WdfObjectGetTypedContext macro

[Applies to KMDF and UMDF]

The WdfObjectGetTypedContext macro returns a pointer to an object's context space.

Syntax


PVOID WdfObjectGetTypedContext(
   Handle,
   Type
);

Parameters

Handle

A handle to a framework object.

Type

The symbol name of a driver-defined structure that describes an object's context space.

Return value

WdfObjectGetTypedContext returns a pointer to the specified object's context space.

Remarks

You can use the WdfObjectGetTypedContext macro to obtain a pointer to any framework object's context space. Use this macro as an alternative to calling an object-specific context accessor method that is created by the WDF_DECLARE_CONTEXT_TYPE macro or the WDF_DECLARE_CONTEXT_TYPE_WITH_NAME macro. Note that if you use WdfObjectGetTypedContext, you still must use WDF_DECLARE_CONTEXT_TYPE or WDF_DECLARE_CONTEXT_TYPE_WITH_NAME to declare your object context.

For more information about these macros, see Framework Object Context Space.

Examples

The following code example defines a context structure (MY_REQUEST_CONTEXT) for a request object and then registers the structure.


typedef struct _MY_REQUEST_CONTEXT {
  LIST_ENTRY ListEntry;
  WDFMEMORY Memory;
} MY_REQUEST_CONTEXT, *PMY_REQUEST_CONTEXT;

WDF_DECLARE_CONTEXT_TYPE(MY_REQUEST_CONTEXT)

The following code example creates a request object and obtains a pointer to its context space.


WDFREQUEST Request;
WDF_OBJECT_ATTRIBUTES MyRequestObjectAttributes;
PMY_REQUEST_CONTEXT pMyContext;

WDF_OBJECT_ATTRIBUTES_INIT(&MyRequestObjectAttributes);
WDF_OBJECT_ATTRIBUTES_SET_CONTEXT_TYPE(
                                       &MyRequestObjectAttributes,
                                       MY_REQUEST_CONTEXT
                                       );
status = WdfRequestCreate(
                          &MyRequestObjectAttributes,
                          NULL,
                          &Request
                          );

if (!NT_SUCCESS(status)) {
    return status;
}
pMyContext = WdfObjectGetTypedContext(
                                      Request,
                                      MY_REQUEST_CONTEXT
                                      );

Requirements

Minimum KMDF version

1.0

Minimum UMDF version

2.0

Header

Wdfobject.h (include Wdf.h)

Library

Wdf01000.sys (see Framework Library Versioning.)

IRQL

Any level

See also

WDF_DECLARE_CONTEXT_TYPE
WDF_DECLARE_CONTEXT_TYPE_WITH_NAME

 

 

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