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SpinWait.Reset Method

Resets the spin counter.

Namespace:  System.Threading
Assembly:  mscorlib (in mscorlib.dll)

public void Reset()

This makes SpinOnce and NextSpinWillYield behave as though no calls to SpinOnce had been issued on this instance. If a SpinWait instance is reused many times, it may be useful to reset it to avoid yielding too soon.

The following is an example of using SpinWait in a simple lock-free stack implementation. (This is just an example. If an efficient, thread-safe stack is needed, consider using ConcurrentStack.)

// C#

public class LockFreeStack<T>

{

private volatile Node m_head;

private class Node { public Node Next; public T Value; }

public void Push(T item)

{

var spin = new SpinWait();

Node node = new Node { Value = item }, head;

while (true)

{

head = m_head;

node.Next = head;

if (Interlocked.CompareExchange(ref m_head, node, head) == head) break;

spin.SpinOnce();

}

}

public bool TryPop(out T result)

{

result = default(T);

var spin = new SpinWait();

Node head;

while (true)

{

head = m_head;

if (head == null) return false;

if (Interlocked.CompareExchange(ref m_head, head.Next, head) == head)

{

result = head.Value;

return true;

}

spin.SpinOnce();

}

}

}

' Visual Basic

Public Class LockFreeStack(Of T)

Private m_head As Node

Private Class Node

Public [Next] As Node

Public Value As T

End Class

Public Sub Push(ByVal item As T)

Dim spin As New SpinWait()

Dim head As Node, node As New Node With {.Value = item}

While True

Thread.MemoryBarrier()

head = m_head

node.Next = head

If Interlocked.CompareExchange(m_head, node, head) Is head Then Exit While

spin.SpinOnce()

End While

End Sub

Public Function TryPop(ByRef result As T) As Boolean

result = CType(Nothing, T)

Dim spin As New SpinWait()

Dim head As Node

While True

Thread.MemoryBarrier()

head = m_head

If head Is Nothing Then Return False

If Interlocked.CompareExchange(m_head, head.Next, head) Is head Then

result = head.Value

Return True

End If

spin.SpinOnce()

End While

End Function

End Class

.NET Framework

Supported in: 4

.NET Framework Client Profile

Supported in: 4

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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