withDescriptors(IOMemoryDescriptor **, UInt32, IODirection, bool)
Create an IOMultiMemoryDescriptor to describe a memory area made up of several other IOMemoryDescriptors.
Declaration
static IOMultiMemoryDescriptor * withDescriptors(
IOMemoryDescriptor **descriptors,
UInt32 withCount,
IODirection withDirection,
bool asReference = false );Parameters
- descriptors:
An array of IOMemoryDescriptors which make up the memory to be described.
- withCount:
The object count for the descriptors array.
- withDirection:
An I/O direction to be associated with the descriptor, which may affect the operation of the prepare and complete methods on some architectures.
- asReference:
If false, the IOMultiMemoryDescriptor object will make a copy of the descriptors array, otherwise, the array will be used in situ, avoiding an extra allocation.
Return Value
The created IOMultiMemoryDescriptor on success, to be released by the caller, or zero on failure.
Overview
This method creates and initializes an IOMultiMemoryDescriptor for memory consisting of a number of other IOMemoryDescriptors, chained end-to-end (in the order they appear in the array) to represent a single contiguous memory buffer. Passing the descriptor array as a reference will avoid an extra allocation.