SafeWaitHandle クラスとは何？わかりやすく解説 Weblio辞書

.NET Framework クラスライブラリリファレンス

索引トップ用語の索引ランキング

SafeWaitHandle クラス

メモ : このクラスは、.NET Framework version 2.0 で新しく追加されたものです。

待機ハンドルのラッパークラスを表します。このクラスは継承できません。

名前空間: Microsoft.Win32.SafeHandles
アセンブリ: mscorlib (mscorlib.dll 内)
構文

Visual Basic (宣言)

Public NotInheritable Class
 SafeWaitHandle
    Inherits SafeHandleZeroOrMinusOneIsInvalid

Visual Basic (使用法)

Dim instance As SafeWaitHandle

public sealed class SafeWaitHandle : SafeHandleZeroOrMinusOneIsInvalid

C++

public ref class SafeWaitHandle sealed : public
 SafeHandleZeroOrMinusOneIsInvalid

public final class SafeWaitHandle extends SafeHandleZeroOrMinusOneIsInvalid

JScript

public final class SafeWaitHandle extends
 SafeHandleZeroOrMinusOneIsInvalid

解説

SafeWaitHandle クラスは、System.Threading.WaitHandle クラスによって使用されます。これは Win32 ミューテックスおよび自動および手動リセットイベントのラッパーです。

使用例

相互運用機能を使って、SafeWaitHandle クラスおよび CreateMutex アンマネージ関数を使用してミューテックスを作成する方法のコード例を次に示します。

Visual Basic

Imports System
Imports Microsoft.Win32.SafeHandles
Imports System.Runtime.InteropServices

Class SafeHandlesExample


    Shared Sub Main()
        Dim uMutex As New
 UnmanagedMutex("YourCompanyName_SafeHandlesExample_MUTEX")

        Try

            uMutex.Create()
            Console.WriteLine("Mutex created. Press Enter to release
 it.")
            Console.ReadLine()


        Catch e As Exception
            Console.WriteLine(e)
        Finally
            uMutex.Release()
            Console.WriteLine("Mutex Released.")
        End Try

        Console.ReadLine()

    End Sub
End Class


Class UnmanagedMutex



    ' Use interop to call the CreateMutex function.
    ' For more information about CreateMutex,
    ' see the unmanaged MSDN reference library.
    <DllImport("kernel32.dll")> _
    Shared Function CreateMutex(ByVal
 lpMutexAttributes As IntPtr, ByVal bInitialOwner
 As Boolean, ByVal lpName As String) As SafeWaitHandle

    End Function



    ' Use interop to call the ReleaseMutex function.
    ' For more information about ReleaseMutex,
    ' see the unmanaged MSDN reference library.
    <DllImport("kernel32.dll")> _
    Public Shared Function
 ReleaseMutex(ByVal hMutex As SafeWaitHandle)
 As Boolean

    End Function



    Private handleValue As SafeWaitHandle =
 Nothing
    Private mutexAttrValue As IntPtr = IntPtr.Zero
    Private nameValue As String
 = Nothing


    Public Sub New(ByVal
 Name As String)
        nameValue = Name

    End Sub



    Public Sub Create()
        If nameValue Is Nothing
 AndAlso nameValue.Length = 0 Then
            Throw New ArgumentNullException("nameValue")
        End If

        handleValue = CreateMutex(mutexAttrValue, True, nameValue)

        ' If the handle is invalid,
        ' get the last Win32 error 
        ' and throw a Win32Exception.
        If handleValue.IsInvalid Then
            Marshal.ThrowExceptionForHR(Marshal.GetLastWin32Error())
        End If

    End Sub


    Public ReadOnly Property
 Handle() As SafeWaitHandle
        Get
            ' If the handle is valid,
            ' return it.
            If Not handleValue.IsInvalid Then
                Return handleValue
            Else
                Return Nothing
            End If
        End Get
    End Property


    Public ReadOnly Property
 Name() As String
        Get
            Return nameValue
        End Get
    End Property



    Public Sub Release()
        ReleaseMutex(handleValue)

    End Sub
End Class

using System;
using Microsoft.Win32.SafeHandles;
using System.Runtime.InteropServices;


class SafeHandlesExample
{

    static void Main()
    {
        UnmanagedMutex uMutex = new UnmanagedMutex("YourCompanyName_SafeHandlesExample_MUTEX");

        try
        {

            uMutex.Create();
            Console.WriteLine("Mutex created. Press Enter to release it.");
            Console.ReadLine();


        }
        catch (Exception e)
        {
            Console.WriteLine(e);
        }
        finally
        {
            uMutex.Release();
            Console.WriteLine("Mutex Released.");
        }

        Console.ReadLine();


    }
}

class UnmanagedMutex 
{


    // Use interop to call the CreateMutex function.
    // For more information about CreateMutex,
    // see the unmanaged MSDN reference library.
    [DllImport("kernel32.dll")]
    static extern SafeWaitHandle CreateMutex(IntPtr lpMutexAttributes,
 bool bInitialOwner,
   string lpName);


    // Use interop to call the ReleaseMutex function.
    // For more information about ReleaseMutex,
    // see the unmanaged MSDN reference library.
    [DllImport("kernel32.dll")]
    public static extern bool
 ReleaseMutex(SafeWaitHandle hMutex);



    private SafeWaitHandle handleValue = null;
    private IntPtr mutexAttrValue = IntPtr.Zero;
    private string nameValue = null;

    public UnmanagedMutex(string Name)
    {
        nameValue = Name;
    }


    public void Create()
    {
        if (nameValue == null && nameValue.Length
 == 0)
        {
            throw new ArgumentNullException("nameValue");
        }

        handleValue = CreateMutex(mutexAttrValue,
                                        true, nameValue);

        // If the handle is invalid,
        // get the last Win32 error 
        // and throw a Win32Exception.
        if (handleValue.IsInvalid)
        {
            Marshal.ThrowExceptionForHR(Marshal.GetLastWin32Error());
        }
    }

    public SafeWaitHandle Handle
    {
        get
        {
            // If the handle is valid,
            // return it.
            if (!handleValue.IsInvalid)
            {
                return handleValue;
            }
            else
            {
                return null;
            }
        }

    }

    public string Name
    {
        get
        {
            return nameValue;
        }

    }


    public void Release()
    {
        ReleaseMutex(handleValue);
    }

}

継承階層

System.Object
   System.Runtime.ConstrainedExecution.CriticalFinalizerObject
     System.Runtime.InteropServices.SafeHandle
       Microsoft.Win32.SafeHandles.SafeHandleZeroOrMinusOneIsInvalid
        Microsoft.Win32.SafeHandles.SafeWaitHandle

スレッドセーフ

この型の public static (Visual Basic では Shared) メンバはすべて、スレッドセーフです。インスタンスメンバの場合は、スレッドセーフであるとは限りません。