Sleep Method (Int32)
.NET Framework Class Library
Thread..::.Sleep Method (Int32)

Updated: August 2009

Suspends the current thread for a specified time.

Namespace:  System.Threading
Assembly:  mscorlib (in mscorlib.dll)
Visual Basic (Declaration)
Public Shared Sub Sleep ( _
    millisecondsTimeout As Integer _
)
Visual Basic (Usage)
Dim millisecondsTimeout As Integer

Thread.Sleep(millisecondsTimeout)
C#
public static void Sleep(
    int millisecondsTimeout
)
Visual C++
public:
static void Sleep(
    int millisecondsTimeout
)
JScript
public static function Sleep(
    millisecondsTimeout : int
)

Parameters

millisecondsTimeout
Type: System..::.Int32
The number of milliseconds for which the thread is blocked. Specify zero (0) to indicate that this thread should be suspended to allow other waiting threads to execute. Specify Infinite to block the thread indefinitely.
ExceptionCondition
ArgumentOutOfRangeException

The time-out value is negative and is not equal to Infinite.

The thread will not be scheduled for execution by the operating system for the amount of time specified. This method changes the state of the thread to include WaitSleepJoin.

This method does not perform standard COM and SendMessage pumping.

NoteNote:

If you need to sleep on a thread that has STAThreadAttribute, but you want to perform standard COM and SendMessage pumping, consider using one of the overloads of the Join method that specifies a timeout interval.

The following example uses the Sleep method to block the application's main thread.

Visual Basic
Imports System.Threading

Class Example

    Shared Sub Main()

        For i As Integer = 0 To 4
            Console.WriteLine("Sleep for 2 seconds.")
            Thread.Sleep(2000)
        Next

        Console.WriteLine("Main thread exits.")
    End Sub
End Class

' This example produces the following output:
'
'Sleep for 2 seconds.
'Sleep for 2 seconds.
'Sleep for 2 seconds.
'Sleep for 2 seconds.
'Sleep for 2 seconds.
'Main thread exits.
C#
using System;
using System.Threading;

class Example
{
    static void Main()
    {
        for (int i = 0; i < 5; i++)
        {
            Console.WriteLine("Sleep for 2 seconds.");
            Thread.Sleep(2000);
        }

        Console.WriteLine("Main thread exits.");
    }
}

/* This example produces the following output:

Sleep for 2 seconds.
Sleep for 2 seconds.
Sleep for 2 seconds.
Sleep for 2 seconds.
Sleep for 2 seconds.
Main thread exits.
 */
Visual C++
using namespace System;
using namespace System::Threading;

int main()
{
    for (int i = 0; i < 5; i++)
    {
        Console::WriteLine("Sleep for 2 seconds.");
        Thread::Sleep(2000);
    }

    Console::WriteLine("Main thread exits.");
}

/* This example produces the following output:

Sleep for 2 seconds.
Sleep for 2 seconds.
Sleep for 2 seconds.
Sleep for 2 seconds.
Sleep for 2 seconds.
Main thread exits.
 */

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

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

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

Date

History

Reason

August 2009

Simplified example.

Customer feedback.

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How to get the line of the code running in Visual Studio 2008?      arabcoder   |   Edit   |   Show History
like the ansi C __LINE__ ?, thank you

Ghazi, from Libanon
Forcing of a Context Switch      LukeSkywalker   |   Edit   |   Show History
On page 168 (first edition) of Joe Duffy's Concurrent Programming on Windows (link below), Joe states that "if there are runnable threads at a lower priority [and the duration argument is 0], the calling thread will continue running instead of yielding to the other threads" which introduces a potential problem.

It is common to call Sleep(0) to 'force' a context switch, sometimes to avoid deadlocks, however the switch may not take place if the thread has a higher priority than its peers.


Further, Joe writes "passing a value greater than 0 for the argument unconditionally results in a context switch".

http://www.amazon.co.uk/gp/product/032143482X?ie=UTF8&tag=lukepupl-21&linkCode=as2&camp=1634&creative=19450&creativeASIN=032143482X


Also note that the time's accuracy is affected by the granularity of the system clock - commonly 10ms. See Interrupt Rate Granularity at the following address for an emprical example:

http://software.intel.com/en-us/articles/cpu-power-utilization-on-intel-architectures/
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