thread.bas

16 relay output channels and 16 isolated digital input channels LED indicators to show activated

Attribute VB_Name = "ThreadFunction"
Option Explicit
Public Device As clsPCI1755
Public CheckEventThread As clsThreading

Const DataCount As Long = 1024# * 128
Public glDataBuf(DataCount) As Long                  'Fast DO data out buffrer
Public Const glBufferSize As Long = DataCount * 4   'data buffer size in bytes

Public gbStopThread As Boolean

'Thread/process processing API
Public Declare Function TerminateProcess Lib "kernel32" (ByVal hProcess As Long, ByVal uExitCode As Long) As Long
Public Declare Function GetCurrentProcess Lib "kernel32" () As Long
Public Declare Sub ExitThread Lib "kernel32" (ByVal dwExitCode As Long)

Public Function EventThread()
'NOTES:
'1. Do not try to set breakpoint in EvenThread(), this will crash the IDE.
'2. Use "Debug.Print" or something else to trace the thread
'3. Use Visual Bacsic 5.0 to compile this sample
'4. Because multi-thread programming was not be well-supported in Visual Basic,
'   debug this sample may often crash the IDE. So you'd better compile this sample
'   to a executable file and run it if you want to see the result.

  Dim i As Integer
  Dim usEvent As DeviceEvents
  Dim dwStatus As Long, dwRetrieved As Long
  
  gbStopThread = False
  
  'Cyclic check Fast DO events
  Do
  
    'Check events
    Select Case Device.EventCheck(1000)   'Check DO events, Time out = 1 second
    Case deDoHighBufferTransferred
      frmMain.txtBufferChange = "Higher half buffer"
      Device.ClearFlag deDoUnderrun
      
      If (frmMain.chkCyclic.value = 0) Then
        'In non-cyclic mode, data transferring is completted, waiting FIFO empty.
        frmMain.txtFdoAction.Text = "FIFO emptying"
      End If
    
    Case deDoLowBufferTransferred
      frmMain.txtBufferChange = "Lower half buffer"
      Device.ClearFlag deDoUnderrun
    
    Case deDoTerminated
      frmMain.txtFdoAction = "Terminated!"
      gbStopThread = True
      
    Case deDoUnderrun
      frmMain.txtOverrunCount = Val(frmMain.txtOverrunCount.Text) + 1
      Device.ClearFlag deDoUnderrun
       
    Case deNoEvent
      'Time out of check event
      
    End Select
    
    'Get conversion count
    Device.FdoCheck dwStatus, dwRetrieved
    frmMain.txtTransfered = dwRetrieved
    
    If gbStopThread = True Then
      'Disable all events
      Device.EventEnable deDoHighBufferTransferred, False
      Device.EventEnable deDoLowBufferTransferred, False
      Device.EventEnable deDoUnderrun, False
      Device.EventEnable deDoTerminated, False
      
      'Enable controls setting
      frmMain.cmdRun.Enabled = True
      frmMain.cmdExit.Enabled = True
      frmMain.cmdSelectDevice.Enabled = True
      frmMain.cmdStop.Enabled = False
      
      'Terminate this thread
      ExitThread 0#
    End If
  Loop
  
End Function