分割不可能な操作として指定した値を 32 ビット符号付整数として設定し、元の値を返します。
Overloads Public Shared Function Exchange( _
ByRef location1 As Integer, _ ByVal value As Integer _) As Integer
[C#]
public static int Exchange( ref intlocation1,intvalue);
[C++]
public: static int Exchange(int* location1,intvalue);
[JScript]
public static function Exchange(
location1 : int,value : int) : int;
パラメータ
- location1
指定した値に設定する変数。 - value
location1 パラメータに設定される値。
戻り値
location1 の元の値。
使用例
[Visual Basic, C#, C++] スレッド セーフなリソース ロック機構の例を次に示します。
Imports System
Imports System.Threading
Namespace InterlockedExchange_Example
Class MyInterlockedExchangeExampleClass
'0 for false, 1 for true.
Private Shared usingResource As Integer = 0
Private Shared currentMso As [Object]
Private Shared globalMso As New [Object]()
Private Const numThreadIterations As Integer = 5
Private Const numThreads As Integer = 10
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 'MyThreadProc
'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 'UseResource
End Class 'MyInterlockedExchangeExampleClass
End Namespace 'InterlockedExchange_Example
[C#]
using System;
using System.Threading;
namespace InterlockedExchange_Example
{
class MyInterlockedExchangeExampleClass
{
//0 for false, 1 for true.
private static int usingResource = 0;
private static Object currentMso;
private static Object globalMso = new Object();
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;
}
}
}
}
[C++]
#using <mscorlib.dll>
using namespace System;
using namespace System::Threading;
const int numThreads = 10;
const int numThreadIterations = 5;
__gc 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(S" {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(S" {0} exiting lock", Thread::CurrentThread->Name);
//Release the lock
Interlocked::Exchange( &usingResource, 0);
return true;
}
else
{
Console::WriteLine(S" {0} was denied the lock", Thread::CurrentThread->Name);
return false;
}
}
private:
//0 for false, 1 for true.
static int usingResource;
static Object* globalMso = new Object();
};
void main()
{
Thread* myThread;
Random* rnd = new Random();
for (int i = 0; i < numThreads; i++)
{
myThread = new Thread(new ThreadStart(0, MyInterlockedExchangeExampleClass::MyThreadProc));
myThread->Name = String::Format(S"Thread {0}", __box(i + 1));
//Wait a random amount of time before starting next thread.
Thread::Sleep(rnd->Next(0, 1000));
myThread->Start();
}
}
[JScript] JScript のサンプルはありません。Visual Basic、C#、および C++ のサンプルを表示するには、このページの左上隅にある言語のフィルタ ボタン .gif)
をクリックします。
必要条件
プラットフォーム: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 ファミリ, .NET Compact Framework - Windows CE .NET, Common Language Infrastructure (CLI) Standard
参照
Interlocked クラス | Interlocked メンバ | System.Threading 名前空間 | Interlocked.Exchange オーバーロードの一覧 | スレッド処理 | Interlocked