WDF_OBJECT_ATTRIBUTES_INIT_CONTEXT_TYPE macro

Article
03/01/2023

[Applies to KMDF and UMDF]

The WDF_OBJECT_ATTRIBUTES_INIT_CONTEXT_TYPE macro initializes a driver's WDF_OBJECT_ATTRIBUTES structure and inserts an object's driver-defined context information into the structure.

Syntax

void WDF_OBJECT_ATTRIBUTES_INIT_CONTEXT_TYPE(
    _attributes,
    _contexttype
);

Parameters

_attributes
A pointer to a WDF_OBJECT_ATTRIBUTES structure.

_contexttype
The structure type name of a driver-defined structure that describes the contents of an object's context space.

Return value

This macro does not return a value.

Remarks

Before calling WDF_OBJECT_ATTRIBUTES_INIT_CONTEXT_TYPE, you must call WDF_DECLARE_CONTEXT_TYPE or WDF_DECLARE_CONTEXT_TYPE_WITH_NAME globally (not within a function).

The WDF_OBJECT_ATTRIBUTES_INIT_CONTEXT_TYPE macro combines the WDF_OBJECT_ATTRIBUTES_INIT function and the WDF_OBJECT_ATTRIBUTES_SET_CONTEXT_TYPE macro.

Examples

The following code example defines a WDM_NDIS_REQUEST context structure. Then, the example invokes the WDF_DECLARE_CONTEXT_TYPE_WITH_NAME macro to register the structure and specify that the context accessor method will be named RequestGetMyContext. Then, in a function, the example allocates a WDF_OBJECT_ATTRIBUTES structure, and then initializes the WDF_OBJECT_ATTRIBUTES structure.

typedef struct _WDM_NDIS_REQUEST
{
   PMP_ADAPTER  Adapter;
   NDIS_OID  Oid;
   NDIS_REQUEST_TYPE  RequestType;
   PVOID  InformationBuffer;
   ULONG  InformationBufferLength;
   PULONG  BytesReadOrWritten;
   PULONG  BytesNeeded;
} WDM_NDIS_REQUEST, *PWDM_NDIS_REQUEST;

WDF_DECLARE_CONTEXT_TYPE_WITH_NAME(WDM_NDIS_REQUEST, RequestGetMyContext);

// above are in global space

...

WDF_OBJECT_ATTRIBUTES  attributes;

WDF_OBJECT_ATTRIBUTES_INIT_CONTEXT_TYPE( &attributes, WDM_NDIS_REQUEST );

Requirements

Target platform	Universal
Minimum KMDF version	1.0
Minimum UMDF version	2.0
Header	Wdfobject.h (include Wdf.h)