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CMemAllocator Class

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A version of this page is also available for

Windows Embedded CE 6.0 R3

4/8/2010

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This class provides support for IMemAllocator by using the new operator to allocate memory.

Derived from CBaseAllocator, it overrides the CBaseAllocator::Alloc member function to allocate a single block of memory large enough to hold all requested data areas, and then allocates (using the new operator) a CMediaSample object for each requested buffer pointing into the data area.

The CBaseInputPin and CBaseOutputPin classes instantiate CMemAllocator objects as the default allocator if no other suitable allocator is provided.

All member functions in this class that return HRESULT and accept a pointer as a parameter return E_POINTER when passed a null pointer.

Member Functions

Member function Description

Alloc

Allocates memory for a media sample (overrides CBaseAllocator::Alloc).

CMemAllocator

Constructs a CMemAllocator object.

ReallyFree

Frees memory when called from the destructor (or from Alloc when reallocating for new size or count).

Overrideable Member Functions

Member function Description

Free

Indicates an overridden CBaseAllocator::Free member function, called when a decommit operation is complete to free memory.

Implemented IMemAllocator Methods

Method Description

CreateInstance

Creates new instances of CMemAllocator in the factory template.

SetProperties

Sets the number of media samples and the size of each.

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