Microsoft DirectX 8.0 |
The IGraphVersion interface is implemented on the filter graph manager to provide a way for plug-in distributors and applications to know when the graph has changed. If the graph has changed, and the application or plug-in distributor has an interface on a particular filter or pin, it should requery the graph to see if its pointers are still valid, or if there are new ones it should use.
Methods in Vtable Order
IUnknown methods Description QueryInterface Retrieves pointers to supported interfaces. AddRef Increments the reference count. Release Decrements the reference count. IGraphVersion methods Description QueryVersion Retrieves the current graph version number.
Retrieves the current graph version number.
Syntax
HRESULT QueryVersion( LONG *pVersion );
Parameters
- pVersion
- Pointer to the current graph version.
Return Value
Returns an HRESULT value that depends on the implementation. HRESULT can be one of the following standard constants, or other values not listed.
E_FAIL Failure. E_POINTER Null pointer argument. E_INVALIDARG Invalid argument. E_NOTIMPL Method isn't supported. S_OK or NOERROR Success.
Remarks
The version number is incremented every time there is a change in the set of filters in the graph or in their connections. If the version number has changed since the last enumeration, the graph must be re-enumerated.