AbandonedMutexException Kelas

Definisi

Ruang nama:

System.Threading

Rakitan:

netstandard.dll, System.Threading.dll

Sumber:

AbandonedMutexException.cs

Pengecualian yang dilemparkan ketika satu utas memperoleh objek yang telah ditinggalkan utas Mutex lain dengan keluar tanpa melepaskannya.

public ref class AbandonedMutexException : SystemException

public class AbandonedMutexException : SystemException

type AbandonedMutexException = class
    inherit SystemException

Public Class AbandonedMutexException
Inherits SystemException

Warisan

Object

Exception

SystemException

AbandonedMutexException

Contoh

Contoh kode berikut menjalankan utas yang meninggalkan lima mutex, menunjukkan efeknya pada WaitOnemetode , WaitAny, dan WaitAll . Nilai MutexIndex properti ditampilkan untuk WaitAny panggilan.

Nota

Panggilan ke WaitAny metode terganggu oleh salah satu mutex yang ditinggalkan. Mutex lain yang ditinggalkan masih dapat menyebabkan dilemparkan AbandonedMutexException dengan metode tunggu berikutnya.

using System;
using System.Threading;

public class Example
{
    private static ManualResetEvent _dummy = new ManualResetEvent(false);

    private static Mutex _orphan1 = new Mutex();
    private static Mutex _orphan2 = new Mutex();
    private static Mutex _orphan3 = new Mutex();
    private static Mutex _orphan4 = new Mutex();
    private static Mutex _orphan5 = new Mutex();

    [MTAThread]
    public static void Main()
    {
        // Start a thread that takes all five mutexes, and then
        // ends without releasing them.
        //
        Thread t = new Thread(new ThreadStart(AbandonMutex));
        t.Start();
        // Make sure the thread is finished.
        t.Join();

        // Wait on one of the abandoned mutexes. The WaitOne returns
        // immediately, because its wait condition is satisfied by
        // the abandoned mutex, but on return it throws
        // AbandonedMutexException.
        try
        {
            _orphan1.WaitOne();
            Console.WriteLine("WaitOne succeeded.");
        }
        catch(AbandonedMutexException ex)
        {
            Console.WriteLine("Exception on return from WaitOne." +
                "\r\n\tMessage: {0}", ex.Message);
        }
        finally
        {
            // Whether or not the exception was thrown, the current
            // thread owns the mutex, and must release it.
            //
            _orphan1.ReleaseMutex();
        }

        // Create an array of wait handles, consisting of one
        // ManualResetEvent and two mutexes, using two more of the
        // abandoned mutexes.
        WaitHandle[] waitFor = {_dummy, _orphan2, _orphan3};

        // WaitAny returns when any of the wait handles in the 
        // array is signaled, so either of the two abandoned mutexes
        // satisfy its wait condition. On returning from the wait,
        // WaitAny throws AbandonedMutexException. The MutexIndex
        // property returns the lower of the two index values for 
        // the abandoned mutexes. Note that the Try block and the
        // Catch block obtain the index in different ways.
        //  
        try
        {
            int index = WaitHandle.WaitAny(waitFor);
            Console.WriteLine("WaitAny succeeded.");

            // The current thread owns the mutex, and must release
            // it.
            Mutex m = waitFor[index] as Mutex;
            if (m != null) m.ReleaseMutex();
        }
        catch(AbandonedMutexException ex)
        {
            Console.WriteLine("Exception on return from WaitAny at index {0}." +
                "\r\n\tMessage: {1}", ex.MutexIndex, ex.Message);

            // Whether or not the exception was thrown, the current
            // thread owns the mutex, and must release it.
            //
            if (ex.Mutex != null) ex.Mutex.ReleaseMutex();
        }

        // Use two more of the abandoned mutexes for the WaitAll call.
        // WaitAll doesn't return until all wait handles are signaled,
        // so the ManualResetEvent must be signaled by calling Set().
        _dummy.Set();
        waitFor[1] = _orphan4;
        waitFor[2] = _orphan5;

        // The signaled event and the two abandoned mutexes satisfy
        // the wait condition for WaitAll, but on return it throws
        // AbandonedMutexException. For WaitAll, the MutexIndex
        // property is always -1 and the Mutex property is always
        // null.
        //  
        try
        {
            WaitHandle.WaitAll(waitFor);
            Console.WriteLine("WaitAll succeeded.");
        }
        catch(AbandonedMutexException ex)
        {
            Console.WriteLine("Exception on return from WaitAll. MutexIndex = {0}." +
                "\r\n\tMessage: {1}", ex.MutexIndex, ex.Message);
        }
        finally
        {
            // Whether or not the exception was thrown, the current
            // thread owns the mutexes, and must release them.
            //
            _orphan4.ReleaseMutex();
            _orphan5.ReleaseMutex();
        }
    }

    [MTAThread]
    public static void AbandonMutex()
    {
        _orphan1.WaitOne();
        _orphan2.WaitOne();
        _orphan3.WaitOne();
        _orphan4.WaitOne();
        _orphan5.WaitOne();
        // Abandon the mutexes by exiting without releasing them.
        Console.WriteLine("Thread exits without releasing the mutexes.");
    }
}

/* This code example produces the following output:

Thread exits without releasing the mutexes.
Exception on return from WaitOne.
        Message: The wait completed due to an abandoned mutex.
Exception on return from WaitAny at index 1.
        Message: The wait completed due to an abandoned mutex.
Exception on return from WaitAll. MutexIndex = -1.
        Message: The wait completed due to an abandoned mutex.
 */

Option Explicit
Imports System.Threading

Public Class Example
    Private Shared _dummy As New ManualResetEvent(False)

    Private Shared _orphan1 As New Mutex()
    Private Shared _orphan2 As New Mutex()
    Private Shared _orphan3 As New Mutex()
    Private Shared _orphan4 As New Mutex()
    Private Shared _orphan5 As New Mutex()

    <MTAThread> _
    Public Shared Sub Main()
        ' Start a thread that takes all five mutexes, and then
        ' ends without releasing them.
        '
        Dim t As New Thread(AddressOf AbandonMutex)
        t.Start()
        ' Make sure the thread is finished.
        t.Join()

        ' Wait on one of the abandoned mutexes. The WaitOne returns
        ' immediately, because its wait condition is satisfied by
        ' the abandoned mutex, but on return it throws
        ' AbandonedMutexException.
        Try
            _orphan1.WaitOne()
            Console.WriteLine("WaitOne succeeded.")
        Catch ex As AbandonedMutexException
            Console.WriteLine("Exception on return from WaitOne." _
                & vbCrLf & vbTab & "Message: " _
                & ex.Message) 
        Finally
            ' Whether or not the exception was thrown, the current
            ' thread owns the mutex, and must release it.
            '
            _orphan1.ReleaseMutex()
        End Try

        ' Create an array of wait handles, consisting of one
        ' ManualResetEvent and two mutexes, using two more of the
        ' abandoned mutexes.
        Dim waitFor(2) As WaitHandle
        waitFor(0) = _dummy
        waitFor(1) = _orphan2
        waitFor(2) = _orphan3

        ' WaitAny returns when any of the wait handles in the 
        ' array is signaled, so either of the two abandoned mutexes
        ' satisfy its wait condition. On returning from the wait,
        ' WaitAny throws AbandonedMutexException. The MutexIndex
        ' property returns the lower of the two index values for 
        ' the abandoned mutexes. Note that the Try block and the
        ' Catch block obtain the index in different ways.
        '  
        Try
            Dim index As Integer = WaitHandle.WaitAny(waitFor)
            Console.WriteLine("WaitAny succeeded.")

            Dim m As Mutex = TryCast(waitFor(index), Mutex)

            ' The current thread owns the mutex, and must release
            ' it.
            If m IsNot Nothing Then m.ReleaseMutex()
        Catch ex As AbandonedMutexException
            Console.WriteLine("Exception on return from WaitAny at index " _
                & ex.MutexIndex & "." _
                & vbCrLf & vbTab & "Message: " _
                & ex.Message) 

            ' Whether or not the exception was thrown, the current
            ' thread owns the mutex, and must release it.
            '
            If ex.Mutex IsNot Nothing Then ex.Mutex.ReleaseMutex()            
        End Try

        ' Use two more of the abandoned mutexes for the WaitAll call.
        ' WaitAll doesn't return until all wait handles are signaled,
        ' so the ManualResetEvent must be signaled by calling Set(). 
        _dummy.Set()
        waitFor(1) = _orphan4
        waitFor(2) = _orphan5

        ' The signaled event and the two abandoned mutexes satisfy
        ' the wait condition for WaitAll, but on return it throws
        ' AbandonedMutexException. For WaitAll, the MutexIndex
        ' property is always -1 and the Mutex property is always
        ' Nothing.
        '  
        Try
            WaitHandle.WaitAll(waitFor)
            Console.WriteLine("WaitAll succeeded.")
        Catch ex As AbandonedMutexException
            Console.WriteLine("Exception on return from WaitAll. MutexIndex = " _
                & ex.MutexIndex & "." _
                & vbCrLf & vbTab & "Message: " _
                & ex.Message) 
        Finally
            ' Whether or not the exception was thrown, the current
            ' thread owns the mutexes, and must release them.
            '
            CType(waitFor(1), Mutex).ReleaseMutex()
            CType(waitFor(2), Mutex).ReleaseMutex()
        End Try
    End Sub

    <MTAThread> _
    Public Shared Sub AbandonMutex()
        _orphan1.WaitOne()
        _orphan2.WaitOne()
        _orphan3.WaitOne()
        _orphan4.WaitOne()
        _orphan5.WaitOne()
        ' Abandon the mutexes by exiting without releasing them.
        Console.WriteLine("Thread exits without releasing the mutexes.")
    End Sub
End Class

' This code example produces the following output:
'
'Thread exits without releasing the mutexes.
'Exception on return from WaitOne.
'        Message: The wait completed due to an abandoned mutex.
'Exception on return from WaitAny at index 1.
'        Message: The wait completed due to an abandoned mutex.
'Exception on return from WaitAll. MutexIndex = -1.
'        Message: The wait completed due to an abandoned mutex.

Keterangan

Ketika utas meninggalkan mutex, pengecualian dilemparkan ke utas berikutnya yang memperoleh mutex. Utas mungkin memperoleh mutex karena sudah menunggu pada mutex atau karena memasuki mutex di lain waktu.

Mutex yang ditinggalkan menunjukkan kesalahan pemrograman yang serius. Ketika utas keluar tanpa melepaskan mutex, struktur data yang dilindungi oleh mutex mungkin tidak dalam keadaan konsisten. Sebelum versi 2.0 dari .NET Framework, masalah seperti itu sulit ditemukan karena tidak ada pengecualian yang dilemparkan jika penantian selesai sebagai akibat dari mutex yang ditinggalkan. Untuk informasi selengkapnya, lihat kelas Mutex.

Utas berikutnya untuk meminta kepemilikan mutex dapat menangani pengecualian ini dan melanjutkan, asalkan integritas struktur data dapat diverifikasi.

Konstruktor

Nama	Deskripsi
AbandonedMutexException()	Menginisialisasi instans baru kelas AbandonedMutexException dengan nilai default.
AbandonedMutexException(Int32, WaitHandle)	Menginisialisasi instans AbandonedMutexException baru kelas dengan indeks tertentu untuk mutex yang ditinggalkan, jika berlaku, dan Mutex objek yang mewakili mutex.
AbandonedMutexException(SerializationInfo, StreamingContext)	Kedaluwarsa. Menginisialisasi instans AbandonedMutexException baru kelas dengan data berseri.
AbandonedMutexException(String, Exception, Int32, WaitHandle)	Menginisialisasi instans AbandonedMutexException baru kelas dengan pesan kesalahan tertentu, pengecualian dalam, indeks untuk mutex yang ditinggalkan, jika berlaku, dan Mutex objek yang mewakili mutex.
AbandonedMutexException(String, Exception)	Menginisialisasi instans AbandonedMutexException baru kelas dengan pesan kesalahan dan pengecualian dalam yang ditentukan.
AbandonedMutexException(String, Int32, WaitHandle)	Menginisialisasi instans AbandonedMutexException baru kelas dengan pesan kesalahan tertentu, indeks mutex yang ditinggalkan, jika berlaku, dan mutex yang ditinggalkan.
AbandonedMutexException(String)	Menginisialisasi instans AbandonedMutexException baru kelas dengan pesan kesalahan tertentu.

Properti

Nama	Deskripsi
Data	Mendapatkan kumpulan pasangan kunci/nilai yang memberikan informasi tambahan yang ditentukan pengguna tentang pengecualian. (Diperoleh dari Exception)
HelpLink	Mendapatkan atau mengatur tautan ke file bantuan yang terkait dengan pengecualian ini. (Diperoleh dari Exception)
HResult	Mendapatkan atau mengatur HRESULT, nilai numerik berkode yang ditetapkan ke pengecualian tertentu. (Diperoleh dari Exception)
InnerException	Mendapatkan instans Exception yang menyebabkan pengecualian saat ini. (Diperoleh dari Exception)
Message	Mendapatkan pesan yang menjelaskan pengecualian saat ini. (Diperoleh dari Exception)
Mutex	Mendapatkan mutex yang ditinggalkan yang menyebabkan pengecualian, jika diketahui.
MutexIndex	Mendapatkan indeks mutex yang ditinggalkan yang menyebabkan pengecualian, jika diketahui.
Source	Mendapatkan atau mengatur nama aplikasi atau objek yang menyebabkan kesalahan. (Diperoleh dari Exception)
StackTrace	Mendapatkan representasi string dari bingkai langsung pada tumpukan panggilan. (Diperoleh dari Exception)
TargetSite	Mendapatkan metode yang melemparkan pengecualian saat ini. (Diperoleh dari Exception)

Metode

Nama	Deskripsi
Equals(Object)	Menentukan apakah objek yang ditentukan sama dengan objek saat ini. (Diperoleh dari Object)
GetBaseException()	Ketika ditimpa di kelas turunan, mengembalikan Exception yang merupakan akar penyebab dari satu atau beberapa pengecualian berikutnya. (Diperoleh dari Exception)
GetHashCode()	Berfungsi sebagai fungsi hash default. (Diperoleh dari Object)
GetObjectData(SerializationInfo, StreamingContext)	Kedaluwarsa. Saat ditimpa di kelas turunan, mengatur SerializationInfo dengan informasi tentang pengecualian. (Diperoleh dari Exception)
GetType()	Mendapatkan jenis runtime instans saat ini. (Diperoleh dari Exception)
MemberwiseClone()	Membuat salinan dangkal dari Objectsaat ini. (Diperoleh dari Object)
ToString()	Membuat dan mengembalikan representasi string dari pengecualian saat ini. (Diperoleh dari Exception)

Acara

Nama	Deskripsi
SerializeObjectState	Kedaluwarsa. Terjadi ketika pengecualian diserialisasikan untuk membuat objek status pengecualian yang berisi data berseri tentang pengecualian. (Diperoleh dari Exception)

Lihat juga

• Mutex
• Mutex