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IoCompleteRequest routine

The IoCompleteRequest routine indicates that the caller has completed all processing for a given I/O request and is returning the given IRP to the I/O manager.


VOID IoCompleteRequest(
  _In_ PIRP  Irp,
  _In_ CCHAR PriorityBoost


Irp [in]

Pointer to the IRP to be completed.

PriorityBoost [in]

Specifies a system-defined constant by which to increment the run-time priority of the original thread that requested the operation. This value is IO_NO_INCREMENT if the original thread requested an operation the driver could complete quickly (so the requesting thread is not compensated for its assumed wait for I/O to be completed) or if the IRP is completed with an error. Otherwise, the set of PriorityBoost constants are device-type-specific. See Ntddk.h or Wdm.h for these constants.

Return value



When a driver has finished all processing for a given IRP, it calls IoCompleteRequest. The I/O manager checks the IRP to determine whether any higher-level drivers have set up an IoCompletion routine for the IRP. If so, each IoCompletion routine is called, in turn, until every layered driver in the chain has completed the IRP.

When all drivers have completed a given IRP, the I/O manager returns status to the original requester of the operation. Note that a higher-level driver that sets up a driver-created IRP must supply an IoCompletion routine to release the IRP it created.

Never call IoCompleteRequest while holding a spin lock. Attempting to complete an IRP while holding a spin lock can cause deadlocks.


Target platform



Available starting with Windows 2000.


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







DDI compliance rules

CompleteRequest, CompleteRequestStatusCheck, DoubleCompletion, IoAllocateComplete, IoBuildFsdComplete, IoSetCompletionExCompleteIrp, IrpProcessingComplete, MarkIrpPending, PendedCompletedRequest, PendedCompletedRequest2, PendedCompletedRequest3, PendedCompletedRequestEx, PnpIrpCompletion, SpinLockSafe, WmiComplete, HwStorPortProhibitedDDIs, SpinLockSafe(storport)

See also




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