This method notifies the input pin as to which allocator the output pin is actually going to use.

HRESULT NotifyAllocator(
  IMemAllocator* pAllocator,
  BOOL bReadOnly


  • pAllocator
    [in] Pointer to the IMemAllocator object to use. This might or might not be the same IMemAllocator object that the input pin provided in the IMemInputPin::GetAllocator method (the output pin could provide its own allocator).
  • bReadOnly
    [out] Flag to indicate if the samples from this allocator are read-only.

Return Values

Returns an HRESULT value that depends on the implementation. HRESULT can 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.


This method is called by the connecting output pin to notify the pin on which this interface is implemented of the allocator it chooses to use for transporting media samples. If the bReadOnly parameter is TRUE, all samples in the allocator are read-only and a copy must be made before modifying any of them.


DirectShow applications and DirectShow filters have different include file and link library requirements. See Setting Up the Build Environment for more information.

OS Versions: Windows CE 2.12 and later. Version 2.12 requires DXPAK 1.0 or later.

See Also

IMemInputPin Interface

Last updated on Wednesday, April 13, 2005

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