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IoStartNextPacketByKey routine

The IoStartNextPacketByKey routine dequeues the next I/O request packet from the specified device object's associated device queue according to a specified sort-key value and calls the driver's StartIo routine with that IRP.

Syntax


VOID IoStartNextPacketByKey(
  _In_  PDEVICE_OBJECT DeviceObject,
  _In_  BOOLEAN Cancelable,
  _In_  ULONG Key
);

Parameters

DeviceObject [in]

Pointer to the device object for which the IRP is to be dequeued.

Cancelable [in]

Specifies whether IRPs in the device queue can be canceled.

Key [in]

Specifies the sort key that determines which entry to remove from the queue.

Return value

None

Remarks

If there are no IRPs currently in the device queue for the target device object, this routine simply returns control to the caller.

If the driver passed a pointer to a cancel routine when it called IoStartPacket, it should pass TRUE in the Cancelable parameter. If Cancelable is TRUE, the I/O manager will use the cancel spin lock to protect the device queue and the current IRP.

Drivers that do not have a StartIo routine cannot call IoStartNextPacketByKey.

Callers of IoStartNextPacketByKey must be running at IRQL <= DISPATCH_LEVEL. Usually, this routine is called from a device driver's DpcForIsr or CustomDpc routine, both of which are run at IRQL = DISPATCH_LEVEL.

Requirements

Version

Available starting with Windows 2000.

Header

Wdm.h (include Wdm.h, Ntddk.h, or Ntifs.h)

Library

Ntoskrnl.lib

IRQL

<= DISPATCH_LEVEL

See also

DEVICE_OBJECT
IoStartNextPacket
IoStartPacket

 

 

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