ReaderWriterLock.ReleaseWriterLock 方法
定義
重要
部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。
減量寫入器鎖定上的鎖定計數。
public:
void ReleaseWriterLock();public void ReleaseWriterLock ();member this.ReleaseWriterLock : unit -> unitPublic Sub ReleaseWriterLock ()例外狀況
執行緒沒有寫入器鎖定。
範例
下列程式碼範例示範如何取得和釋放寫入器鎖定，以及如何處理要求逾時時擲回的例外狀況。
此程式碼是提供給 類別之較大範例的 ReaderWriterLock 一部分。
// The complete code is located in the ReaderWriterLock
// class topic.
using namespace System;
using namespace System::Threading;
public ref class Test
{
public:
// Declaring the ReaderWriterLock at the class level
// makes it visible to all threads.
static ReaderWriterLock^ rwl = gcnew ReaderWriterLock;
// For this example, the shared resource protected by the
// ReaderWriterLock is just an integer.
static int resource = 0;
// The complete code is located in the ReaderWriterLock class topic.
using System;
using System.Threading;
public class Example
{
static ReaderWriterLock rwl = new ReaderWriterLock();
// Define the shared resource protected by the ReaderWriterLock.
static int resource = 0;
' The complete code is located in the ReaderWriterLock class topic.
Imports System.Threading
Public Module Example
Private rwl As New ReaderWriterLock()
' Define the shared resource protected by the ReaderWriterLock.
Private resource As Integer = 0
// Shows how to request and release the writer lock, and
// how to handle time-outs.
static void WriteToResource( Random^ rnd, int timeOut )
{
try
{
rwl->AcquireWriterLock( timeOut );
try
{
// It is safe for this thread to read or write
// from the shared resource.
resource = rnd->Next( 500 );
Display( String::Format( "writes resource value {0}", resource ) );
Interlocked::Increment( writes );
}
finally
{
// Ensure that the lock is released.
rwl->ReleaseWriterLock();
}
}
catch ( ApplicationException^ )
{
// The writer lock request timed out.
Interlocked::Increment( writerTimeouts );
}
}
// Request and release the writer lock, and handle time-outs.
static void WriteToResource(Random rnd, int timeOut)
{
try {
rwl.AcquireWriterLock(timeOut);
try {
// It's safe for this thread to access from the shared resource.
resource = rnd.Next(500);
Display("writes resource value " + resource);
Interlocked.Increment(ref writes);
}
finally {
// Ensure that the lock is released.
rwl.ReleaseWriterLock();
}
}
catch (ApplicationException) {
// The writer lock request timed out.
Interlocked.Increment(ref writerTimeouts);
}
}
' Request and release the writer lock, and handle time-outs.
Sub WriteToResource(rnd As Random, timeOut As Integer)
Try
rwl.AcquireWriterLock(timeOut)
Try
' It's safe for this thread to read or write from the shared resource.
resource = rnd.Next(500)
Display("writes resource value " & resource)
Interlocked.Increment(writes)
Finally
' Ensure that the lock is released.
rwl.ReleaseWriterLock()
End Try
Catch ex As ApplicationException
' The writer lock request timed out.
Interlocked.Increment(writerTimeouts)
End Try
End Sub
};
}
End Module
備註
ReleaseWriterLock 遞減寫入器鎖定計數。 當計數達到零時，就會釋放寫入器鎖定。
注意
如果執行緒有讀取器鎖定或沒有鎖定，則呼叫 ReleaseWriterLock 會 ApplicationException 擲回 。