ReaderWriterLock.ReleaseReaderLock 方法

定义

减少锁计数。Decrements the lock count.

public:
 void ReleaseReaderLock();
public void ReleaseReaderLock ();
member this.ReleaseReaderLock : unit -> unit
Public Sub ReleaseReaderLock ()

例外

线程没有读线程锁或写线程锁。The thread does not have any reader or writer locks.

示例

下面的代码示例演示如何获取和释放读取器锁,以及如何处理请求超时时引发的异常。The following code example shows how to acquire and release a reader lock, and how to handle the exception thrown when a request times out.

此代码是为 ReaderWriterLock 类提供的更大示例的一部分。This code is part of a larger example provided for the ReaderWriterLock class.

// 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 a reader lock, and
// how to handle time-outs.
static void ReadFromResource( int timeOut )
{
   try
   {
      rwl->AcquireReaderLock( timeOut );
      try
      {

         // It is safe for this thread to read from
         // the shared resource.
         Display( String::Format( "reads resource value {0}", resource ) );
         Interlocked::Increment( reads );
      }
      finally
      {

         // Ensure that the lock is released.
         rwl->ReleaseReaderLock();
      }

   }
   catch ( ApplicationException^ )
   {

      // The reader lock request timed out.
      Interlocked::Increment( readerTimeouts );
   }

}


// Request and release a reader lock, and handle time-outs.
static void ReadFromResource(int timeOut)
{
   try {
      rwl.AcquireReaderLock(timeOut);
      try {
         // It is safe for this thread to read from the shared resource.
         Display("reads resource value " + resource);
         Interlocked.Increment(ref reads);
      }
      finally {
         // Ensure that the lock is released.
         rwl.ReleaseReaderLock();
      }
   }
   catch (ApplicationException) {
      // The reader lock request timed out.
      Interlocked.Increment(ref readerTimeouts);
   }
}
' Request and release a reader lock, and handle time-outs.
Sub ReadFromResource(timeOut As Integer)
   Try
      rwl.AcquireReaderLock(timeOut)
      Try
         ' It's safe for this thread to read from the shared resource.
         Display("reads resource value " & resource)
         Interlocked.Increment(reads)
      Finally
         ' Ensure that the lock is released.
         rwl.ReleaseReaderLock()
      End Try
   Catch ex As ApplicationException
      ' The reader lock request timed out.
      Interlocked.Increment(readerTimeouts)
   End Try
End Sub
};


}
End Module

注解

ReleaseReaderLock 递减锁计数。ReleaseReaderLock decrements the lock count. 如果计数为零,则释放锁。When the count reaches zero, the lock is released.

备注

如果线程具有写入器锁,则调用 ReleaseReaderLock 与调用 ReleaseWriterLock具有相同的效果。If a thread has the writer lock, calling ReleaseReaderLock has the same effect as calling ReleaseWriterLock. 如果线程没有锁,调用 ReleaseReaderLock 将引发 ApplicationExceptionIf a thread has no locks, calling ReleaseReaderLock throws an ApplicationException.

适用于

另请参阅