Interlocked.Exchange Interlocked.Exchange Interlocked.Exchange Interlocked.Exchange Method

定義

把變數設定為特定值,成為不可部分完成的作業。Sets a variable to a specified value as an atomic operation.

多載

Exchange(Single, Single) Exchange(Single, Single) Exchange(Single, Single) Exchange(Single, Single)

將單精確度浮點數設定為指定值,然後傳回原始值,成為不可部分完成的作業。Sets a single-precision floating point number to a specified value and returns the original value, as an atomic operation.

Exchange(Object, Object) Exchange(Object, Object) Exchange(Object, Object) Exchange(Object, Object)

將物件設定為指定值,然後傳回原始物件的參考,成為不可部分完成的作業。Sets an object to a specified value and returns a reference to the original object, as an atomic operation.

Exchange(IntPtr, IntPtr) Exchange(IntPtr, IntPtr) Exchange(IntPtr, IntPtr) Exchange(IntPtr, IntPtr)

將平台特定的控制代碼或指標設定為指定值,然後傳回原始值,成為不可部分完成的作業。Sets a platform-specific handle or pointer to a specified value and returns the original value, as an atomic operation.

Exchange(Double, Double) Exchange(Double, Double) Exchange(Double, Double) Exchange(Double, Double)

將雙精確度浮點數設定為指定值,然後傳回原始值,成為不可部分完成的作業。Sets a double-precision floating point number to a specified value and returns the original value, as an atomic operation.

Exchange(Int32, Int32) Exchange(Int32, Int32) Exchange(Int32, Int32) Exchange(Int32, Int32)

將 32 位元帶正負號的整數設定為指定值,然後傳回原始值,成為不可部分完成的作業。Sets a 32-bit signed integer to a specified value and returns the original value, as an atomic operation.

Exchange(Int64, Int64) Exchange(Int64, Int64) Exchange(Int64, Int64) Exchange(Int64, Int64)

將 64 位元帶正負號的整數設定為指定值,然後傳回原始值,成為不可部分完成的作業。Sets a 64-bit signed integer to a specified value and returns the original value, as an atomic operation.

Exchange<T>(T, T) Exchange<T>(T, T) Exchange<T>(T, T) Exchange<T>(T, T)

將指定型別 T 的變數設定為指定值,然後傳回原始值,成為不可部分完成的作業。Sets a variable of the specified type T to a specified value and returns the original value, as an atomic operation.

Exchange(Single, Single) Exchange(Single, Single) Exchange(Single, Single) Exchange(Single, Single)

將單精確度浮點數設定為指定值,然後傳回原始值,成為不可部分完成的作業。Sets a single-precision floating point number to a specified value and returns the original value, as an atomic operation.

public:
 static float Exchange(float % location1, float value);
public static float Exchange (ref float location1, float value);
static member Exchange : single * single -> single
Public Shared Function Exchange (ByRef location1 As Single, value As Single) As Single

參數

location1
Single Single Single Single

要設定為特定值的變數。The variable to set to the specified value.

value
Single Single Single Single

location1 參數要設定的值。The value to which the location1 parameter is set.

傳回

location1 的原始值。The original value of location1.

例外狀況

location1 的位址為 null 指標。The address of location1 is a null pointer.

另請參閱

Exchange(Object, Object) Exchange(Object, Object) Exchange(Object, Object) Exchange(Object, Object)

將物件設定為指定值,然後傳回原始物件的參考,成為不可部分完成的作業。Sets an object to a specified value and returns a reference to the original object, as an atomic operation.

public:
 static System::Object ^ Exchange(System::Object ^ % location1, System::Object ^ value);
public static object Exchange (ref object location1, object value);
static member Exchange : obj * obj -> obj
Public Shared Function Exchange (ByRef location1 As Object, value As Object) As Object

參數

location1
Object Object Object Object

要設定為特定值的變數。The variable to set to the specified value.

value
Object Object Object Object

location1 參數要設定的值。The value to which the location1 parameter is set.

傳回

location1 的原始值。The original value of location1.

例外狀況

location1 的位址為 null 指標。The address of location1 is a null pointer.

備註

重要

從 .NET Framework 2.0 開始,Exchange<T>(T, T) 方法多載會為參考型別提供型別安全的替代方法。Beginning with .NET Framework 2.0, the Exchange<T>(T, T) method overload provides a type-safe alternative for reference types. 我們建議您呼叫它,而不是這個多載。We recommend that you call it instead of this overload.

另請參閱

Exchange(IntPtr, IntPtr) Exchange(IntPtr, IntPtr) Exchange(IntPtr, IntPtr) Exchange(IntPtr, IntPtr)

將平台特定的控制代碼或指標設定為指定值,然後傳回原始值,成為不可部分完成的作業。Sets a platform-specific handle or pointer to a specified value and returns the original value, as an atomic operation.

public:
 static IntPtr Exchange(IntPtr % location1, IntPtr value);
public static IntPtr Exchange (ref IntPtr location1, IntPtr value);
static member Exchange : nativeint * nativeint -> nativeint
Public Shared Function Exchange (ByRef location1 As IntPtr, value As IntPtr) As IntPtr

參數

location1
IntPtr IntPtr IntPtr IntPtr

要設定為特定值的變數。The variable to set to the specified value.

value
IntPtr IntPtr IntPtr IntPtr

location1 參數要設定的值。The value to which the location1 parameter is set.

傳回

location1 的原始值。The original value of location1.

例外狀況

location1 的位址為 null 指標。The address of location1 is a null pointer.

另請參閱

Exchange(Double, Double) Exchange(Double, Double) Exchange(Double, Double) Exchange(Double, Double)

將雙精確度浮點數設定為指定值,然後傳回原始值,成為不可部分完成的作業。Sets a double-precision floating point number to a specified value and returns the original value, as an atomic operation.

public:
 static double Exchange(double % location1, double value);
public static double Exchange (ref double location1, double value);
static member Exchange : double * double -> double
Public Shared Function Exchange (ByRef location1 As Double, value As Double) As Double

參數

location1
Double Double Double Double

要設定為特定值的變數。The variable to set to the specified value.

value
Double Double Double Double

location1 參數要設定的值。The value to which the location1 parameter is set.

傳回

location1 的原始值。The original value of location1.

例外狀況

location1 的位址為 null 指標。The address of location1 is a null pointer.

另請參閱

Exchange(Int32, Int32) Exchange(Int32, Int32) Exchange(Int32, Int32) Exchange(Int32, Int32)

將 32 位元帶正負號的整數設定為指定值,然後傳回原始值,成為不可部分完成的作業。Sets a 32-bit signed integer to a specified value and returns the original value, as an atomic operation.

public:
 static int Exchange(int % location1, int value);
public static int Exchange (ref int location1, int value);
static member Exchange : int * int -> int
Public Shared Function Exchange (ByRef location1 As Integer, value As Integer) As Integer

參數

location1
Int32 Int32 Int32 Int32

要設定為特定值的變數。The variable to set to the specified value.

value
Int32 Int32 Int32 Int32

location1 參數要設定的值。The value to which the location1 parameter is set.

傳回

location1 的原始值。The original value of location1.

例外狀況

location1 的位址為 null 指標。The address of location1 is a null pointer.

範例

下列程式碼範例顯示安全線程資源鎖定機制。The following code example shows a thread-safe resource locking mechanism.

using namespace System;
using namespace System::Threading;

const int numThreads = 10;
const int numThreadIterations = 5;
ref class MyInterlockedExchangeExampleClass
{
public:
   static void MyThreadProc()
   {
      for ( int i = 0; i < numThreadIterations; i++ )
      {
         UseResource();
         
         //Wait 1 second before next attempt.
         Thread::Sleep( 1000 );

      }
   }


private:
   //A simple method that denies reentrancy.
   static bool UseResource()
   {
      
      //0 indicates that the method is not in use.
      if ( 0 == Interlocked::Exchange( usingResource, 1 ) )
      {
         Console::WriteLine( " {0} acquired the lock", Thread::CurrentThread->Name );
         
         //Code to access a resource that is not thread safe would go here.
         //Simulate some work
         Thread::Sleep( 500 );
         Console::WriteLine( " {0} exiting lock", Thread::CurrentThread->Name );
         
         //Release the lock
         Interlocked::Exchange( usingResource, 0 );
         return true;
      }
      else
      {
         Console::WriteLine( " {0} was denied the lock", Thread::CurrentThread->Name );
         return false;
      }
   }


   //0 for false, 1 for true.
   static int usingResource;
};

int main()
{
   Thread^ myThread;
   Random^ rnd = gcnew Random;
   for ( int i = 0; i < numThreads; i++ )
   {
      myThread = gcnew Thread( gcnew ThreadStart( MyInterlockedExchangeExampleClass::MyThreadProc ) );
      myThread->Name = String::Format( "Thread {0}", i + 1 );
      
      //Wait a random amount of time before starting next thread.
      Thread::Sleep( rnd->Next( 0, 1000 ) );
      myThread->Start();

   }
}

using System;
using System.Threading;

namespace InterlockedExchange_Example
{
    class MyInterlockedExchangeExampleClass
    {
        //0 for false, 1 for true.
        private static int usingResource = 0;

        private const int numThreadIterations = 5;
        private const int numThreads = 10;

        static void Main()
        {
            Thread myThread;
            Random rnd = new Random();

            for(int i = 0; i < numThreads; i++)
            {
                myThread = new Thread(new ThreadStart(MyThreadProc));
                myThread.Name = String.Format("Thread{0}", i + 1);
            
                //Wait a random amount of time before starting next thread.
                Thread.Sleep(rnd.Next(0, 1000));
                myThread.Start();
            }
        }

        private static void MyThreadProc()
        {
            for(int i = 0; i < numThreadIterations; i++)
            {
                UseResource();
            
                //Wait 1 second before next attempt.
                Thread.Sleep(1000);
            }
        }

        //A simple method that denies reentrancy.
        static bool UseResource()
        {
            //0 indicates that the method is not in use.
            if(0 == Interlocked.Exchange(ref usingResource, 1))
            {
                Console.WriteLine("{0} acquired the lock", Thread.CurrentThread.Name);
            
                //Code to access a resource that is not thread safe would go here.
            
                //Simulate some work
                Thread.Sleep(500);

                Console.WriteLine("{0} exiting lock", Thread.CurrentThread.Name);
            
                //Release the lock
                Interlocked.Exchange(ref usingResource, 0);
                return true;
            }
            else
            {
                Console.WriteLine("   {0} was denied the lock", Thread.CurrentThread.Name);
                return false;
            }
        }

    }
}  
Imports System.Threading

Namespace InterlockedExchange_Example
    Class MyInterlockedExchangeExampleClass
        '0 for false, 1 for true.
        Private Shared usingResource As Integer = 0

        Private Const numThreadIterations As Integer = 5
        Private Const numThreads As Integer = 10

        <MTAThread> _
        Shared Sub Main()
            Dim myThread As Thread
            Dim rnd As New Random()

            Dim i As Integer
            For i = 0 To numThreads - 1
                myThread = New Thread(AddressOf MyThreadProc)
                myThread.Name = String.Format("Thread{0}", i + 1)

                'Wait a random amount of time before starting next thread.
                Thread.Sleep(rnd.Next(0, 1000))
                myThread.Start()
            Next i
        End Sub

        Private Shared Sub MyThreadProc()
            Dim i As Integer
            For i = 0 To numThreadIterations - 1
                UseResource()

                'Wait 1 second before next attempt.
                Thread.Sleep(1000)
            Next i
        End Sub 

        'A simple method that denies reentrancy.
        Shared Function UseResource() As Boolean
            '0 indicates that the method is not in use.
            If 0 = Interlocked.Exchange(usingResource, 1) Then
                Console.WriteLine("{0} acquired the lock", Thread.CurrentThread.Name)

                'Code to access a resource that is not thread safe would go here.
                'Simulate some work
                Thread.Sleep(500)

                Console.WriteLine("{0} exiting lock", Thread.CurrentThread.Name)

                'Release the lock
                Interlocked.Exchange(usingResource, 0)
                Return True
            Else
                Console.WriteLine("   {0} was denied the lock", Thread.CurrentThread.Name)
                Return False
            End If
        End Function 
    End Class 
End Namespace 
另請參閱

Exchange(Int64, Int64) Exchange(Int64, Int64) Exchange(Int64, Int64) Exchange(Int64, Int64)

將 64 位元帶正負號的整數設定為指定值,然後傳回原始值,成為不可部分完成的作業。Sets a 64-bit signed integer to a specified value and returns the original value, as an atomic operation.

public:
 static long Exchange(long % location1, long value);
public static long Exchange (ref long location1, long value);
static member Exchange : int64 * int64 -> int64
Public Shared Function Exchange (ByRef location1 As Long, value As Long) As Long

參數

location1
Int64 Int64 Int64 Int64

要設定為特定值的變數。The variable to set to the specified value.

value
Int64 Int64 Int64 Int64

location1 參數要設定的值。The value to which the location1 parameter is set.

傳回

location1 的原始值。The original value of location1.

例外狀況

location1 的位址為 null 指標。The address of location1 is a null pointer.

另請參閱

Exchange<T>(T, T) Exchange<T>(T, T) Exchange<T>(T, T) Exchange<T>(T, T)

將指定型別 T 的變數設定為指定值,然後傳回原始值,成為不可部分完成的作業。Sets a variable of the specified type T to a specified value and returns the original value, as an atomic operation.

public:
generic <typename T>
 where T : class static T Exchange(T % location1, T value);
[System.Runtime.InteropServices.ComVisible(false)]
public static T Exchange<T> (ref T location1, T value) where T : class;
static member Exchange : 'T * 'T -> 'T (requires 'T : null)
Public Shared Function Exchange(Of T As Class) (ByRef location1 As T, value As T) As T

類型參數

T

用於 location1value 的型別。The type to be used for location1 and value. 此型別必須是參考型別。This type must be a reference type.

參數

location1
T T T T

要設定為特定值的變數。The variable to set to the specified value. 此為參考參數 (在 C# 中為 ref,在 Visual Basic 中為 ByRef)。This is a reference parameter (ref in C#, ByRef in Visual Basic).

value
T T T T

location1 參數要設定的值。The value to which the location1 parameter is set.

傳回

T T T T

location1 的原始值。The original value of location1.

例外狀況

location1 的位址為 null 指標。The address of location1 is a null pointer.

備註

這個方法只支援參考型別。This method only supports reference types. Int32、 、、Single和實值類型Exchange的方法有多載,但不支援其他實數值型別。 Double IntPtr Int64There are overloads of the Exchange method for the Int32, Int64, IntPtr, Single, and Double value types, but there is no support for other value types.

注意

這個方法多載較Exchange(Object, Object)適合方法多載,因為後者需要對目的地物件進行晚期繫結的存取。This method overload is preferable to the Exchange(Object, Object) method overload, because the latter requires late-bound access to the destination object .

適用於