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IPin::QueryId

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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