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WDF_REQUEST_SEND_OPTIONS_FLAGS enumeration

[Applies to KMDF and UMDF]

The WDF_REQUEST_SEND_OPTIONS_FLAGS enumeration type defines flags that are used in a driver's WDF_REQUEST_SEND_OPTIONS structure.

Syntax


typedef enum _WDF_REQUEST_SEND_OPTIONS_FLAGS { 
  WDF_REQUEST_SEND_OPTION_TIMEOUT                       = 0x0000001,
  WDF_REQUEST_SEND_OPTION_SYNCHRONOUS                   = 0x0000002,
  WDF_REQUEST_SEND_OPTION_IGNORE_TARGET_STATE           = 0x0000004,
  WDF_REQUEST_SEND_OPTION_SEND_AND_FORGET               = 0x0000008,
  WDF_REQUEST_SEND_OPTION_IMPERSONATE_CLIENT            = 0x00010000,
  WDF_REQUEST_SEND_OPTION_IMPERSONATION_IGNORE_FAILURE  = 0x00020000
} WDF_REQUEST_SEND_OPTIONS_FLAGS;

Constants

WDF_REQUEST_SEND_OPTION_TIMEOUT

If the driver sets this flag, the Timeout member of the WDF_REQUEST_SEND_OPTIONS structure is valid.

WDF_REQUEST_SEND_OPTION_SYNCHRONOUS

If the driver sets this flag, the framework handles the associated I/O request synchronously. (The driver does not have to set this flag if it is calling an object method whose name ends with "Synchronously", such as WdfIoTargetSendReadSynchronously.)

WDF_REQUEST_SEND_OPTION_IGNORE_TARGET_STATE

If the driver sets this flag, the framework sends the I/O request to the I/O target, regardless of the I/O target's state. If not set, the framework queues the request if the target is stopped. Setting this flag allows a driver to send a request, such as a request to reset a USB pipe, to a device after the driver has called WdfIoTargetStop.

WDF_REQUEST_SEND_OPTION_SEND_AND_FORGET

If the driver sets this flag, the driver is sending the request asynchronously and does not need to be notified when the request is completed or canceled. The framework sends the I/O request to the I/O target, regardless of the I/O target's state. The driver does not set a CompletionRoutine callback function or call WdfRequestComplete for the request. If the driver sets this flag, it cannot set any other flags. For more information about this flag, see the following Remarks section.

WDF_REQUEST_SEND_OPTION_IMPERSONATE_CLIENT

This flag applies to UMDF only. If set, and if the I/O request type is WdfRequestTypeCreate, the WdfRequestSend method attempts to pass the client's impersonation level to the driver's I/O target. The WdfRequestSend method returns an error code if the impersonation attempt fails, unless the driver also sets the WDF_REQUEST_SEND_OPTION_IMPERSONATION_IGNORE_FAILURE flag.

WDF_REQUEST_SEND_OPTION_IMPERSONATION_IGNORE_FAILURE

This flag applies to UMDF only. If set, the framework still sends the request even if impersonation fails. You can use this value only with WDF_REQUEST_SEND_OPTION_IMPERSONATE_CLIENT.

Remarks

A driver that sets the WDF_REQUEST_SEND_OPTION_SEND_AND_FORGET flag typically does not format the I/O request before it calls WdfRequestSend to send the request to an I/O target. In fact, a driver that sets this flag must not call any of the WdfIoTargetFormatRequestForXxx methods before it calls WdfRequestSend. The driver can use only the WdfRequestFormatRequestUsingCurrentType or WdfRequestWdmFormatUsingStackLocation method to format the request.

Your driver cannot set the WDF_REQUEST_SEND_OPTION_SEND_AND_FORGET flag in the following situations:

For the UMDF version of this enumeration, see WDF_REQUEST_SEND_OPTIONS_FLAGS (UMDF).

Requirements

Minimum KMDF version

1.0

Minimum UMDF version

2.0

Header

Wdfrequest.h (include Wdf.h)

See also

WdfIoTargetStop
WDF_REQUEST_SEND_OPTIONS

 

 

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