Semaphore.Release Metodo

Definizione

Esce dal semaforo.Exits the semaphore.

Overload

Release()

Esce dal semaforo e restituisce il conteggio precedente.Exits the semaphore and returns the previous count.

Release(Int32)

Esce dal semaforo il numero di volte specificato e restituisce il conteggio precedente.Exits the semaphore a specified number of times and returns the previous count.

Release()

Esce dal semaforo e restituisce il conteggio precedente.Exits the semaphore and returns the previous count.

public:
 int Release();
public int Release ();
member this.Release : unit -> int
Public Function Release () As Integer

Restituisce

Conteggio del semaforo prima della chiamata del metodo Release.The count on the semaphore before the Release method was called.

Eccezioni

Il conteggio del semaforo ha già raggiunto il valore massimo.The semaphore count is already at the maximum value.

Si è verificato un errore Win32 relativo a un semaforo denominato.A Win32 error occurred with a named semaphore.

Il semaforo corrente rappresenta un semaforo di sistema denominato, ma l'utente non dispone di Modify.The current semaphore represents a named system semaphore, but the user does not have Modify.

-oppure--or- Il semaforo corrente rappresenta un semaforo di sistema denominato, ma non è stato aperto con Modify.The current semaphore represents a named system semaphore, but it was not opened with Modify.

Esempi

Nell'esempio di codice seguente viene creato un semaforo con un numero massimo di tre e un conteggio iniziale pari a zero.The following code example creates a semaphore with a maximum count of three and an initial count of zero. L'esempio avvia cinque thread, che bloccano l'attesa del semaforo.The example starts five threads, which block waiting for the semaphore. Il thread principale usa l'overload del metodo Release(Int32) per aumentare il numero di semafori al massimo, consentendo a tre thread di accedere al semaforo.The main thread uses the Release(Int32) method overload to increase the semaphore count to its maximum, allowing three threads to enter the semaphore. Ogni thread usa il metodo Thread.Sleep per attendere un secondo, per simulare il lavoro e quindi chiama l'overload del metodo Release() per rilasciare il semaforo.Each thread uses the Thread.Sleep method to wait for one second, to simulate work, and then calls the Release() method overload to release the semaphore.

Ogni volta che viene rilasciato il semaforo, viene visualizzato il numero di semafori precedente.Each time the semaphore is released, the previous semaphore count is displayed. I messaggi della console tengono traccia dell'uso del semaforo.Console messages track semaphore use. L'intervallo di lavoro simulato viene leggermente aumentato per ogni thread, per semplificare la lettura dell'output.The simulated work interval is increased slightly for each thread, to make the output easier to read.

#using <System.dll>
using namespace System;
using namespace System::Threading;

public ref class Example
{
private:
   // A semaphore that simulates a limited resource pool.
   //
   static Semaphore^ _pool;

   // A padding interval to make the output more orderly.
   static int _padding;

public:
   static void Main()
   {
      // Create a semaphore that can satisfy up to three
      // concurrent requests. Use an initial count of zero,
      // so that the entire semaphore count is initially
      // owned by the main program thread.
      //
      _pool = gcnew Semaphore( 0,3 );
      
      // Create and start five numbered threads.
      //
      for ( int i = 1; i <= 5; i++ )
      {
         Thread^ t = gcnew Thread(
            gcnew ParameterizedThreadStart( Worker ) );
         
         // Start the thread, passing the number.
         //
         t->Start( i );
      }
      
      // Wait for half a second, to allow all the
      // threads to start and to block on the semaphore.
      //
      Thread::Sleep( 500 );
      
      // The main thread starts out holding the entire
      // semaphore count. Calling Release(3) brings the
      // semaphore count back to its maximum value, and
      // allows the waiting threads to enter the semaphore,
      // up to three at a time.
      //
      Console::WriteLine( L"Main thread calls Release(3)." );
      _pool->Release( 3 );

      Console::WriteLine( L"Main thread exits." );
   }

private:
   static void Worker( Object^ num )
   {
      // Each worker thread begins by requesting the
      // semaphore.
      Console::WriteLine( L"Thread {0} begins and waits for the semaphore.", num );
      _pool->WaitOne();
      
      // A padding interval to make the output more orderly.
      int padding = Interlocked::Add( _padding, 100 );

      Console::WriteLine( L"Thread {0} enters the semaphore.", num );
      
      // The thread's "work" consists of sleeping for
      // about a second. Each thread "works" a little
      // longer, just to make the output more orderly.
      //
      Thread::Sleep( 1000 + padding );

      Console::WriteLine( L"Thread {0} releases the semaphore.", num );
      Console::WriteLine( L"Thread {0} previous semaphore count: {1}",
         num, _pool->Release() );
   }
};
using System;
using System.Threading;

public class Example
{
    // A semaphore that simulates a limited resource pool.
    //
    private static Semaphore _pool;

    // A padding interval to make the output more orderly.
    private static int _padding;

    public static void Main()
    {
        // Create a semaphore that can satisfy up to three
        // concurrent requests. Use an initial count of zero,
        // so that the entire semaphore count is initially
        // owned by the main program thread.
        //
        _pool = new Semaphore(0, 3);

        // Create and start five numbered threads. 
        //
        for(int i = 1; i <= 5; i++)
        {
            Thread t = new Thread(new ParameterizedThreadStart(Worker));

            // Start the thread, passing the number.
            //
            t.Start(i);
        }

        // Wait for half a second, to allow all the
        // threads to start and to block on the semaphore.
        //
        Thread.Sleep(500);

        // The main thread starts out holding the entire
        // semaphore count. Calling Release(3) brings the 
        // semaphore count back to its maximum value, and
        // allows the waiting threads to enter the semaphore,
        // up to three at a time.
        //
        Console.WriteLine("Main thread calls Release(3).");
        _pool.Release(3);

        Console.WriteLine("Main thread exits.");
    }

    private static void Worker(object num)
    {
        // Each worker thread begins by requesting the
        // semaphore.
        Console.WriteLine("Thread {0} begins " +
            "and waits for the semaphore.", num);
        _pool.WaitOne();

        // A padding interval to make the output more orderly.
        int padding = Interlocked.Add(ref _padding, 100);

        Console.WriteLine("Thread {0} enters the semaphore.", num);
        
        // The thread's "work" consists of sleeping for 
        // about a second. Each thread "works" a little 
        // longer, just to make the output more orderly.
        //
        Thread.Sleep(1000 + padding);

        Console.WriteLine("Thread {0} releases the semaphore.", num);
        Console.WriteLine("Thread {0} previous semaphore count: {1}",
            num, _pool.Release());
    }
}
Imports System.Threading

Public Class Example

    ' A semaphore that simulates a limited resource pool.
    '
    Private Shared _pool As Semaphore

    ' A padding interval to make the output more orderly.
    Private Shared _padding As Integer

    <MTAThread> _
    Public Shared Sub Main()
        ' Create a semaphore that can satisfy up to three
        ' concurrent requests. Use an initial count of zero,
        ' so that the entire semaphore count is initially
        ' owned by the main program thread.
        '
        _pool = New Semaphore(0, 3)

        ' Create and start five numbered threads. 
        '
        For i As Integer = 1 To 5
            Dim t As New Thread(New ParameterizedThreadStart(AddressOf Worker))
            'Dim t As New Thread(AddressOf Worker)

            ' Start the thread, passing the number.
            '
            t.Start(i)
        Next i

        ' Wait for half a second, to allow all the
        ' threads to start and to block on the semaphore.
        '
        Thread.Sleep(500)

        ' The main thread starts out holding the entire
        ' semaphore count. Calling Release(3) brings the 
        ' semaphore count back to its maximum value, and
        ' allows the waiting threads to enter the semaphore,
        ' up to three at a time.
        '
        Console.WriteLine("Main thread calls Release(3).")
        _pool.Release(3)

        Console.WriteLine("Main thread exits.")
    End Sub

    Private Shared Sub Worker(ByVal num As Object)
        ' Each worker thread begins by requesting the
        ' semaphore.
        Console.WriteLine("Thread {0} begins " _
            & "and waits for the semaphore.", num)
        _pool.WaitOne()

        ' A padding interval to make the output more orderly.
        Dim padding As Integer = Interlocked.Add(_padding, 100)

        Console.WriteLine("Thread {0} enters the semaphore.", num)
        
        ' The thread's "work" consists of sleeping for 
        ' about a second. Each thread "works" a little 
        ' longer, just to make the output more orderly.
        '
        Thread.Sleep(1000 + padding)

        Console.WriteLine("Thread {0} releases the semaphore.", num)
        Console.WriteLine("Thread {0} previous semaphore count: {1}", _
            num, _
            _pool.Release())
    End Sub
End Class

Commenti

I thread usano in genere il metodo WaitOne per accedere al semaforo e in genere usano questo overload del metodo per uscire.Threads typically use the WaitOne method to enter the semaphore, and they typically use this method overload to exit.

Se un SemaphoreFullException viene generato dal metodo Release, non indica necessariamente un problema con il thread chiamante.If a SemaphoreFullException is thrown by the Release method, it does not necessarily indicate a problem with the calling thread. Un errore di programmazione in un altro thread potrebbe avere causato la chiusura del semaforo dal semaforo più volte rispetto all'immissione.A programming error in another thread might have caused that thread to exit the semaphore more times than it entered.

Se l'oggetto Semaphore corrente rappresenta un semaforo di sistema denominato, l'utente deve disporre dei diritti di SemaphoreRights.Modify e il semaforo deve essere stato aperto con diritti di SemaphoreRights.Modify.If the current Semaphore object represents a named system semaphore, the user must have SemaphoreRights.Modify rights and the semaphore must have been opened with SemaphoreRights.Modify rights.

Vedi anche

Release(Int32)

Esce dal semaforo il numero di volte specificato e restituisce il conteggio precedente.Exits the semaphore a specified number of times and returns the previous count.

public:
 int Release(int releaseCount);
public int Release (int releaseCount);
member this.Release : int -> int
Public Function Release (releaseCount As Integer) As Integer

Parametri

releaseCount
Int32

Numero di uscite dal semaforo.The number of times to exit the semaphore.

Restituisce

Conteggio del semaforo prima della chiamata del metodo Release.The count on the semaphore before the Release method was called.

Eccezioni

releaseCount è minore di 1.releaseCount is less than 1.

Il conteggio del semaforo ha già raggiunto il valore massimo.The semaphore count is already at the maximum value.

Si è verificato un errore Win32 relativo a un semaforo denominato.A Win32 error occurred with a named semaphore.

Il semaforo corrente rappresenta un semaforo di sistema denominato, ma l'utente non dispone di diritti Modify.The current semaphore represents a named system semaphore, but the user does not have Modify rights.

-oppure--or- Il semaforo corrente rappresenta un semaforo di sistema denominato, ma non è stato aperto con i diritti Modify.The current semaphore represents a named system semaphore, but it was not opened with Modify rights.

Esempi

Nell'esempio di codice seguente viene creato un semaforo con un numero massimo di tre e un conteggio iniziale pari a zero.The following code example creates a semaphore with a maximum count of three and an initial count of zero. L'esempio avvia cinque thread, che bloccano l'attesa del semaforo.The example starts five threads, which block waiting for the semaphore. Il thread principale usa l'overload del metodo Release(Int32) per aumentare il numero di semafori al massimo, consentendo a tre thread di accedere al semaforo.The main thread uses the Release(Int32) method overload to increase the semaphore count to its maximum, allowing three threads to enter the semaphore. Ogni thread usa il metodo Thread.Sleep per attendere un secondo, per simulare il lavoro e quindi chiama l'overload del metodo Release() per rilasciare il semaforo.Each thread uses the Thread.Sleep method to wait for one second, to simulate work, and then calls the Release() method overload to release the semaphore.

Ogni volta che viene rilasciato il semaforo, viene visualizzato il numero di semafori precedente.Each time the semaphore is released, the previous semaphore count is displayed. I messaggi della console tengono traccia dell'uso del semaforo.Console messages track semaphore use. L'intervallo di lavoro simulato viene leggermente aumentato per ogni thread, per semplificare la lettura dell'output.The simulated work interval is increased slightly for each thread, to make the output easier to read.

#using <System.dll>
using namespace System;
using namespace System::Threading;

public ref class Example
{
private:
   // A semaphore that simulates a limited resource pool.
   //
   static Semaphore^ _pool;

   // A padding interval to make the output more orderly.
   static int _padding;

public:
   static void Main()
   {
      // Create a semaphore that can satisfy up to three
      // concurrent requests. Use an initial count of zero,
      // so that the entire semaphore count is initially
      // owned by the main program thread.
      //
      _pool = gcnew Semaphore( 0,3 );
      
      // Create and start five numbered threads.
      //
      for ( int i = 1; i <= 5; i++ )
      {
         Thread^ t = gcnew Thread(
            gcnew ParameterizedThreadStart( Worker ) );
         
         // Start the thread, passing the number.
         //
         t->Start( i );
      }
      
      // Wait for half a second, to allow all the
      // threads to start and to block on the semaphore.
      //
      Thread::Sleep( 500 );
      
      // The main thread starts out holding the entire
      // semaphore count. Calling Release(3) brings the
      // semaphore count back to its maximum value, and
      // allows the waiting threads to enter the semaphore,
      // up to three at a time.
      //
      Console::WriteLine( L"Main thread calls Release(3)." );
      _pool->Release( 3 );

      Console::WriteLine( L"Main thread exits." );
   }

private:
   static void Worker( Object^ num )
   {
      // Each worker thread begins by requesting the
      // semaphore.
      Console::WriteLine( L"Thread {0} begins and waits for the semaphore.", num );
      _pool->WaitOne();
      
      // A padding interval to make the output more orderly.
      int padding = Interlocked::Add( _padding, 100 );

      Console::WriteLine( L"Thread {0} enters the semaphore.", num );
      
      // The thread's "work" consists of sleeping for
      // about a second. Each thread "works" a little
      // longer, just to make the output more orderly.
      //
      Thread::Sleep( 1000 + padding );

      Console::WriteLine( L"Thread {0} releases the semaphore.", num );
      Console::WriteLine( L"Thread {0} previous semaphore count: {1}",
         num, _pool->Release() );
   }
};
using System;
using System.Threading;

public class Example
{
    // A semaphore that simulates a limited resource pool.
    //
    private static Semaphore _pool;

    // A padding interval to make the output more orderly.
    private static int _padding;

    public static void Main()
    {
        // Create a semaphore that can satisfy up to three
        // concurrent requests. Use an initial count of zero,
        // so that the entire semaphore count is initially
        // owned by the main program thread.
        //
        _pool = new Semaphore(0, 3);

        // Create and start five numbered threads. 
        //
        for(int i = 1; i <= 5; i++)
        {
            Thread t = new Thread(new ParameterizedThreadStart(Worker));

            // Start the thread, passing the number.
            //
            t.Start(i);
        }

        // Wait for half a second, to allow all the
        // threads to start and to block on the semaphore.
        //
        Thread.Sleep(500);

        // The main thread starts out holding the entire
        // semaphore count. Calling Release(3) brings the 
        // semaphore count back to its maximum value, and
        // allows the waiting threads to enter the semaphore,
        // up to three at a time.
        //
        Console.WriteLine("Main thread calls Release(3).");
        _pool.Release(3);

        Console.WriteLine("Main thread exits.");
    }

    private static void Worker(object num)
    {
        // Each worker thread begins by requesting the
        // semaphore.
        Console.WriteLine("Thread {0} begins " +
            "and waits for the semaphore.", num);
        _pool.WaitOne();

        // A padding interval to make the output more orderly.
        int padding = Interlocked.Add(ref _padding, 100);

        Console.WriteLine("Thread {0} enters the semaphore.", num);
        
        // The thread's "work" consists of sleeping for 
        // about a second. Each thread "works" a little 
        // longer, just to make the output more orderly.
        //
        Thread.Sleep(1000 + padding);

        Console.WriteLine("Thread {0} releases the semaphore.", num);
        Console.WriteLine("Thread {0} previous semaphore count: {1}",
            num, _pool.Release());
    }
}
Imports System.Threading

Public Class Example

    ' A semaphore that simulates a limited resource pool.
    '
    Private Shared _pool As Semaphore

    ' A padding interval to make the output more orderly.
    Private Shared _padding As Integer

    <MTAThread> _
    Public Shared Sub Main()
        ' Create a semaphore that can satisfy up to three
        ' concurrent requests. Use an initial count of zero,
        ' so that the entire semaphore count is initially
        ' owned by the main program thread.
        '
        _pool = New Semaphore(0, 3)

        ' Create and start five numbered threads. 
        '
        For i As Integer = 1 To 5
            Dim t As New Thread(New ParameterizedThreadStart(AddressOf Worker))
            'Dim t As New Thread(AddressOf Worker)

            ' Start the thread, passing the number.
            '
            t.Start(i)
        Next i

        ' Wait for half a second, to allow all the
        ' threads to start and to block on the semaphore.
        '
        Thread.Sleep(500)

        ' The main thread starts out holding the entire
        ' semaphore count. Calling Release(3) brings the 
        ' semaphore count back to its maximum value, and
        ' allows the waiting threads to enter the semaphore,
        ' up to three at a time.
        '
        Console.WriteLine("Main thread calls Release(3).")
        _pool.Release(3)

        Console.WriteLine("Main thread exits.")
    End Sub

    Private Shared Sub Worker(ByVal num As Object)
        ' Each worker thread begins by requesting the
        ' semaphore.
        Console.WriteLine("Thread {0} begins " _
            & "and waits for the semaphore.", num)
        _pool.WaitOne()

        ' A padding interval to make the output more orderly.
        Dim padding As Integer = Interlocked.Add(_padding, 100)

        Console.WriteLine("Thread {0} enters the semaphore.", num)
        
        ' The thread's "work" consists of sleeping for 
        ' about a second. Each thread "works" a little 
        ' longer, just to make the output more orderly.
        '
        Thread.Sleep(1000 + padding)

        Console.WriteLine("Thread {0} releases the semaphore.", num)
        Console.WriteLine("Thread {0} previous semaphore count: {1}", _
            num, _
            _pool.Release())
    End Sub
End Class

Commenti

Se un thread ha acceduto più volte al semaforo, questo overload del metodo consente di ripristinare l'intero numero di semafori con una sola chiamata.If a thread has entered the semaphore multiple times, this method overload allows the entire semaphore count to be restored with one call.

Se un SemaphoreFullException viene generato dal metodo Release, non indica necessariamente un problema con il thread chiamante.If a SemaphoreFullException is thrown by the Release method, it does not necessarily indicate a problem with the calling thread. Un errore di programmazione in un altro thread potrebbe avere causato la chiusura del semaforo dal semaforo più volte rispetto all'immissione.A programming error in another thread might have caused that thread to exit the semaphore more times than it entered.

Se l'oggetto Semaphore corrente rappresenta un semaforo di sistema denominato, l'utente deve disporre dei diritti di SemaphoreRights.Modify e il semaforo deve essere stato aperto con diritti di SemaphoreRights.Modify.If the current Semaphore object represents a named system semaphore, the user must have SemaphoreRights.Modify rights and the semaphore must have been opened with SemaphoreRights.Modify rights.

Vedi anche

Si applica a