HEAP_INFORMATION_CLASS enumeration (winnt.h)

  • Article

Specifies the class of heap information to be set or retrieved.

Syntax

typedef enum _HEAP_INFORMATION_CLASS {
  HeapCompatibilityInformation = 0,
  HeapEnableTerminationOnCorruption = 1,
  HeapOptimizeResources = 3,
  HeapTag
} HEAP_INFORMATION_CLASS;

Constants

 
HeapCompatibilityInformation
Value: 0
The heap features that are enabled. The available features vary based on operating system. Depending on the HeapInformation parameter in the HeapQueryInformation or HeapSetInformation functions, specifying this enumeration value can indicate one of the following features:


  • A standard heap that does not support look-aside lists.

  • A heap that supports look-aside lists.

  • A low-fragmentation heap (LFH), which does not support look-aside lists.


For more information about look-aside lists, see the Remarks section.
HeapEnableTerminationOnCorruption
Value: 1
The terminate-on-corruption feature. If the heap manager detects an error in any heap used by the
process, it calls the Windows Error Reporting service and terminates the process.

After a process enables this feature, it cannot be disabled.
HeapOptimizeResources
Value: 3

Remarks

To retrieve information about a heap, use the HeapQueryInformation function. To enable features for a heap, use the HeapSetInformation function.

Windows XP and Windows Server 2003:   A look-aside list is a fast memory allocation mechanism that contains only fixed-sized blocks. Look-aside lists are enabled by default for heaps that support them. Starting with Windows Vista, look-aside lists are not used and the LFH is enabled by default.

Look-aside lists are faster than general pool allocations that vary in size, because the system does not search for free memory that fits the allocation. In addition, access to look-aside lists is generally synchronized using fast atomic processor exchange instructions instead of mutexes or spinlocks. Look-aside lists can be created by the system or drivers. They can be allocated from paged or nonpaged pool.

Requirements

Requirement Value
Minimum supported client Windows XP [desktop apps only]
Minimum supported server Windows Server 2003 [desktop apps only]
Header winnt.h (include Windows.h)

See also

HeapQueryInformation

HeapSetInformation