BUG: Serial Port Driver for WFW 3.11 Sends Extra Byte

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Steps to Reproduce Problem in the 16-Bit Edition of Visual Basic 4

1. Connect two machines using a null modem cable. You must run Windows for Workgroups 3.11 on the machine running Visual Basic.
2. Start a new project in Visual Basic, Form1 is created by default.
3. Add an MSCOMM (MsComm1) control and a command button (Command1) to Form1.
4. Add the following code to the Command1 Click event procedure:

      Sub Command1_Click ()
         Mscomm1.PortOpen = True '(Default name of control has changed in VB4)
         Mscomm1.PortOpen = False
      End Sub
   					

5. Start the Terminal application on the second machine. In Terminal, choose Settings Communications (ALT, S, C) and change the Baud Rate to 9600.
6. From the Run menu in Visual Basic on the first machine, choose Start (ALT, R, S) or press the F5 key to run the program. Click the Command1 button and the machine running Terminal will indicate that a byte has been transmitted from closing the port.

1. Connect two machines using a null modem cable. You must run Windows for Workgroups 3.11 on the machine running Visual Basic.
2. Start a new project in Visual Basic. Form1 is created by default.
3. Add a command button (Command1) to Form1.
4. Add the following Declare statements to the General declarations section of Form1:

      ' Enter each of the following Declare statements on one, single line:
      Declare Function OpenComm Lib "User" (ByVal lpComName As String, ByVal
         wInQueue As Integer, ByVal wOutQueue As Integer) As Integer
      Declare Function CloseComm Lib "User" (ByVal nCid As Integer)
         As Integer
   					

5. Add the following code to the Command1 Click event procedure:

      Sub Command1_Click ()
         Dim id As Integer, success As Integer
         id = OpenComm("COM1", 1024, 128)
         success = CloseComm(id)
      End Sub
   					

6. Start the Terminal application on the second machine. In Terminal, choose Settings Communications (ALT, S, C) and change the Baud Rate to 9600.
7. From the Run menu in Visual Basic on the first machine, choose Start (ALT, R, S) or press the F5 key to run the program. Click the Command1 button and the machine running Terminal will indicate that a byte has been transmitted from closing the port.