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NdisCancelTimerObject function (ndis.h)

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The NdisCancelTimerObject function cancels a timer object that is associated with a previous call to the NdisSetTimerObject function.

Syntax

BOOLEAN NdisCancelTimerObject(
  [in] NDIS_HANDLE TimerObject
);

Parameters

[in] TimerObject

A handle to a timer object that NDIS provides when a driver calls the NdisAllocateTimerObject function.

Return value

NdisCancelTimerObject returns TRUE if the specified timer object is in the system timer queue; otherwise, it returns FALSE.

Remarks

A call to NdisCancelTimerObject cancels execution of a NetTimerCallback function, provided that the last specified timeout interval has not yet expired.

NDIS drivers should call NdisCancelTimerObject first when they are halting or unloading to ensure that a NetTimerCallback function does not attempt to access resources that the driver has already released.

If a nonzero value was specified in the MillisecondsPeriod parameter of the NdisSetTimerObject function, the timer is known as a periodic timer. If a zero value was specified in the MillisecondsPeriod parameter, the timer is known as a one-shot timer. The following points apply to canceling both types of timers:

  • If the caller of NdisCancelTimerObject is canceling a periodic timer, it must be running at IRQL = PASSIVE_LEVEL. Otherwise, the caller of NdisCancelTimerObject should be running at IRQL <= DISPATCH_LEVEL.
  • If the caller of NdisCancelTimerObject is canceling a periodic timer, NdisCancelTimerObject calls KeFlushQueuedDpcs to ensure that the timer is not currently running. Therefore, the caller is not required to have a separate synchronization mechanism to ensure that the timer is not currently being executed on another processor.

    If the caller of NdisCancelTimerObject is canceling a one-shot timer, the caller is required to have a separate synchronization mechanism to ensure the timer is not currently running on another processor. For example, the caller could call NDIS_WAIT_FOR_MUTEX in order to wait for the timer thread to signal a mutex object when the thread is about to complete.

    For more information, see Synchronization and Notification in Network Drivers.

Requirements

Requirement Value
Minimum supported client Supported in NDIS 6.0 and later.
Target Platform Universal
Header ndis.h (include Ndis.h)
Library Ndis.lib
IRQL See Remarks section
DDI compliance rules Irql_Timer_Function(ndis), PeriodicTimer(ndis)

See also

NdisAllocateTimerObject

NdisSetTimerObject

NetTimerCallback