Envoie la Pattern de démarrage au VP")
    Dim Buffer() As Byte   
    Buffer = BConv.HexToBytes(StartPattern)
    FluxVP.Write(Buffer)
'
    Wait For FluxVP_NewData (Buffer() As Byte)
    Dim RetourVP As String
    Dim MessRetour As String = "Retour du VP après envoi pattern: "
    RetourVP = BytesToString(Buffer, 0, Buffer.Length, "ASCII")
    If RetourVP.StartsWith("ESC/VP.net") Then
        VPEpsonOK = 1    ' Connecté
        Log(MessRetour & "OK")
    Else
        VPEpsonOK = 0    ' NON Connecté
        Log(MessRetour & "Retour VP pas conforme")
    End If
    Return     
End Sub

First question : I call the subroutine by ConnectToVP and it works BUT control returns to main program just after

Wait For SocketVP_Connected(ConnexionOK As Boolean)

I did not arrive to write a "Wait For .... complete.... "
I get a syntax error
How to keep control in my subroutine because my main program cannot continue execution before the 3 steps of the whole connexion to the VP ?

Second question :
If I modify the subroutine in a "resumable sub" by
- changing its name : Private Sub ConnectToVP As ResumableSub
- adding True or False after each Return
- changing call in main main program by "Wait For (ConnectToVP) Complete (Result As Boolean)"
I got the error : StartMessageLoop is missing.
I made several trials but I did not find where and how I should add this instruction ?

Third question :
How could it be possible to add a timeout test on the whole subroutine if VP never responds ?

Thanks for your help

 

[Erel]

1) [B4X] Resumable subs that return values (ResumableSub)
2)

Sub AppStart(...)
 Start
 StartMessageLoop
End Sub

Sub Start
 'Do whatever you like
End Sub

3) There all kinds of ways to implement a timeout. Why are you setting the timeout parameter to 0?
One possible and simple implementation:

Sub Start
 Do While True
 MakeConnection
 Sleep(10000)
 Do While  FlagThatTellsUsThatThereIsAConnection = True
   Sleep(10000)
 Loop
'close everything and prepare for new connection
Loop

 

[CR95]

Thanks Erel
Question 1 : I follow your recommendation BUT I get a compilation syntax error when I use

    Wait For SocketVP_Connected (ConnexionOK As Boolean) completed (Return As Boolean)

Question 2 : My subroutine has several exits. Do I have to add "StopMessageLoop" after every "Return" ?

Have a good day

 

[Erel]

The syntax is wrong.

[B4X] Resumable subs that return values (ResumableSub)