IID_PPV_ARGS macro (combaseapi.h)

Used to retrieve an interface pointer, supplying the IID value of the requested interface automatically based on the type of the interface pointer used. This avoids a common coding error by checking the type of the value passed at compile time.

Syntax

void IID_PPV_ARGS(
   ppType
);

Parameters

ppType

An address of an interface pointer whose type T is used to determine the type of object being requested. The macro returns the interface pointer through this parameter.

Return value

None

Remarks

A common syntax in methods that retrieve an interface pointer (most notably QueryInterface and CoCreateInstance) includes two parameters:

• An [in] parameter, normally of type REFIID, to specify the IID of the interface to retrieve.
• An [out] parameter, normally of type void**, to receive the interface pointer.

While Windows 7 is the first inclusion of this macro in a public header, it can be used on older systems by defining it manually in your project headers or source code.

The following example shows the use of IID_PPV_ARGS to create the memory property store object using IPropertyStore.

IPropertyStore *pPropertyStore;

CoCreateInstance(CLSID_PropertyStore, NULL, CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&pPropertyStore));

Requirements