VB.Net Tutorial/Thread/Mutex

Global Mutex

<source lang="vbnet">Imports System.Threading Module Module1

   Public Class MutexSample
       Shared globalMutex1 As Mutex
       Shared globalMutex2 As Mutex
       Const Counter As Integer = 100
       Shared Event1 As AutoResetEvent = New AutoResetEvent(False)
       Shared Event2 As AutoResetEvent = New AutoResetEvent(False)
       Shared Event3 As AutoResetEvent = New AutoResetEvent(False)
       Shared Event4 As AutoResetEvent = New AutoResetEvent(False)
       Public Sub do1()
           Console.WriteLine("do1 started,  Mutex.WaitAll(Mutex())")
           Dim gMs(1) As Mutex
           gMs(0) = globalMutex1    
           gMs(1) = globalMutex2
           WaitHandle.WaitAll(gMs)
           Thread.Sleep(2000)
           Console.WriteLine("do1 finished, Mutex.WaitAll(Mutex())")
           Event1.Set()
       End Sub
       Public Sub do2()
           Console.WriteLine("do2 started,  globalMutex1.WaitOne( )")
           globalMutex1.WaitOne()   
           Console.WriteLine("do2 finished, globalMutex1.WaitOne( )")
           Event2.Set()  
       End Sub
       Public Sub do3()
           Console.WriteLine("do3 started,  Mutex.WaitAny(Mutex())")
           Dim gMs(1) As Mutex
           gMs(0) = globalMutex1    
           gMs(1) = globalMutex2
           Mutex.WaitAny(gMs)
           Console.WriteLine("do3 finished, Mutex.WaitAny(Mutex())")
           Event3.Set()     
       End Sub
       Public Sub do4() 
           Console.WriteLine("do4 started,  globalMutex2.WaitOne( )")
           globalMutex2.WaitOne()    
           Console.WriteLine("do4 finished, globalMutex2.WaitOne( )")
           Event4.Set()     
       End Sub
       Public Sub Run()     
           Console.WriteLine("MutexSample ...")
           globalMutex1 = New Mutex(True, "MyMutex") 
           globalMutex2 = New Mutex(True)   
           Console.WriteLine(" - Main Owns globalMutex1 and globalMutex2")
           Dim evs(3) As AutoResetEvent
           evs(0) = Event1   
           evs(1) = Event2   
           evs(2) = Event3   
           evs(3) = Event4   
           Dim tm As MutexSample = New MutexSample()
           Dim t1 As Thread = New Thread(New ThreadStart(AddressOf tm.do1))
           Dim t2 As Thread = New Thread(New ThreadStart(AddressOf tm.do2))
           Dim t3 As Thread = New Thread(New ThreadStart(AddressOf tm.do3))
           Dim t4 As Thread = New Thread(New ThreadStart(AddressOf tm.do4))
           t1.Start()     
           t2.Start()     
           t3.Start()     
           t4.Start()     
           Thread.Sleep(2000)
           Console.WriteLine(" - Main releases globalMutex1")
           globalMutex1.ReleaseMutex() 
           Thread.Sleep(1000)
           Console.WriteLine(" - Main releases globalMutex2")
           globalMutex2.ReleaseMutex() 
       End Sub
   End Class 
   Sub main()
       Dim ms As MutexSample = New MutexSample()
       ms.Run()
   End Sub

End Module</source>

MutexSample ...
 - Main Owns globalMutex1 and globalMutex2
do1 started,  Mutex.WaitAll(Mutex())
do2 started,  globalMutex1.WaitOne( )
do3 started,  Mutex.WaitAny(Mutex())
do4 started,  globalMutex2.WaitOne( )
 - Main releases globalMutex1
do3 finished, Mutex.WaitAny(Mutex())
^CTerminate batch job (Y/N)? n