IAsyncReader::RequestAllocator (Windows Embedded CE 6.0)
1/6/2010
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 HRESULT value 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::GetProperties should 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 |
| 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 |