Interlocked.Exchange 方法

定义

命名空间:

System.Threading

程序集:

System.Threading.dll

将变量设置为指定值作为原子操作。

重载

Exchange(UInt32, UInt32)	将 32 位无符号整数设置为指定值，并将原始值作为原子操作返回。
Exchange(Single, Single)	将单精度浮点数设置为指定值，并将原始值作为原子操作返回。
Exchange(UIntPtr, UIntPtr)	将特定于平台的句柄或指针设置为指定值，并将原始值作为原子操作返回。
Exchange(UInt64, UInt64)	将 64 位无符号整数设置为指定值，并将原始值作为原子操作返回。
Exchange(IntPtr, IntPtr)	将特定于平台的句柄或指针设置为指定值，并将原始值作为原子操作返回。
Exchange(Int64, Int64)	将 64 位有符号整数设置为指定值，并将原始值作为原子操作返回。
Exchange(Int32, Int32)	将 32 位有符号整数设置为指定值，并将原始值作为原子操作返回。
Exchange(Double, Double)	将双精度浮点数设置为指定值，并将原始值作为原子操作返回。
Exchange(Object, Object)	将对象设置为指定的值，并将对原始对象的引用作为原子操作返回。
Exchange<T>(T, T)	将指定类型的变量 T 设置为指定值，并将原始值作为原子操作返回。

Exchange(UInt32, UInt32)

Source:

Interlocked.cs

重要

此 API 不符合 CLS。

将 32 位无符号整数设置为指定值，并将原始值作为原子操作返回。

public:
 static System::UInt32 Exchange(System::UInt32 % location1, System::UInt32 value);

[System.CLSCompliant(false)]
public static uint Exchange (ref uint location1, uint value);

[<System.CLSCompliant(false)>]
static member Exchange : uint32 * uint32 -> uint32

Public Shared Function Exchange (ByRef location1 As UInteger, value As UInteger) As UInteger

参数

location1

UInt32

要设置为指定值的变量。

value

UInt32

设置 location1 参数的值。

返回

UInt32

location1的原始值。

属性

CLSCompliantAttribute

例外

NullReferenceException

location1 的地址是 null 指针。

Exchange(Single, Single)

Source:

Interlocked.cs

将单精度浮点数设置为指定值，并将原始值作为原子操作返回。

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

参数

location1

Single

要设置为指定值的变量。

value

Single

设置 location1 参数的值。

返回

Single

location1的原始值。

例外

NullReferenceException

location1 的地址是 null 指针。

另请参阅

• 托管线程处理
• 同步基元 概述

Exchange(UIntPtr, UIntPtr)

Source:

Interlocked.cs

重要

此 API 不符合 CLS。

将特定于平台的句柄或指针设置为指定值，并将原始值作为原子操作返回。

public:
 static UIntPtr Exchange(UIntPtr % location1, UIntPtr value);

[System.CLSCompliant(false)]
public static UIntPtr Exchange (ref UIntPtr location1, UIntPtr value);

[<System.CLSCompliant(false)>]
static member Exchange : unativeint * unativeint -> unativeint

Public Shared Function Exchange (ByRef location1 As UIntPtr, value As UIntPtr) As UIntPtr

参数

location1

UIntPtr

unativeint

要设置为指定值的变量。

value

UIntPtr

unativeint

设置 location1 参数的值。

返回

UIntPtr

unativeint

location1的原始值。

属性

CLSCompliantAttribute

例外

NullReferenceException

location1 的地址是 null 指针。

Exchange(UInt64, UInt64)

Source:

Interlocked.cs

重要

此 API 不符合 CLS。

将 64 位无符号整数设置为指定值，并将原始值作为原子操作返回。

public:
 static System::UInt64 Exchange(System::UInt64 % location1, System::UInt64 value);

[System.CLSCompliant(false)]
public static ulong Exchange (ref ulong location1, ulong value);

[<System.CLSCompliant(false)>]
static member Exchange : uint64 * uint64 -> uint64

Public Shared Function Exchange (ByRef location1 As ULong, value As ULong) As ULong

参数

location1

UInt64

要设置为指定值的变量。

value

UInt64

设置 location1 参数的值。

返回

UInt64

location1的原始值。

属性

CLSCompliantAttribute

例外

NullReferenceException

location1 的地址是 null 指针。

Exchange(IntPtr, IntPtr)

Source:

Interlocked.cs

将特定于平台的句柄或指针设置为指定值，并将原始值作为原子操作返回。

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

参数

location1

IntPtr

nativeint

要设置为指定值的变量。

value

IntPtr

nativeint

设置 location1 参数的值。

返回

IntPtr

nativeint

location1的原始值。

例外

NullReferenceException

location1 的地址是 null 指针。

另请参阅

• 托管线程处理
• 同步基元 概述

Exchange(Int64, Int64)

Source:

Interlocked.cs

将 64 位有符号整数设置为指定值，并将原始值作为原子操作返回。

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

参数

location1

Int64

要设置为指定值的变量。

value

Int64

设置 location1 参数的值。

返回

Int64

location1的原始值。

例外

NullReferenceException

location1 的地址是 null 指针。

另请参阅

• 托管线程处理
• 同步基元 概述

Exchange(Int32, Int32)

Source:

Interlocked.cs

将 32 位有符号整数设置为指定值，并将原始值作为原子操作返回。

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

参数

location1

Int32

要设置为指定值的变量。

value

Int32

设置 location1 参数的值。

返回

Int32

location1的原始值。

例外

ArgumentNullException

location1 的地址是 null 指针。

NullReferenceException

location1 的地址是 null 指针。

示例

下面的代码示例演示线程安全资源锁定机制。

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

另请参阅

• 托管线程处理
• 同步基元 概述

Exchange(Double, Double)

Source:

Interlocked.cs

将双精度浮点数设置为指定值，并将原始值作为原子操作返回。

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

参数

location1

Double

要设置为指定值的变量。

value

Double

设置 location1 参数的值。

返回

Double

location1的原始值。

例外

NullReferenceException

location1 的地址是 null 指针。

另请参阅

• 托管线程处理
• 同步基元 概述

Exchange(Object, Object)

Source:

Interlocked.cs

将对象设置为指定的值，并将对原始对象的引用作为原子操作返回。

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

参数

location1

Object

要设置为指定值的变量。

value

Object

设置 location1 参数的值。

返回

Object

location1的原始值。

例外

ArgumentNullException

location1 的地址是 null 指针。

NullReferenceException

location1 的地址是 null 指针。

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方法。 建议调用它，而不是此重载。

另请参阅

• 托管线程处理
• 同步基元 概述

Exchange<T>(T, T)

Source:

Interlocked.CoreCLR.cs

将指定类型的变量 T 设置为指定值，并将原始值作为原子操作返回。

public:
generic <typename T>
 where T : class static T Exchange(T % location1, T value);

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

类型参数

T

要用于 location1 和 value的类型。 此类型必须是引用类型。

参数

location1

T

要设置为指定值的变量。 这是一个引用参数（在 C# 中ref，在 Visual Basic 中 ByRef）。

value

T

设置 location1 参数的值。

返回

T

location1的原始值。

例外

NullReferenceException

location1 的地址是 null 指针。

NotSupportedException

指定了不受支持的 T。

注解

此方法仅支持引用类型。 Int32、Int64、IntPtr、Single和 Double 值类型都有 Exchange 方法的重载，但不支持其他值类型。

注意

此方法重载优于 Exchange(Object, Object) 方法重载，因为后者需要后期绑定访问目标对象。