ThreadPool.UnsafeRegisterWaitForSingleObject Method

Definition

Namespace:

System.Threading

Assembly:

System.Threading.ThreadPool.dll

Registers a delegate to wait for a WaitHandle, but does not propagate the calling stack to the worker thread.

Overloads

UnsafeRegisterWaitForSingleObject(WaitHandle, WaitOrTimerCallback, Object, TimeSpan, Boolean)	Registers a delegate to wait for a WaitHandle, specifying a TimeSpan value for the time-out. This method does not propagate the calling stack to the worker thread.
UnsafeRegisterWaitForSingleObject(WaitHandle, WaitOrTimerCallback, Object, Int32, Boolean)	Registers a delegate to wait for a WaitHandle, using a 32-bit signed integer for the time-out in milliseconds. This method does not propagate the calling stack to the worker thread.
UnsafeRegisterWaitForSingleObject(WaitHandle, WaitOrTimerCallback, Object, Int64, Boolean)	Registers a delegate to wait for a WaitHandle, specifying a 64-bit signed integer for the time-out in milliseconds. This method does not propagate the calling stack to the worker thread.
UnsafeRegisterWaitForSingleObject(WaitHandle, WaitOrTimerCallback, Object, UInt32, Boolean)	Registers a delegate to wait for a WaitHandle, specifying a 32-bit unsigned integer for the time-out in milliseconds. This method does not propagate the calling stack to the worker thread.

UnsafeRegisterWaitForSingleObject(WaitHandle, WaitOrTimerCallback, Object, TimeSpan, Boolean)

Source:

ThreadPoolWorkQueue.cs

Registers a delegate to wait for a WaitHandle, specifying a TimeSpan value for the time-out. This method does not propagate the calling stack to the worker thread.

public:
 static System::Threading::RegisteredWaitHandle ^ UnsafeRegisterWaitForSingleObject(System::Threading::WaitHandle ^ waitObject, System::Threading::WaitOrTimerCallback ^ callBack, System::Object ^ state, TimeSpan timeout, bool executeOnlyOnce);

[System.Runtime.Versioning.UnsupportedOSPlatform("browser")]
public static System.Threading.RegisteredWaitHandle UnsafeRegisterWaitForSingleObject (System.Threading.WaitHandle waitObject, System.Threading.WaitOrTimerCallback callBack, object? state, TimeSpan timeout, bool executeOnlyOnce);

[<System.Runtime.Versioning.UnsupportedOSPlatform("browser")>]
static member UnsafeRegisterWaitForSingleObject : System.Threading.WaitHandle * System.Threading.WaitOrTimerCallback * obj * TimeSpan * bool -> System.Threading.RegisteredWaitHandle

Public Shared Function UnsafeRegisterWaitForSingleObject (waitObject As WaitHandle, callBack As WaitOrTimerCallback, state As Object, timeout As TimeSpan, executeOnlyOnce As Boolean) As RegisteredWaitHandle

Parameters

waitObject

WaitHandle

The WaitHandle to register. Use a WaitHandle other than Mutex.

callBack

WaitOrTimerCallback

The delegate to call when the waitObject parameter is signaled.

state

Object

The object that is passed to the delegate.

timeout

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

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.

Returns

RegisteredWaitHandle

The RegisteredWaitHandle object that can be used to cancel the registered wait operation.

Attributes

UnsupportedOSPlatformAttribute

Exceptions

ArgumentOutOfRangeException

The timeout parameter is less than -1.

NotSupportedException

The timeout parameter is greater than Int32.MaxValue.

SecurityException

The caller does not have the required permission.

Remarks

Unlike the RegisterWaitForSingleObject method, UnsafeRegisterWaitForSingleObject does not propagate the calling stack to the worker thread. This allows code to lose the calling stack and thereby to elevate its security privileges.

Caution

Using UnsafeRegisterWaitForSingleObject could inadvertently open up a security hole. Code access security bases its permission checks on the permissions of all the callers on the stack. When work is queued on a thread pool thread using UnsafeRegisterWaitForSingleObject, the stack of the thread pool thread will not have the context of the actual callers. Malicious code might be able exploit this to avoid permission checks.

Using a Mutex for waitObject does not provide mutual exclusion for the callbacks because the underlying Windows API uses the default WT_EXECUTEDEFAULT flag, so each callback is dispatched on a separate thread pool thread.

When you are finished using the RegisteredWaitHandle that is returned by this method, call its RegisteredWaitHandle.Unregister method to release references to the wait handle. We recommend that you always call the RegisteredWaitHandle.Unregister method, even if you specify true for executeOnlyOnce. Garbage collection works more efficiently if you call the RegisteredWaitHandle.Unregister method instead of depending on the registered wait handle's finalizer.

See also

• The Managed Thread Pool

UnsafeRegisterWaitForSingleObject(WaitHandle, WaitOrTimerCallback, Object, Int32, Boolean)

Source:

ThreadPoolWorkQueue.cs

Registers a delegate to wait for a WaitHandle, using a 32-bit signed integer for the time-out in milliseconds. This method does not propagate the calling stack to the worker thread.

public:
 static System::Threading::RegisteredWaitHandle ^ UnsafeRegisterWaitForSingleObject(System::Threading::WaitHandle ^ waitObject, System::Threading::WaitOrTimerCallback ^ callBack, System::Object ^ state, int millisecondsTimeOutInterval, bool executeOnlyOnce);

[System.Runtime.Versioning.UnsupportedOSPlatform("browser")]
public static System.Threading.RegisteredWaitHandle UnsafeRegisterWaitForSingleObject (System.Threading.WaitHandle waitObject, System.Threading.WaitOrTimerCallback callBack, object? state, int millisecondsTimeOutInterval, bool executeOnlyOnce);

[<System.Runtime.Versioning.UnsupportedOSPlatform("browser")>]
static member UnsafeRegisterWaitForSingleObject : System.Threading.WaitHandle * System.Threading.WaitOrTimerCallback * obj * int * bool -> System.Threading.RegisteredWaitHandle

Public Shared Function UnsafeRegisterWaitForSingleObject (waitObject As WaitHandle, callBack As WaitOrTimerCallback, state As Object, millisecondsTimeOutInterval As Integer, executeOnlyOnce As Boolean) As RegisteredWaitHandle

Parameters

waitObject

WaitHandle

The WaitHandle to register. Use a WaitHandle other than Mutex.

callBack

WaitOrTimerCallback

The delegate to call when the waitObject parameter is signaled.

state

Object

The object that is passed to the delegate.

millisecondsTimeOutInterval

Int32

The time-out in milliseconds. If the millisecondsTimeOutInterval parameter is 0 (zero), the function tests the object's state and returns immediately. If millisecondsTimeOutInterval is -1, the function's time-out interval never elapses.

executeOnlyOnce

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.

Returns

RegisteredWaitHandle

The RegisteredWaitHandle object that can be used to cancel the registered wait operation.

Attributes

UnsupportedOSPlatformAttribute

Exceptions

ArgumentOutOfRangeException

The millisecondsTimeOutInterval parameter is less than -1.

SecurityException

The caller does not have the required permission.

Remarks

Unlike the RegisterWaitForSingleObject method, UnsafeRegisterWaitForSingleObject does not propagate the calling stack to the worker thread. This allows code to lose the calling stack and thereby to elevate its security privileges.

Caution

Using UnsafeRegisterWaitForSingleObject could inadvertently open up a security hole. Code access security bases its permission checks on the permissions of all the callers on the stack. When work is queued on a thread pool thread using UnsafeRegisterWaitForSingleObject, the stack of the thread pool thread will not have the context of the actual callers. Malicious code might be able exploit this to avoid permission checks.

Using a Mutex for waitObject does not provide mutual exclusion for the callbacks because the underlying Windows API uses the default WT_EXECUTEDEFAULT flag, so each callback is dispatched on a separate thread pool thread.

When you are finished using the RegisteredWaitHandle that is returned by this method, call its RegisteredWaitHandle.Unregister method to release references to the wait handle. We recommend that you always call the RegisteredWaitHandle.Unregister method, even if you specify true for executeOnlyOnce. Garbage collection works more efficiently if you call the RegisteredWaitHandle.Unregister method instead of depending on the registered wait handle's finalizer.

See also

• The Managed Thread Pool

UnsafeRegisterWaitForSingleObject(WaitHandle, WaitOrTimerCallback, Object, Int64, Boolean)

Source:

ThreadPoolWorkQueue.cs

Registers a delegate to wait for a WaitHandle, specifying a 64-bit signed integer for the time-out in milliseconds. This method does not propagate the calling stack to the worker thread.

public:
 static System::Threading::RegisteredWaitHandle ^ UnsafeRegisterWaitForSingleObject(System::Threading::WaitHandle ^ waitObject, System::Threading::WaitOrTimerCallback ^ callBack, System::Object ^ state, long millisecondsTimeOutInterval, bool executeOnlyOnce);

[System.Runtime.Versioning.UnsupportedOSPlatform("browser")]
public static System.Threading.RegisteredWaitHandle UnsafeRegisterWaitForSingleObject (System.Threading.WaitHandle waitObject, System.Threading.WaitOrTimerCallback callBack, object? state, long millisecondsTimeOutInterval, bool executeOnlyOnce);

[<System.Runtime.Versioning.UnsupportedOSPlatform("browser")>]
static member UnsafeRegisterWaitForSingleObject : System.Threading.WaitHandle * System.Threading.WaitOrTimerCallback * obj * int64 * bool -> System.Threading.RegisteredWaitHandle

Public Shared Function UnsafeRegisterWaitForSingleObject (waitObject As WaitHandle, callBack As WaitOrTimerCallback, state As Object, millisecondsTimeOutInterval As Long, executeOnlyOnce As Boolean) As RegisteredWaitHandle

Parameters

waitObject

WaitHandle

The WaitHandle to register. Use a WaitHandle other than Mutex.

callBack

WaitOrTimerCallback

The delegate to call when the waitObject parameter is signaled.

state

Object

The object that is passed to the delegate.

millisecondsTimeOutInterval

Int64

The time-out in milliseconds. If the millisecondsTimeOutInterval parameter is 0 (zero), the function tests the object's state and returns immediately. If millisecondsTimeOutInterval is -1, the function's time-out interval never elapses.

executeOnlyOnce

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.

Returns

RegisteredWaitHandle

The RegisteredWaitHandle object that can be used to cancel the registered wait operation.

Attributes

UnsupportedOSPlatformAttribute

Exceptions

ArgumentOutOfRangeException

The millisecondsTimeOutInterval parameter is less than -1.

SecurityException

The caller does not have the required permission.

Remarks

Unlike the RegisterWaitForSingleObject method, UnsafeRegisterWaitForSingleObject does not propagate the calling stack to the worker thread. This allows code to lose the calling stack and thereby to elevate its security privileges.

Caution

Using UnsafeRegisterWaitForSingleObject could inadvertently open up a security hole. Code access security bases its permission checks on the permissions of all the callers on the stack. When work is queued on a thread pool thread using UnsafeRegisterWaitForSingleObject, the stack of the thread pool thread will not have the context of the actual callers. Malicious code might be able exploit this to avoid permission checks.

Using a Mutex for waitObject does not provide mutual exclusion for the callbacks because the underlying Windows API uses the default WT_EXECUTEDEFAULT flag, so each callback is dispatched on a separate thread pool thread.

When you are finished using the RegisteredWaitHandle that is returned by this method, call its RegisteredWaitHandle.Unregister method to release references to the wait handle. We recommend that you always call the RegisteredWaitHandle.Unregister method, even if you specify true for executeOnlyOnce. Garbage collection works more efficiently if you call the RegisteredWaitHandle.Unregister method instead of depending on the registered wait handle's finalizer.

See also

• The Managed Thread Pool

UnsafeRegisterWaitForSingleObject(WaitHandle, WaitOrTimerCallback, Object, UInt32, Boolean)

Source:

ThreadPoolWorkQueue.cs

Important

This API is not CLS-compliant.

Registers a delegate to wait for a WaitHandle, specifying a 32-bit unsigned integer for the time-out in milliseconds. This method does not propagate the calling stack to the worker thread.

public:
 static System::Threading::RegisteredWaitHandle ^ UnsafeRegisterWaitForSingleObject(System::Threading::WaitHandle ^ waitObject, System::Threading::WaitOrTimerCallback ^ callBack, System::Object ^ state, System::UInt32 millisecondsTimeOutInterval, bool executeOnlyOnce);

[System.CLSCompliant(false)]
[System.Runtime.Versioning.UnsupportedOSPlatform("browser")]
public static System.Threading.RegisteredWaitHandle UnsafeRegisterWaitForSingleObject (System.Threading.WaitHandle waitObject, System.Threading.WaitOrTimerCallback callBack, object? state, uint millisecondsTimeOutInterval, bool executeOnlyOnce);

[<System.CLSCompliant(false)>]
[<System.Runtime.Versioning.UnsupportedOSPlatform("browser")>]
static member UnsafeRegisterWaitForSingleObject : System.Threading.WaitHandle * System.Threading.WaitOrTimerCallback * obj * uint32 * bool -> System.Threading.RegisteredWaitHandle

Public Shared Function UnsafeRegisterWaitForSingleObject (waitObject As WaitHandle, callBack As WaitOrTimerCallback, state As Object, millisecondsTimeOutInterval As UInteger, executeOnlyOnce As Boolean) As RegisteredWaitHandle

Parameters

waitObject

WaitHandle

The WaitHandle to register. Use a WaitHandle other than Mutex.

callBack

WaitOrTimerCallback

The delegate to call when the waitObject parameter is signaled.

state

Object

The object that is passed to the delegate.

millisecondsTimeOutInterval

UInt32

The time-out in milliseconds. If the millisecondsTimeOutInterval parameter is 0 (zero), the function tests the object's state and returns immediately. If millisecondsTimeOutInterval is -1, the function's time-out interval never elapses.

executeOnlyOnce

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.

Returns

RegisteredWaitHandle

The RegisteredWaitHandle object that can be used to cancel the registered wait operation.

Attributes

CLSCompliantAttribute UnsupportedOSPlatformAttribute

Exceptions

SecurityException

The caller does not have the required permission.

Remarks

Unlike the RegisterWaitForSingleObject method, UnsafeRegisterWaitForSingleObject does not propagate the calling stack to the worker thread. This allows code to lose the calling stack and thereby to elevate its security privileges.

Caution

Using UnsafeRegisterWaitForSingleObject could inadvertently open up a security hole. Code access security bases its permission checks on the permissions of all the callers on the stack. When work is queued on a thread pool thread using UnsafeRegisterWaitForSingleObject, the stack of the thread pool thread will not have the context of the actual callers. Malicious code might be able exploit this to avoid permission checks.

Using a Mutex for waitObject does not provide mutual exclusion for the callbacks because the underlying Windows API uses the default WT_EXECUTEDEFAULT flag, so each callback is dispatched on a separate thread pool thread.

When you are finished using the RegisteredWaitHandle that is returned by this method, call its RegisteredWaitHandle.Unregister method to release references to the wait handle. We recommend that you always call the RegisteredWaitHandle.Unregister method, even if you specify true for executeOnlyOnce. Garbage collection works more efficiently if you call the RegisteredWaitHandle.Unregister method instead of depending on the registered wait handle's finalizer.

See also

• The Managed Thread Pool