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4/8/2010

This method retrieves the actual allocator to be used.

Syntax 

HRESULT RequestAllocator(
  IMemAllocator* 
pPreferred,
  ALLOCATOR_PROPERTIES* 
pProps,
  IMemAllocator** 
ppActual
);

Parameters

pPreferred

[in] Preferred allocator.

pProps

[in] Preferred allocator properties (size, count, and alignment).

ppActual

[out] Actual allocator used.

Return Value

Returns an HRESULTvalue that depends on the implementation of the interface. Current DirectShow implementation return values include the following.

Value Description

E_FAIL

Failure to initialize an allocator.

VFW_E_BADALIGN

An invalid alignment was specified.

S_OK

Allocator was returned.

Remarks

The preferred allocator and preferred allocator properties must be passed in. This method returns the actual allocator to be used.

IMemAllocator::GetPropertiesshould be called on the returned allocator to learn the alignment and prefix chosen. This allocator will not be committed and decommitted by the asynchronous reader, only by the consumer. This method must be called before calling IAsyncReader::Request.

Requirements

Windows Embedded CE Windows CE 2.12 and later
Windows Mobile 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