See Also
 Important: |
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This method retrieves an identifier for the pin.
Syntax
HRESULT QueryId( LPWSTR* Id ); |
Parameters
- Id
-
[out] Pin identifier.
Return Value
Returns an HRESULTvalue that depends on the implementation.
HRESULTcan be one of the following standard constants, or other values not listed.
| Value | Description |
|---|---|
|
E_FAIL |
Failure. |
|
E_POINTER |
Null pointer argument. |
|
E_INVALIDARG |
Invalid argument. |
|
E_NOTIMPL |
Method is not supported. |
|
S_OK or NOERROR |
Success. |
Remarks
This method and the IBaseFilter::FindPinmethod allow connections in a filter graph to be saved and restored.
Because pins are identified only by their IPininterface pointers at run time, and pointer information cannot be reliably saved, an identifier is necessary to specify which pins belong to each filter.
The implementation of this method by the pin provides a unique name that the filter graph manager can use to turn into an IPininterface pointer, by calling IBaseFilter::FindPinwhen the filter graph is restored.
The storage is allocated by the filter using the Win32 CoTaskMemAllocfunction. The caller should free it by using CoTaskMemFree.
This method is implemented in the base classes by CBasePin::QueryId.
Requirements
| Windows Embedded CE | Windows CE 2.12 and later |
| Windows Mobile | Pocket PC for Windows Mobile Version 5.0 and later, Smartphone for Windows Mobile Version 5.0 and later |
| Note | Microsoft DirectShow applications and DirectShow filters have
different include file and Library requirements
For more information, see Setting Up the Build Environment,Version 2.12 requires DXPAK 1.0 or later |