Interlocked.Exchange Método

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

Parâmetros

Devoluções

O valor original de location1.

Exceções

Ver também

• de threading gerenciado
• Visão geral das primitivas de sincronização

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

Parâmetros

Devoluções

O valor original de location1.

Exceções

Observações

Ver também

• de threading gerenciado
• Visão geral das primitivas de sincronização

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

Parâmetros

Devoluções

O valor original de location1.

Exceções

Ver também

• de threading gerenciado
• Visão geral das primitivas de sincronização

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

Parâmetros

Devoluções

O valor original de location1.

Exceções

Ver também

• de threading gerenciado
• Visão geral das primitivas de sincronização

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

Parâmetros

Devoluções

O valor original de location1.

Exceções

Exemplos

O seguinte exemplo de código mostra um mecanismo de bloqueio de recursos seguro para threads.

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

Ver também

• de threading gerenciado
• Visão geral das primitivas de sincronização

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

Parâmetros

Devoluções

O valor original de location1.

Exceções

Ver também

• de threading gerenciado
• Visão geral das primitivas de sincronização

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;

[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)

[<System.Runtime.InteropServices.ComVisible(false)>]
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

Parâmetros de Tipo Genérico

Parâmetros

Devoluções

O valor original de location1.

Atributos

ComVisibleAttribute

Exceções