Thread.Sleep Method

Definition

Namespace:

System.Threading

Assembly:

System.Threading.Thread.dll

Suspends the current thread for the specified amount of time.

Overloads

Sleep(Int32)	Suspends the current thread for the specified number of milliseconds.
Sleep(TimeSpan)	Suspends the current thread for the specified amount of time.

Sleep(Int32)

Source:

Thread.cs

Suspends the current thread for the specified number of milliseconds.

public:
 static void Sleep(int millisecondsTimeout);

public static void Sleep (int millisecondsTimeout);

static member Sleep : int -> unit

Public Shared Sub Sleep (millisecondsTimeout As Integer)

Parameters

millisecondsTimeout

Int32

The number of milliseconds for which the thread is suspended. If the value of the millisecondsTimeout argument is zero, the thread relinquishes the remainder of its time slice to any thread of equal priority that is ready to run. If there are no other threads of equal priority that are ready to run, execution of the current thread is not suspended.

Exceptions

ArgumentOutOfRangeException

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

Examples

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

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.
 */

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.
 */

open System.Threading

for _ = 0 to 4 do
    printfn "Sleep for 2 seconds."
    Thread.Sleep 2000

printfn "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.

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.

Remarks

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.

You can specify Timeout.Infinite for the millisecondsTimeout parameter to suspend the thread indefinitely. However, we recommend that you use other System.Threading classes such as Mutex, Monitor, EventWaitHandle, or Semaphore instead to synchronize threads or manage resources.

The system clock ticks at a specific rate called the clock resolution. The actual timeout might not be exactly the specified timeout, because the specified timeout will be adjusted to coincide with clock ticks. For more information on clock resolution and the waiting time, see the Sleep function from the Windows system APIs.

This method does not perform standard COM and SendMessage pumping.

Note

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.

Sleep(TimeSpan)

Source:

Thread.cs

Suspends the current thread for the specified amount of time.

public:
 static void Sleep(TimeSpan timeout);

public static void Sleep (TimeSpan timeout);

static member Sleep : TimeSpan -> unit

Public Shared Sub Sleep (timeout As TimeSpan)

Parameters

timeout

TimeSpan

The amount of time for which the thread is suspended. If the value of the timeout argument is Zero, the thread relinquishes the remainder of its time slice to any thread of equal priority that is ready to run. If there are no other threads of equal priority that are ready to run, execution of the current thread is not suspended.

Exceptions

ArgumentOutOfRangeException

The value of timeout is negative and is not equal to Infinite in milliseconds, or is greater than Int32.MaxValue milliseconds.

Examples

The following example uses the Sleep(TimeSpan) method overload to block the application's main thread five times, for two seconds each time.

using namespace System;
using namespace System::Threading;

int main()
{
    TimeSpan interval = TimeSpan(0, 0, 2);

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

    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.
 */

using System;
using System.Threading;

class Example
{
    static void Main()
    {
        TimeSpan interval = new TimeSpan(0, 0, 2);

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

        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.
 */

open System
open System.Threading

let interval = TimeSpan(0, 0, 2)

for _ = 0 to 4 do
    printfn "Sleep for 2 seconds."
    Thread.Sleep interval

printfn "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.

Imports System.Threading

Class Example

    Shared Sub Main()

        Dim interval As New TimeSpan(0, 0, 2)

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

Remarks

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.

You can specify Timeout.InfiniteTimeSpan for the timeout parameter to suspend the thread indefinitely. However, we recommend that you use other System.Threading classes such as Mutex, Monitor, EventWaitHandle, or Semaphore instead to synchronize threads or manage resources.

This overload of Sleep uses the total number of whole milliseconds in timeout. Fractional milliseconds are discarded.

This method does not perform standard COM and SendMessage pumping.

Note

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.