WaitHandle.WaitAll WaitHandle.WaitAll WaitHandle.WaitAll WaitHandle.WaitAll Method

Definition

Waits for all the elements in the specified array to receive a signal.

Overloads

WaitAll(WaitHandle[], TimeSpan, Boolean) WaitAll(WaitHandle[], TimeSpan, Boolean) WaitAll(WaitHandle[], TimeSpan, Boolean) WaitAll(WaitHandle[], TimeSpan, Boolean)

Waits for all the elements in the specified array to receive a signal, using a TimeSpan value to specify the time interval, and specifying whether to exit the synchronization domain before the wait.

WaitAll(WaitHandle[], Int32, Boolean) WaitAll(WaitHandle[], Int32, Boolean) WaitAll(WaitHandle[], Int32, Boolean) WaitAll(WaitHandle[], Int32, Boolean)

Waits for all the elements in the specified array to receive a signal, using an Int32 value to specify the time interval and specifying whether to exit the synchronization domain before the wait.

WaitAll(WaitHandle[], TimeSpan) WaitAll(WaitHandle[], TimeSpan) WaitAll(WaitHandle[], TimeSpan) WaitAll(WaitHandle[], TimeSpan)

Waits for all the elements in the specified array to receive a signal, using a TimeSpan value to specify the time interval.

WaitAll(WaitHandle[], Int32) WaitAll(WaitHandle[], Int32) WaitAll(WaitHandle[], Int32) WaitAll(WaitHandle[], Int32)

Waits for all the elements in the specified array to receive a signal, using an Int32 value to specify the time interval.

WaitAll(WaitHandle[]) WaitAll(WaitHandle[]) WaitAll(WaitHandle[]) WaitAll(WaitHandle[])

Waits for all the elements in the specified array to receive a signal.

WaitAll(WaitHandle[], TimeSpan, Boolean) WaitAll(WaitHandle[], TimeSpan, Boolean) WaitAll(WaitHandle[], TimeSpan, Boolean) WaitAll(WaitHandle[], TimeSpan, Boolean)

Waits for all the elements in the specified array to receive a signal, using a TimeSpan value to specify the time interval, and specifying whether to exit the synchronization domain before the wait.

public:
 static bool WaitAll(cli::array <System::Threading::WaitHandle ^> ^ waitHandles, TimeSpan timeout, bool exitContext);
public static bool WaitAll (System.Threading.WaitHandle[] waitHandles, TimeSpan timeout, bool exitContext);
static member WaitAll : System.Threading.WaitHandle[] * TimeSpan * bool -> bool
Public Shared Function WaitAll (waitHandles As WaitHandle(), timeout As TimeSpan, exitContext As Boolean) As Boolean
Parameters
waitHandles
WaitHandle[]

A WaitHandle array containing the objects for which the current instance will wait. This array cannot contain multiple references to the same object.

timeout
TimeSpan TimeSpan TimeSpan TimeSpan

A TimeSpan that represents the number of milliseconds to wait, or a TimeSpan that represents -1 milliseconds, to wait indefinitely.

exitContext
Boolean Boolean Boolean Boolean

true to exit the synchronization domain for the context before the wait (if in a synchronized context), and reacquire it afterward; otherwise, false.

Returns

true when every element in waitHandles has received a signal; otherwise false.

Exceptions

The waitHandles parameter is null.

-or-

One or more of the objects in the waitHandles array is null.

-or-

waitHandles is an array with no elements and the .NET Framework version is 2.0 or later.

The number of objects in waitHandles is greater than the system permits.

-or-

The STAThreadAttribute attribute is applied to the thread procedure for the current thread, and waitHandles contains more than one element.

waitHandles is an array with no elements and the .NET Framework version is 1.0 or 1.1.

timeout is a negative number other than -1 milliseconds, which represents an infinite time-out.

-or-

timeout is greater than MaxValue.

The wait terminated because a thread exited without releasing a mutex. This exception is not thrown on Windows 98 or Windows Millennium Edition.

The waitHandles array contains a transparent proxy for a WaitHandle in another application domain.

Examples

The following code example shows how to use the thread pool to asynchronously create and write to a group of files. Each write operation is queued as a work item and signals when it is finished. The main thread waits for all the items to signal and then exits.

using namespace System;
using namespace System::IO;
using namespace System::Security::Permissions;
using namespace System::Threading;

// Maintain state to pass to WriteToFile.
ref class State
{
public:
   String^ fileName;
   array<Byte>^byteArray;
   ManualResetEvent^ manualEvent;
   State( String^ fileName, array<Byte>^byteArray, ManualResetEvent^ manualEvent )
      : fileName( fileName ), byteArray( byteArray ), manualEvent( manualEvent )
   {}

};

ref class Writer
{
private:
   static int workItemCount = 0;
   Writer(){}


public:
   static void WriteToFile( Object^ state )
   {
      int workItemNumber = workItemCount;
      Interlocked::Increment( workItemCount );
      Console::WriteLine( "Starting work item {0}.", workItemNumber.ToString() );
      State^ stateInfo = dynamic_cast<State^>(state);
      FileStream^ fileWriter;
      
      // Create and write to the file.
      try
      {
         fileWriter = gcnew FileStream( stateInfo->fileName,FileMode::Create );
         fileWriter->Write( stateInfo->byteArray, 0, stateInfo->byteArray->Length );
      }
      finally
      {
         if ( fileWriter != nullptr )
         {
            fileWriter->Close();
         }
         
         // Signal main() that the work item has finished.
         Console::WriteLine( "Ending work item {0}.", workItemNumber.ToString() );
         stateInfo->manualEvent->Set();
      }

   }

};

int main()
{
   const int numberOfFiles = 5;
   String^ dirName =  "C:\\TestTest";
   String^ fileName;
   array<Byte>^byteArray;
   Random^ randomGenerator = gcnew Random;
   array<ManualResetEvent^>^manualEvents = gcnew array<ManualResetEvent^>(numberOfFiles);
   State^ stateInfo;
   if (  !Directory::Exists( dirName ) )
   {
      Directory::CreateDirectory( dirName );
   }

   
   // Queue the work items that create and write to the files.
   for ( int i = 0; i < numberOfFiles; i++ )
   {
      fileName = String::Concat( dirName,  "\\Test", ((i)).ToString(),  ".dat" );
      
      // Create random data to write to the file.
      byteArray = gcnew array<Byte>(1000000);
      randomGenerator->NextBytes( byteArray );
      manualEvents[ i ] = gcnew ManualResetEvent( false );
      stateInfo = gcnew State( fileName,byteArray,manualEvents[ i ] );
      ThreadPool::QueueUserWorkItem( gcnew WaitCallback( &Writer::WriteToFile ), stateInfo );

   }
   
   // Since ThreadPool threads are background threads, 
   // wait for the work items to signal before exiting.
   if ( WaitHandle::WaitAll( manualEvents, TimeSpan(0,0,5), false ) )
   {
      Console::WriteLine( "Files written - main exiting." );
   }
   else
   {
      
      // The wait operation times out.
      Console::WriteLine( "Error writing files - main exiting." );
   }
}

using System;
using System.IO;
using System.Security.Permissions;
using System.Threading;

class Test
{
    static void Main()
    {
        const int numberOfFiles = 5;
        string dirName = @"C:\TestTest";
        string fileName;

        byte[] byteArray;
        Random randomGenerator = new Random();

        ManualResetEvent[] manualEvents = 
            new ManualResetEvent[numberOfFiles];
        State stateInfo;

        if(!Directory.Exists(dirName))
        {
            Directory.CreateDirectory(dirName);
        }

        // Queue the work items that create and write to the files.
        for(int i = 0; i < numberOfFiles; i++)
        {
            fileName = string.Concat(
                dirName, @"\Test", i.ToString(), ".dat");

            // Create random data to write to the file.
            byteArray = new byte[1000000];
            randomGenerator.NextBytes(byteArray);

            manualEvents[i] = new ManualResetEvent(false);

            stateInfo = 
                new State(fileName, byteArray, manualEvents[i]);

            ThreadPool.QueueUserWorkItem(new WaitCallback(
                Writer.WriteToFile), stateInfo);
        }
    
        // Since ThreadPool threads are background threads, 
        // wait for the work items to signal before exiting.
        if(WaitHandle.WaitAll(
            manualEvents, new TimeSpan(0, 0, 5), false))
        {
            Console.WriteLine("Files written - main exiting.");
        }
        else
        {
            // The wait operation times out.
            Console.WriteLine("Error writing files - main exiting.");
        }
    }
}

// Maintain state to pass to WriteToFile.
class State
{
    public string fileName;
    public byte[] byteArray;
    public ManualResetEvent manualEvent;

    public State(string fileName, byte[] byteArray, 
        ManualResetEvent manualEvent)
    {
        this.fileName = fileName;
        this.byteArray = byteArray;
        this.manualEvent = manualEvent;
    }
}

class Writer
{
    static int workItemCount = 0;
    Writer() {}

    public static void WriteToFile(object state)
    {
        int workItemNumber = workItemCount;
        Interlocked.Increment(ref workItemCount);
        Console.WriteLine("Starting work item {0}.",
            workItemNumber.ToString());
        State stateInfo = (State)state;
        FileStream fileWriter = null;

        // Create and write to the file.
        try
        {
            fileWriter = new FileStream(
                stateInfo.fileName, FileMode.Create);
            fileWriter.Write(stateInfo.byteArray, 
                0, stateInfo.byteArray.Length);
        }
        finally
        {
            if(fileWriter != null)
            {
                fileWriter.Close();
            }

            // Signal Main that the work item has finished.
            Console.WriteLine("Ending work item {0}.", 
                workItemNumber.ToString());
            stateInfo.manualEvent.Set();
        }
    }
}
Imports System
Imports System.IO
Imports System.Security.Permissions
Imports System.Threading

Public Class Test

    ' WaitHandle.WaitAll requires a multithreaded apartment 
    ' when using multiple wait handles.
    <MTAThreadAttribute> _
    Shared Sub Main()
        Const numberOfFiles As Integer = 5
        Dim dirName As String = "C:\TestTest"
        Dim fileName As String 

        Dim byteArray() As Byte 
        Dim randomGenerator As New Random()

        Dim manualEvents(numberOfFiles - 1) As ManualResetEvent
        Dim stateInfo As State 

        If Directory.Exists(dirName) <> True Then
            Directory.CreateDirectory(dirName)
        End If

        ' Queue the work items that create and write to the files.
        For i As Integer = 0 To numberOfFiles - 1
            fileName = String.Concat( _
                dirName, "\Test", i.ToString(), ".dat")

            ' Create random data to write to the file.
            byteArray = New Byte(1000000){}
            randomGenerator.NextBytes(byteArray)

            manualEvents(i) = New ManualResetEvent(false)

            stateInfo = _ 
                New State(fileName, byteArray, manualEvents(i))

            ThreadPool.QueueUserWorkItem(AddressOf _
                Writer.WriteToFile, stateInfo)
        Next i
    
        ' Since ThreadPool threads are background threads, 
        ' wait for the work items to signal before exiting.
        If WaitHandle.WaitAll( _
            manualEvents, New TimeSpan(0, 0, 5), false) = True  Then

            Console.WriteLine("Files written - main exiting.")
        Else
        
            ' The wait operation times out.
            Console.WriteLine("Error writing files - main exiting.")
        End If
    End Sub

End Class
 
' Maintain state to pass to WriteToFile.
Public Class State

    Public fileName As String
    Public byteArray As Byte()
    Public manualEvent As ManualResetEvent

    Sub New(fileName As String, byteArray() As Byte, _
        manualEvent As ManualResetEvent)
    
        Me.fileName = fileName
        Me.byteArray = byteArray
        Me.manualEvent = manualEvent
    End Sub

End Class

Public Class Writer

    Private Sub New()
    End Sub

    Shared workItemCount As Integer = 0

    Shared Sub WriteToFile(state As Object)
        Dim workItemNumber As Integer = workItemCount
        Interlocked.Increment(workItemCount)
        Console.WriteLine("Starting work item {0}.", _
            workItemNumber.ToString())
        Dim stateInfo As State = CType(state, State)
        Dim fileWriter As FileStream = Nothing

        ' Create and write to the file.
        Try
            fileWriter = New FileStream( _
                stateInfo.fileName, FileMode.Create)
            fileWriter.Write(stateInfo.byteArray, _
                0, stateInfo.byteArray.Length)
        Finally
            If Not fileWriter Is Nothing Then
                fileWriter.Close()
            End If

            ' Signal Main that the work item has finished.
            Console.WriteLine("Ending work item {0}.", _
                workItemNumber.ToString())
            stateInfo.manualEvent.Set()
        End Try
    End Sub

End Class

Remarks

If timeout is zero, the method does not block. It tests the state of the wait handles and returns immediately.

AbandonedMutexException is new in the .NET Framework version 2.0. In previous versions, the WaitAll method returns true when a mutex is abandoned. An abandoned mutex often indicates a serious coding error. In the case of a system-wide mutex, it might indicate that an application has been terminated abruptly (for example, by using Windows Task Manager). The exception contains information useful for debugging.

The WaitAll method returns when the wait terminates, which means either all the handles are signaled or a time-out occurs. On some implementations, if more than 64 handles are passed, a NotSupportedException is thrown. If the array contains duplicates, the call will fail.

Note

The WaitAll method is not supported on threads that have STAThreadAttribute.

The maximum value for timeout is Int32.MaxValue.

Notes on Exiting the Context

The exitContext parameter has no effect unless the WaitAll method is called from inside a nondefault managed context. This can happen if your thread is inside a call to an instance of a class derived from ContextBoundObject. Even if you are currently executing a method on a class that is not derived from ContextBoundObject, like String, you can be in a nondefault context if a ContextBoundObject is on your stack in the current application domain.

When your code is executing in a nondefault context, specifying true for exitContext causes the thread to exit the nondefault managed context (that is, to transition to the default context) before executing the WaitAll method. It returns to the original nondefault context after the call to the WaitAll method completes.

This can be useful when the context-bound class has SynchronizationAttribute. In that case, all calls to members of the class are automatically synchronized, and the synchronization domain is the entire body of code for the class. If code in the call stack of a member calls the WaitAll method and specifies true for exitContext, the thread exits the synchronization domain, allowing a thread that is blocked on a call to any member of the object to proceed. When the WaitAll method returns, the thread that made the call must wait to reenter the synchronization domain.

WaitAll(WaitHandle[], Int32, Boolean) WaitAll(WaitHandle[], Int32, Boolean) WaitAll(WaitHandle[], Int32, Boolean) WaitAll(WaitHandle[], Int32, Boolean)

Waits for all the elements in the specified array to receive a signal, using an Int32 value to specify the time interval and specifying whether to exit the synchronization domain before the wait.

public:
 static bool WaitAll(cli::array <System::Threading::WaitHandle ^> ^ waitHandles, int millisecondsTimeout, bool exitContext);
public static bool WaitAll (System.Threading.WaitHandle[] waitHandles, int millisecondsTimeout, bool exitContext);
static member WaitAll : System.Threading.WaitHandle[] * int * bool -> bool
Public Shared Function WaitAll (waitHandles As WaitHandle(), millisecondsTimeout As Integer, exitContext As Boolean) As Boolean
Parameters
waitHandles
WaitHandle[]

A WaitHandle array containing the objects for which the current instance will wait. This array cannot contain multiple references to the same object (duplicates).

millisecondsTimeout
Int32 Int32 Int32 Int32

The number of milliseconds to wait, or Infinite (-1) to wait indefinitely.

exitContext
Boolean Boolean Boolean Boolean

true to exit the synchronization domain for the context before the wait (if in a synchronized context), and reacquire it afterward; otherwise, false.

Returns

true when every element in waitHandles has received a signal; otherwise, false.

Exceptions

The waitHandles parameter is null.

-or-

One or more of the objects in the waitHandles array is null.

-or-

waitHandles is an array with no elements and the .NET Framework version is 2.0 or later.

The number of objects in waitHandles is greater than the system permits.

-or-

The STAThreadAttribute attribute is applied to the thread procedure for the current thread, and waitHandles contains more than one element.

waitHandles is an array with no elements and the .NET Framework version is 1.0 or 1.1.

millisecondsTimeout is a negative number other than -1, which represents an infinite time-out.

The wait completed because a thread exited without releasing a mutex. This exception is not thrown on Windows 98 or Windows Millennium Edition.

The waitHandles array contains a transparent proxy for a WaitHandle in another application domain.

Examples

The following code example shows how to use the thread pool to asynchronously create and write to a group of files. Each write operation is queued as a work item and signals when it is finished. The main thread waits for all the items to signal and then exits.

using namespace System;
using namespace System::IO;
using namespace System::Security::Permissions;
using namespace System::Threading;

// Maintain state to pass to WriteToFile.
ref class State
{
public:
   String^ fileName;
   array<Byte>^byteArray;
   ManualResetEvent^ manualEvent;
   State( String^ fileName, array<Byte>^byteArray, ManualResetEvent^ manualEvent )
      : fileName( fileName ), byteArray( byteArray ), manualEvent( manualEvent )
   {}

};

ref class Writer
{
private:
   static int workItemCount = 0;
   Writer(){}


public:
   static void WriteToFile( Object^ state )
   {
      int workItemNumber = workItemCount;
      Interlocked::Increment( workItemCount );
      Console::WriteLine( "Starting work item {0}.", workItemNumber.ToString() );
      State^ stateInfo = dynamic_cast<State^>(state);
      FileStream^ fileWriter;
      
      // Create and write to the file.
      try
      {
         fileWriter = gcnew FileStream( stateInfo->fileName,FileMode::Create );
         fileWriter->Write( stateInfo->byteArray, 0, stateInfo->byteArray->Length );
      }
      finally
      {
         if ( fileWriter != nullptr )
         {
            fileWriter->Close();
         }
         
         // Signal main() that the work item has finished.
         Console::WriteLine( "Ending work item {0}.", workItemNumber.ToString() );
         stateInfo->manualEvent->Set();
      }

   }

};

int main()
{
   const int numberOfFiles = 5;
   String^ dirName =  "C:\\TestTest";
   String^ fileName;
   array<Byte>^byteArray;
   Random^ randomGenerator = gcnew Random;
   array<ManualResetEvent^>^manualEvents = gcnew array<ManualResetEvent^>(numberOfFiles);
   State^ stateInfo;
   if (  !Directory::Exists( dirName ) )
   {
      Directory::CreateDirectory( dirName );
   }

   
   // Queue the work items that create and write to the files.
   for ( int i = 0; i < numberOfFiles; i++ )
   {
      fileName = String::Concat( dirName,  "\\Test", ((i)).ToString(),  ".dat" );
      
      // Create random data to write to the file.
      byteArray = gcnew array<Byte>(1000000);
      randomGenerator->NextBytes( byteArray );
      manualEvents[ i ] = gcnew ManualResetEvent( false );
      stateInfo = gcnew State( fileName,byteArray,manualEvents[ i ] );
      ThreadPool::QueueUserWorkItem( gcnew WaitCallback( &Writer::WriteToFile ), stateInfo );

   }
   
   // Since ThreadPool threads are background threads, 
   // wait for the work items to signal before exiting.
   if ( WaitHandle::WaitAll( manualEvents, 5000, false ) )
   {
      Console::WriteLine( "Files written - main exiting." );
   }
   else
   {
      
      // The wait operation times out.
      Console::WriteLine( "Error writing files - main exiting." );
   }
}

using System;
using System.IO;
using System.Security.Permissions;
using System.Threading;

class Test
{
    static void Main()
    {
        const int numberOfFiles = 5;
        string dirName = @"C:\TestTest";
        string fileName;

        byte[] byteArray;
        Random randomGenerator = new Random();

        ManualResetEvent[] manualEvents = 
            new ManualResetEvent[numberOfFiles];
        State stateInfo;

        if(!Directory.Exists(dirName))
        {
            Directory.CreateDirectory(dirName);
        }

        // Queue the work items that create and write to the files.
        for(int i = 0; i < numberOfFiles; i++)
        {
            fileName = string.Concat(
                dirName, @"\Test", i.ToString(), ".dat");

            // Create random data to write to the file.
            byteArray = new byte[1000000];
            randomGenerator.NextBytes(byteArray);

            manualEvents[i] = new ManualResetEvent(false);

            stateInfo = 
                new State(fileName, byteArray, manualEvents[i]);

            ThreadPool.QueueUserWorkItem(new WaitCallback(
                Writer.WriteToFile), stateInfo);
        }
    
        // Since ThreadPool threads are background threads, 
        // wait for the work items to signal before exiting.
        if(WaitHandle.WaitAll(manualEvents, 5000, false))
        {
            Console.WriteLine("Files written - main exiting.");
        }
        else
        {
            // The wait operation times out.
            Console.WriteLine("Error writing files - main exiting.");
        }
    }
}

// Maintain state to pass to WriteToFile.
class State
{
    public string fileName;
    public byte[] byteArray;
    public ManualResetEvent manualEvent;

    public State(string fileName, byte[] byteArray, 
        ManualResetEvent manualEvent)
    {
        this.fileName = fileName;
        this.byteArray = byteArray;
        this.manualEvent = manualEvent;
    }
}

class Writer
{
    static int workItemCount = 0;
    Writer() {}

    public static void WriteToFile(object state)
    {
        int workItemNumber = workItemCount;
        Interlocked.Increment(ref workItemCount);
        Console.WriteLine("Starting work item {0}.",
            workItemNumber.ToString());
        State stateInfo = (State)state;
        FileStream fileWriter = null;

        // Create and write to the file.
        try
        {
            fileWriter = new FileStream(
                stateInfo.fileName, FileMode.Create);
            fileWriter.Write(stateInfo.byteArray, 
                0, stateInfo.byteArray.Length);
        }
        finally
        {
            if(fileWriter != null)
            {
                fileWriter.Close();
            }

            // Signal Main that the work item has finished.
            Console.WriteLine("Ending work item {0}.", 
                workItemNumber.ToString());
            stateInfo.manualEvent.Set();
        }
    }
}
Imports System
Imports System.IO
Imports System.Security.Permissions
Imports System.Threading

Public Class Test

    ' WaitHandle.WaitAll requires a multithreaded apartment 
    ' when using multiple wait handles.
    <MTAThreadAttribute> _
    Shared Sub Main()
        Const numberOfFiles As Integer = 5
        Dim dirName As String = "C:\TestTest"
        Dim fileName As String 

        Dim byteArray() As Byte 
        Dim randomGenerator As New Random()

        Dim manualEvents(numberOfFiles - 1) As ManualResetEvent
        Dim stateInfo As State 

        If Directory.Exists(dirName) <> True Then
            Directory.CreateDirectory(dirName)
        End If

        ' Queue the work items that create and write to the files.
        For i As Integer = 0 To numberOfFiles - 1
            fileName = String.Concat( _
                dirName, "\Test", i.ToString(), ".dat")

            ' Create random data to write to the file.
            byteArray = New Byte(1000000){}
            randomGenerator.NextBytes(byteArray)

            manualEvents(i) = New ManualResetEvent(false)

            stateInfo = _ 
                New State(fileName, byteArray, manualEvents(i))

            ThreadPool.QueueUserWorkItem(AddressOf _
                Writer.WriteToFile, stateInfo)
        Next i
    
        ' Since ThreadPool threads are background threads, 
        ' wait for the work items to signal before exiting.
        If WaitHandle.WaitAll(manualEvents, 5000, false) = True  Then

            Console.WriteLine("Files written - main exiting.")
        Else
        
            ' The wait operation times out.
            Console.WriteLine("Error writing files - main exiting.")
        End If
    End Sub

End Class
 
' Maintain state to pass to WriteToFile.
Public Class State

    Public fileName As String
    Public byteArray As Byte()
    Public manualEvent As ManualResetEvent

    Sub New(fileName As String, byteArray() As Byte, _
        manualEvent As ManualResetEvent)
    
        Me.fileName = fileName
        Me.byteArray = byteArray
        Me.manualEvent = manualEvent
    End Sub

End Class

Public Class Writer

    Private Sub New()
    End Sub

    Shared workItemCount As Integer = 0

    Shared Sub WriteToFile(state As Object)
        Dim workItemNumber As Integer = workItemCount
        Interlocked.Increment(workItemCount)
        Console.WriteLine("Starting work item {0}.", _
            workItemNumber.ToString())
        Dim stateInfo As State = CType(state, State)
        Dim fileWriter As FileStream = Nothing

        ' Create and write to the file.
        Try
            fileWriter = New FileStream( _
                stateInfo.fileName, FileMode.Create)
            fileWriter.Write(stateInfo.byteArray, _
                0, stateInfo.byteArray.Length)
        Finally
            If Not fileWriter Is Nothing Then
                fileWriter.Close()
            End If

            ' Signal Main that the work item has finished.
            Console.WriteLine("Ending work item {0}.", _
                workItemNumber.ToString())
            stateInfo.manualEvent.Set()
        End Try
    End Sub

End Class

Remarks

If millisecondsTimeout is zero, the method does not block. It tests the state of the wait handles and returns immediately.

AbandonedMutexException is new in the .NET Framework version 2.0. In previous versions, the WaitAll method returns true when a mutex is abandoned. An abandoned mutex often indicates a serious coding error. In the case of a system-wide mutex, it might indicate that an application has been terminated abruptly (for example, by using Windows Task Manager). The exception contains information useful for debugging.

The WaitAll method returns when the wait terminates, which means either when all the handles are signaled or when time-out occurs. On some implementations, if more than 64 handles are passed, a NotSupportedException is thrown. If there are duplicates in the array, the call fails with a DuplicateWaitObjectException.

Note

The WaitAll method is not supported on threads that have STAThreadAttribute.

Notes on Exiting the Context

The exitContext parameter has no effect unless the WaitAll method is called from inside a nondefault managed context. This can happen if your thread is inside a call to an instance of a class derived from ContextBoundObject. Even if you are currently executing a method on a class that is not derived from ContextBoundObject, like String, you can be in a nondefault context if a ContextBoundObject is on your stack in the current application domain.

When your code is executing in a nondefault context, specifying true for exitContext causes the thread to exit the nondefault managed context (that is, to transition to the default context) before executing the WaitAll method. The thread returns to the original nondefault context after the call to the WaitAll method completes.

This can be useful when the context-bound class has the SynchronizationAttribute attribute. In that case, all calls to members of the class are automatically synchronized, and the synchronization domain is the entire body of code for the class. If code in the call stack of a member calls the WaitAll method and specifies true for exitContext, the thread exits the synchronization domain, allowing a thread that is blocked on a call to any member of the object to proceed. When the WaitAll method returns, the thread that made the call must wait to reenter the synchronization domain.

WaitAll(WaitHandle[], TimeSpan) WaitAll(WaitHandle[], TimeSpan) WaitAll(WaitHandle[], TimeSpan) WaitAll(WaitHandle[], TimeSpan)

Waits for all the elements in the specified array to receive a signal, using a TimeSpan value to specify the time interval.

public:
 static bool WaitAll(cli::array <System::Threading::WaitHandle ^> ^ waitHandles, TimeSpan timeout);
public static bool WaitAll (System.Threading.WaitHandle[] waitHandles, TimeSpan timeout);
static member WaitAll : System.Threading.WaitHandle[] * TimeSpan -> bool
Public Shared Function WaitAll (waitHandles As WaitHandle(), timeout As TimeSpan) As Boolean
Parameters
waitHandles
WaitHandle[]

A WaitHandle array containing the objects for which the current instance will wait. This array cannot contain multiple references to the same object.

timeout
TimeSpan TimeSpan TimeSpan TimeSpan

A TimeSpan that represents the number of milliseconds to wait, or a TimeSpan that represents -1 milliseconds, to wait indefinitely.

Returns

true when every element in waitHandles has received a signal; otherwise, false.

Exceptions

The waitHandles parameter is null.

-or-

One or more of the objects in the waitHandles array is null.

-or-

waitHandles is an array with no elements.

In the [.NET for Windows Store apps](http://go.microsoft.com/fwlink/?LinkID=247912) or the [Portable Class Library](~/docs/standard/cross-platform/cross-platform-development-with-the-portable-class-library.md), catch the base class exception, ArgumentException, instead.

The waitHandles array contains elements that are duplicates.

The number of objects in waitHandles is greater than the system permits.

-or-

The STAThreadAttribute attribute is applied to the thread procedure for the current thread, and waitHandles contains more than one element.

timeout is a negative number other than -1 milliseconds, which represents an infinite time-out.

-or-

timeout is greater than MaxValue.

The wait terminated because a thread exited without releasing a mutex. This exception is not thrown on Windows 98 or Windows Millennium Edition.

The waitHandles array contains a transparent proxy for a WaitHandle in another application domain.

Remarks

If timeout is zero, the method does not block. It tests the state of the wait handles and returns immediately.

The WaitAll method returns when the wait terminates, which means either all the handles are signaled or a time-out occurs. On some implementations, if more than 64 handles are passed, a NotSupportedException is thrown. If the array contains duplicates, the call will fail.

Note

The WaitAll method is not supported on threads that have STAThreadAttribute.

The maximum value for timeout is Int32.MaxValue.

Calling this method overload is the same as calling the WaitAll(WaitHandle[], TimeSpan, Boolean) overload and specifying false for exitContext.

WaitAll(WaitHandle[], Int32) WaitAll(WaitHandle[], Int32) WaitAll(WaitHandle[], Int32) WaitAll(WaitHandle[], Int32)

Waits for all the elements in the specified array to receive a signal, using an Int32 value to specify the time interval.

public:
 static bool WaitAll(cli::array <System::Threading::WaitHandle ^> ^ waitHandles, int millisecondsTimeout);
public static bool WaitAll (System.Threading.WaitHandle[] waitHandles, int millisecondsTimeout);
static member WaitAll : System.Threading.WaitHandle[] * int -> bool
Public Shared Function WaitAll (waitHandles As WaitHandle(), millisecondsTimeout As Integer) As Boolean
Parameters
waitHandles
WaitHandle[]

A WaitHandle array containing the objects for which the current instance will wait. This array cannot contain multiple references to the same object (duplicates).

millisecondsTimeout
Int32 Int32 Int32 Int32

The number of milliseconds to wait, or Infinite (-1) to wait indefinitely.

Returns

true when every element in waitHandles has received a signal; otherwise, false.

Exceptions

The waitHandles parameter is null.

-or-

One or more of the objects in the waitHandles array is null.

-or-

waitHandles is an array with no elements.

In the [.NET for Windows Store apps](http://go.microsoft.com/fwlink/?LinkID=247912) or the [Portable Class Library](~/docs/standard/cross-platform/cross-platform-development-with-the-portable-class-library.md), catch the base class exception, ArgumentException, instead.

The waitHandles array contains elements that are duplicates.

The number of objects in waitHandles is greater than the system permits.

-or-

The STAThreadAttribute attribute is applied to the thread procedure for the current thread, and waitHandles contains more than one element.

millisecondsTimeout is a negative number other than -1, which represents an infinite time-out.

The wait completed because a thread exited without releasing a mutex. This exception is not thrown on Windows 98 or Windows Millennium Edition.

The waitHandles array contains a transparent proxy for a WaitHandle in another application domain.

Remarks

If millisecondsTimeout is zero, the method does not block. It tests the state of the wait handles and returns immediately.

The WaitAll method returns when the wait terminates, which means either when all the handles are signaled or when time-out occurs. On some implementations, if more than 64 handles are passed, a NotSupportedException is thrown. If there are duplicates in the array, the call fails with a DuplicateWaitObjectException.

Note

The WaitAll method is not supported on threads that have STAThreadAttribute.

Calling this method overload is the same as calling the WaitAll(WaitHandle[], Int32, Boolean) overload and specifying false for exitContext.

WaitAll(WaitHandle[]) WaitAll(WaitHandle[]) WaitAll(WaitHandle[]) WaitAll(WaitHandle[])

Waits for all the elements in the specified array to receive a signal.

public:
 static bool WaitAll(cli::array <System::Threading::WaitHandle ^> ^ waitHandles);
public static bool WaitAll (System.Threading.WaitHandle[] waitHandles);
static member WaitAll : System.Threading.WaitHandle[] -> bool
Public Shared Function WaitAll (waitHandles As WaitHandle()) As Boolean
Parameters
waitHandles
WaitHandle[]

A WaitHandle array containing the objects for which the current instance will wait. This array cannot contain multiple references to the same object.

Returns

true when every element in waitHandles has received a signal; otherwise the method never returns.

Exceptions

The waitHandles parameter is null. -or-

One or more of the objects in the waitHandles array are null.

-or-

waitHandles is an array with no elements and the .NET Framework version is 2.0 or later.

In the [.NET for Windows Store apps](http://go.microsoft.com/fwlink/?LinkID=247912) or the [Portable Class Library](~/docs/standard/cross-platform/cross-platform-development-with-the-portable-class-library.md), catch the base class exception, ArgumentException, instead.

The waitHandles array contains elements that are duplicates.

The number of objects in waitHandles is greater than the system permits.

-or-

The STAThreadAttribute attribute is applied to the thread procedure for the current thread, and waitHandles contains more than one element.

waitHandles is an array with no elements and the .NET Framework version is 1.0 or 1.1.

The wait terminated because a thread exited without releasing a mutex. This exception is not thrown on Windows 98 or Windows Millennium Edition.

The waitHandles array contains a transparent proxy for a WaitHandle in another application domain.

Examples

The following code example shows how to use the thread pool to asynchronously create and write to a group of files. Each write operation is queued as a work item and signals when it is finished. The main thread waits for all the items to signal and then exits.

using namespace System;
using namespace System::IO;
using namespace System::Security::Permissions;
using namespace System::Threading;

ref class State
{
public:
   String^ fileName;
   array<Byte>^byteArray;
   ManualResetEvent^ manualEvent;
   State( String^ fileName, array<Byte>^byteArray, ManualResetEvent^ manualEvent )
      : fileName( fileName ), byteArray( byteArray ), manualEvent( manualEvent )
   {}

};

ref class Writer
{
private:
   static int workItemCount = 0;
   Writer(){}


public:
   static void WriteToFile( Object^ state )
   {
      int workItemNumber = workItemCount;
      Interlocked::Increment( workItemCount );
      Console::WriteLine( "Starting work item {0}.", workItemNumber.ToString() );
      State^ stateInfo = dynamic_cast<State^>(state);
      FileStream^ fileWriter;
      
      // Create and write to the file.
      try
      {
         fileWriter = gcnew FileStream( stateInfo->fileName,FileMode::Create );
         fileWriter->Write( stateInfo->byteArray, 0, stateInfo->byteArray->Length );
      }
      finally
      {
         if ( fileWriter != nullptr )
         {
            fileWriter->Close();
         }
         
         // Signal main() that the work item has finished.
         Console::WriteLine( "Ending work item {0}.", workItemNumber.ToString() );
         stateInfo->manualEvent->Set();
      }

   }

};

void main()
{
   const int numberOfFiles = 5;
   String^ dirName =  "C:\\TestTest";
   String^ fileName;
   array<Byte>^byteArray;
   Random^ randomGenerator = gcnew Random;
   array<ManualResetEvent^>^manualEvents = gcnew array<ManualResetEvent^>(numberOfFiles);
   State^ stateInfo;
   if (  !Directory::Exists( dirName ) )
   {
      Directory::CreateDirectory( dirName );
   }

   
   // Queue the work items that create and write to the files.
   for ( int i = 0; i < numberOfFiles; i++ )
   {
      fileName = String::Concat( dirName,  "\\Test", ((i)).ToString(),  ".dat" );
      
      // Create random data to write to the file.
      byteArray = gcnew array<Byte>(1000000);
      randomGenerator->NextBytes( byteArray );
      manualEvents[ i ] = gcnew ManualResetEvent( false );
      stateInfo = gcnew State( fileName,byteArray,manualEvents[ i ] );
      ThreadPool::QueueUserWorkItem( gcnew WaitCallback( &Writer::WriteToFile ), stateInfo );

   }
   
   // Since ThreadPool threads are background threads, 
   // wait for the work items to signal before exiting.
   WaitHandle::WaitAll( manualEvents );
   Console::WriteLine( "Files written - main exiting." );
}

using System;
using System.IO;
using System.Security.Permissions;
using System.Threading;

class Test
{
    static void Main()
    {
        const int numberOfFiles = 5;
        string dirName = @"C:\TestTest";
        string fileName;

        byte[] byteArray;
        Random randomGenerator = new Random();

        ManualResetEvent[] manualEvents = 
            new ManualResetEvent[numberOfFiles];
        State stateInfo;

        if(!Directory.Exists(dirName))
        {
            Directory.CreateDirectory(dirName);
        }

        // Queue the work items that create and write to the files.
        for(int i = 0; i < numberOfFiles; i++)
        {
            fileName = string.Concat(
                dirName, @"\Test", i.ToString(), ".dat");

            // Create random data to write to the file.
            byteArray = new byte[1000000];
            randomGenerator.NextBytes(byteArray);

            manualEvents[i] = new ManualResetEvent(false);

            stateInfo = 
                new State(fileName, byteArray, manualEvents[i]);

            ThreadPool.QueueUserWorkItem(new WaitCallback(
                Writer.WriteToFile), stateInfo);
        }
    
        // Since ThreadPool threads are background threads, 
        // wait for the work items to signal before exiting.
        WaitHandle.WaitAll(manualEvents);
        Console.WriteLine("Files written - main exiting.");
    }
}

// Maintain state to pass to WriteToFile.
class State
{
    public string fileName;
    public byte[] byteArray;
    public ManualResetEvent manualEvent;

    public State(string fileName, byte[] byteArray, 
        ManualResetEvent manualEvent)
    {
        this.fileName = fileName;
        this.byteArray = byteArray;
        this.manualEvent = manualEvent;
    }
}

class Writer
{
    static int workItemCount = 0;
    Writer() {}

    public static void WriteToFile(object state)
    {
        int workItemNumber = workItemCount;
        Interlocked.Increment(ref workItemCount);
        Console.WriteLine("Starting work item {0}.",
            workItemNumber.ToString());
        State stateInfo = (State)state;
        FileStream fileWriter = null;

        // Create and write to the file.
        try
        {
            fileWriter = new FileStream(
                stateInfo.fileName, FileMode.Create);
            fileWriter.Write(stateInfo.byteArray, 
                0, stateInfo.byteArray.Length);
        }
        finally
        {
            if(fileWriter != null)
            {
                fileWriter.Close();
            }

            // Signal Main that the work item has finished.
            Console.WriteLine("Ending work item {0}.", 
                workItemNumber.ToString());
            stateInfo.manualEvent.Set();
        }
    }
}
Imports System
Imports System.IO
Imports System.Security.Permissions
Imports System.Threading

Public Class Test

    ' WaitHandle.WaitAll requires a multithreaded apartment 
    ' when using multiple wait handles.
    <MTAThreadAttribute> _
    Shared Sub Main()
        Const numberOfFiles As Integer = 5
        Dim dirName As String = "C:\TestTest"
        Dim fileName As String 

        Dim byteArray() As Byte 
        Dim randomGenerator As New Random()

        Dim manualEvents(numberOfFiles - 1) As ManualResetEvent
        Dim stateInfo As State 

        If Directory.Exists(dirName) <> True Then
            Directory.CreateDirectory(dirName)
        End If

        ' Queue the work items that create and write to the files.
        For i As Integer = 0 To numberOfFiles - 1
            fileName = String.Concat( _
                dirName, "\Test", i.ToString(), ".dat")

            ' Create random data to write to the file.
            byteArray = New Byte(1000000){}
            randomGenerator.NextBytes(byteArray)

            manualEvents(i) = New ManualResetEvent(false)

            stateInfo = _ 
                New State(fileName, byteArray, manualEvents(i))

            ThreadPool.QueueUserWorkItem(AddressOf _
                Writer.WriteToFile, stateInfo)
        Next i
    
        ' Since ThreadPool threads are background threads, 
        ' wait for the work items to signal before exiting.
        WaitHandle.WaitAll(manualEvents)
        Console.WriteLine("Files written - main exiting.")
    End Sub

End Class
 
' Maintain state to pass to WriteToFile.
Public Class State

    Public fileName As String
    Public byteArray As Byte()
    Public manualEvent As ManualResetEvent

    Sub New(fileName As String, byteArray() As Byte, _
        manualEvent As ManualResetEvent)
    
        Me.fileName = fileName
        Me.byteArray = byteArray
        Me.manualEvent = manualEvent
    End Sub

End Class

Public Class Writer

    Private Sub New()
    End Sub

    Shared workItemCount As Integer = 0

    Shared Sub WriteToFile(state As Object)
        Dim workItemNumber As Integer = workItemCount
        Interlocked.Increment(workItemCount)
        Console.WriteLine("Starting work item {0}.", _
            workItemNumber.ToString())
        Dim stateInfo As State = CType(state, State)
        Dim fileWriter As FileStream = Nothing

        ' Create and write to the file.
        Try
            fileWriter = New FileStream( _
                stateInfo.fileName, FileMode.Create)
            fileWriter.Write(stateInfo.byteArray, _
                0, stateInfo.byteArray.Length)
        Finally
            If Not fileWriter Is Nothing Then
                fileWriter.Close()
            End If

            ' Signal Main that the work item has finished.
            Console.WriteLine("Ending work item {0}.", _
                workItemNumber.ToString())
            stateInfo.manualEvent.Set()
        End Try
    End Sub

End Class

Remarks

AbandonedMutexException is new in the .NET Framework version 2.0. In previous versions, the WaitAll method returns true when a mutex is abandoned. An abandoned mutex often indicates a serious coding error. In the case of a system-wide mutex, it might indicate that an application has been terminated abruptly (for example, by using Windows Task Manager). The exception contains information useful for debugging.

The WaitAll method returns when all the handles are signaled. On some implementations, if more than 64 handles are passed, a NotSupportedException is thrown. If the array contains duplicates, the call fails with a DuplicateWaitObjectException.

Note

The WaitAll method is not supported on threads that have STAThreadAttribute.

Calling this method overload is equivalent to calling the WaitAll(WaitHandle[], Int32, Boolean) method overload and specifying -1 (or Timeout.Infinite) for millisecondsTimeout and true for exitContext.

Applies to