IPin::QueryId
| Microsoft DirectShow 9.0 |
IPin::QueryId
The QueryId method retrieves an identifier for the pin.
Syntax
HRESULT QueryId( LPWSTR *Id );
Parameters
Id
[out] Address of a variable that receives a string containing the pin identifier.
Return Value
Returns an HRESULT value. Possible values include the following.
| Value | Description |
| S_OK | Success. |
| E_OUTOFMEMORY | Insufficient memory. |
| E_POINTER | Null pointer argument. |
Remarks
This method supports graph persistence. Use this method to save a pin's state, and the IBaseFilter::FindPin method to restore the state. The pin's identifier string is defined by the filter implementation. The identifier must be unique within the filter.
- **Note **The pin identifier is not necessarily the same as the pin name that the QueryPinInfo method returns.
The filter allocates the returned string using the Microsoft® Win32® CoTaskMemAlloc function. The caller must free it using CoTaskMemFree.
Requirements
Header: Declared in Strmif.h; include Dshow.h.
Library: Use Strmiids.lib.
See Also