Registers a delegate to wait for a WaitHandle, specifying a TimeSpan value for the time-out.
Assembly: mscorlib (in mscorlib.dll)
Public Shared Function RegisterWaitForSingleObject ( _
waitObject As WaitHandle, _
callBack As WaitOrTimerCallback, _
state As Object, _
timeout As TimeSpan, _
executeOnlyOnce As Boolean _
) As RegisteredWaitHandlepublic static RegisteredWaitHandle RegisterWaitForSingleObject(
WaitHandle waitObject,
WaitOrTimerCallback callBack,
Object state,
TimeSpan timeout,
bool executeOnlyOnce
)public:
static RegisteredWaitHandle^ RegisterWaitForSingleObject(
WaitHandle^ waitObject,
WaitOrTimerCallback^ callBack,
Object^ state,
TimeSpan timeout,
bool executeOnlyOnce
)static member RegisterWaitForSingleObject :
waitObject:WaitHandle *
callBack:WaitOrTimerCallback *
state:Object *
timeout:TimeSpan *
executeOnlyOnce:bool -> RegisteredWaitHandle
Parameters
- waitObject
- Type: System.Threading
. . :: . WaitHandle
The WaitHandle to register. Use a WaitHandle other than Mutex.
- callBack
- Type: System.Threading
. . :: . WaitOrTimerCallback
The WaitOrTimerCallback delegate to call when the waitObject parameter is signaled.
- state
- Type: System
. . :: . Object
The object passed to the delegate.
- timeout
- Type: System
. . :: . TimeSpan
The time-out represented by a TimeSpan. If timeout is 0 (zero), the function tests the object's state and returns immediately. If timeout is -1, the function's time-out interval never elapses.
- executeOnlyOnce
- Type: System
. . :: . Boolean
true to indicate that the thread will no longer wait on the waitObject parameter after the delegate has been called; false to indicate that the timer is reset every time the wait operation completes until the wait is unregistered.
Return Value
Type: System.ThreadingThe RegisteredWaitHandle that encapsulates the native handle.
| Exception | Condition |
|---|---|
| ArgumentOutOfRangeException | The timeout parameter is less than -1. |
| NotSupportedException | The timeout parameter is greater than Int32 |
When you are finished using the RegisteredWaitHandle that is returned by this method, call its RegisteredWaitHandle
The RegisterWaitForSingleObject method queues the specified delegate to the thread pool. A worker thread will execute the delegate when one of the following occurs:
The specified object is in the signaled state.
The time-out interval elapses.
The RegisterWaitForSingleObject method checks the current state of the specified object's WaitHandle. If the object's state is unsignaled, the method registers a wait operation. The wait operation is performed by a thread from the thread pool. The delegate is executed by a worker thread when the object's state becomes signaled or the time-out interval elapses. If the timeOutInterval parameter is not 0 (zero) and the executeOnlyOnce parameter is false, the timer is reset every time the event is signaled or the time-out interval elapses.
.gif) Important |
|---|
Using a Mutex for waitObject does not provide mutual exclusion for the callbacks because the underlying Win32 API uses the default WT_EXECUTEDEFAULT flag, so each callback is dispatched on a separate thread pool thread. Instead of a Mutex, use a Semaphore with a maximum count of 1. |
To cancel the wait operation, call the RegisteredWaitHandle
The wait thread uses the Win32 WaitForMultipleObjects function to monitor registered wait operations. Therefore, if you must use the same native operating system handle in multiple calls to RegisterWaitForSingleObject, you must duplicate the handle using the Win32 DuplicateHandle function. Note that you should not pulse an event object passed to RegisterWaitForSingleObject, because the wait thread might not detect that the event is signaled before it is reset.
Before returning, the function modifies the state of some types of synchronization objects. Modification occurs only for the object whose signaled state caused the wait condition to be satisfied. For example, the count of a semaphore is decreased by one.
Version Information
Starting with the .NET Framework version 2.0, the Thread
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, 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.