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

定义

以原子操作的形式将变量设置为指定的值。Sets a variable to a specified value as an atomic operation.

重载

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

以原子操作的形式,将单精度浮点数设置为指定的值并返回原始值。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)

以原子操作的形式,将对象设置为指定的值并返回对原始对象的引用。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)

以原子操作的形式,将平台特定的句柄或指针设置为指定的值并返回原始值。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)

以原子操作的形式,将双精度浮点数设置为指定的值并返回原始值。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)

以原子操作的形式,将 32 位有符号整数设置为指定的值并返回原始值。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)

以原子操作的形式,将 64 位有符号整数设置为指定的值并返回原始值。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)

将指定类型 T 的变量设置为指定值,并将原始值作为原子操作返回。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)

以原子操作的形式,将单精度浮点数设置为指定的值并返回原始值。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
Public Shared Function Exchange (ByRef location1 As Single, value As Single) As Single

参数

location1
Single Single Single Single

要设置为指定值的变量。The variable to set to the specified value.

value
Single Single Single Single

location1 参数要设置成的值。The value to which the location1 parameter is set.

返回

location1 的原始值。The original value of location1.

异常

location1 的地址为空指针。The address of location1 is a null pointer.

另请参阅

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

以原子操作的形式,将对象设置为指定的值并返回对原始对象的引用。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
Public Shared Function Exchange (ByRef location1 As Object, value As Object) As Object

参数

location1
Object Object Object Object

要设置为指定值的变量。The variable to set to the specified value.

value
Object Object Object Object

location1 参数要设置成的值。The value to which the location1 parameter is set.

返回

location1 的原始值。The original value of location1.

异常

location1 的地址为空指针。The address of location1 is a null pointer.

注解

重要

从 .NET Framework 2.0 开始,Exchange<T>(T, T) 方法重载为引用类型提供类型安全的替代项。Beginning with .NET Framework 2.0, the Exchange<T>(T, T) method overload provides a type-safe alternative for reference types. 我们建议你而不是此重载调用它。We recommend that you call it instead of this overload.

另请参阅

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

以原子操作的形式,将平台特定的句柄或指针设置为指定的值并返回原始值。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
Public Shared Function Exchange (ByRef location1 As IntPtr, value As IntPtr) As IntPtr

参数

location1
IntPtr IntPtr IntPtr IntPtr

要设置为指定值的变量。The variable to set to the specified value.

value
IntPtr IntPtr IntPtr IntPtr

location1 参数要设置成的值。The value to which the location1 parameter is set.

返回

location1 的原始值。The original value of location1.

异常

location1 的地址为空指针。The address of location1 is a null pointer.

另请参阅

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

以原子操作的形式,将双精度浮点数设置为指定的值并返回原始值。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
Public Shared Function Exchange (ByRef location1 As Double, value As Double) As Double

参数

location1
Double Double Double Double

要设置为指定值的变量。The variable to set to the specified value.

value
Double Double Double Double

location1 参数要设置成的值。The value to which the location1 parameter is set.

返回

location1 的原始值。The original value of location1.

异常

location1 的地址为空指针。The address of location1 is a null pointer.

另请参阅

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

以原子操作的形式,将 32 位有符号整数设置为指定的值并返回原始值。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
Public Shared Function Exchange (ByRef location1 As Integer, value As Integer) As Integer

参数

location1
Int32 Int32 Int32 Int32

要设置为指定值的变量。The variable to set to the specified value.

value
Int32 Int32 Int32 Int32

location1 参数要设置成的值。The value to which the location1 parameter is set.

返回

location1 的原始值。The original value of location1.

异常

location1 的地址为空指针。The address of location1 is a null pointer.

示例

下面的代码示例显示了线程安全资源锁定机制。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
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 'Main

        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 
另请参阅

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

以原子操作的形式,将 64 位有符号整数设置为指定的值并返回原始值。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
Public Shared Function Exchange (ByRef location1 As Long, value As Long) As Long

参数

location1
Int64 Int64 Int64 Int64

要设置为指定值的变量。The variable to set to the specified value.

value
Int64 Int64 Int64 Int64

location1 参数要设置成的值。The value to which the location1 parameter is set.

返回

location1 的原始值。The original value of location1.

异常

location1 的地址为空指针。The address of location1 is a null pointer.

另请参阅

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

将指定类型 T 的变量设置为指定值,并将原始值作为原子操作返回。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 (requires 'T : null)
Public Shared Function Exchange(Of T As Class) (ByRef location1 As T, value As T) As T

类型参数

T

要用于 location1value 的类型。The type to be used for location1 and value. 此类型必须是引用类型。This type must be a reference type.

参数

location1
T T T T

要设置为指定值的变量。The variable to set to the specified value. 这是一个引用参数(C# 中为 ref,Visual Basic 中为 ByRef)。This is a reference parameter (ref in C#, ByRef in Visual Basic).

value
T T T T

location1 参数要设置成的值。The value to which the location1 parameter is set.

返回

T T T T

location1 的原始值。The original value of location1.

异常

location1 的地址为空指针。The address of location1 is a null pointer.

注解

此方法仅支持引用类型。This method only supports reference types. 存在一些重载Exchange方法Int32Int64IntPtrSingle,并Double值类型,但其他值类型不支持。There 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.

备注

此方法的重载优于Exchange(Object, Object)方法重载,因为后者需要后期绑定到的目标对象的访问权限。This method overload is preferable to the Exchange(Object, Object) method overload, because the latter requires late-bound access to the destination object .

适用于