IUnknown::QueryInterface

The QueryInterface method determines if an interface can be used with an object. Used by the following interfaces: IAVIEditStream, IAVIFile, IAVIStream, IAVIStreaming, and IGetFrame.

HRESULT QueryInterface(
  LPUNKNOWN ps,      
  const IID & riid,  
  void *ppvObj       
);
 

Parameters

ps

Address of an IAVIEditStream, IAVIFile, IAVIStream, IAVIStreaming, or IGetFrame interface.

riid

Identifier of the interface being queried.

ppvObj

Address to contain a pointer to the object whose interface is queried or NULL when an interface is not supported.

Return Values

Returns a pointer to the current interface if successful or E_NOINTERFACE otherwise.

Remarks

For handlers written in C++, QueryInterface has the following syntax:

HRESULT QueryInterface(const IID &riid, void *ppvObj); 
 

QuickInfo

  Windows NT: Requires version 3.1 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Unsupported.
  Header: Declared in unknwn.h.

See Also

Custom File and Stream Handlers Overview, Custom File and Stream Handler Interfaces, IAVIEditStream, IAVIFile, IAVIStream, IAVIStreaming, IGetFrame