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WIN32_MEMORY_REGION_INFORMATION structure (memoryapi.h)

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Contains information about a memory region. A memory region is a single allocation that is created using a memory allocation function, such as VirtualAlloc or MapViewOfFile.

Syntax

typedef struct WIN32_MEMORY_REGION_INFORMATION {
  PVOID  AllocationBase;
  ULONG  AllocationProtect;
  union {
    ULONG Flags;
    struct {
      ULONG Private : 1;
      ULONG MappedDataFile : 1;
      ULONG MappedImage : 1;
      ULONG MappedPageFile : 1;
      ULONG MappedPhysical : 1;
      ULONG DirectMapped : 1;
      ULONG Reserved : 26;
    } DUMMYSTRUCTNAME;
  } DUMMYUNIONNAME;
  SIZE_T RegionSize;
  SIZE_T CommitSize;
} WIN32_MEMORY_REGION_INFORMATION;

Members

AllocationBase

The base address of the allocation.

AllocationProtect

The page protection value that was specified when the allocation was created. Protections of individual pages within the allocation can be different from this value. To query protection values of individual pages, use the VirtualQuery function.

DUMMYUNIONNAME

DUMMYUNIONNAME.Flags

Represents all memory region flags as a single ULONG value. Applications should not use this field. Instead, test the individual bit field flags defined below.

DUMMYUNIONNAME.DUMMYSTRUCTNAME

DUMMYUNIONNAME.DUMMYSTRUCTNAME.Private

A value of 1 indicates that the allocation is private to the process.

DUMMYUNIONNAME.DUMMYSTRUCTNAME.MappedDataFile

A value of 1 indicates that the allocation is a mapped view of a data file.

DUMMYUNIONNAME.DUMMYSTRUCTNAME.MappedImage

A value of 1 indicates that the allocation is a mapped view of an executable image.

DUMMYUNIONNAME.DUMMYSTRUCTNAME.MappedPageFile

A value of 1 indicates that the allocation is a mapped view of a pagefile-backed section.

DUMMYUNIONNAME.DUMMYSTRUCTNAME.MappedPhysical

A value of 1 indicates that the allocation is a view of the \Device\PhysicalMemory section.

DUMMYUNIONNAME.DUMMYSTRUCTNAME.DirectMapped

A value of 1 indicates that the allocation is a mapped view of a direct-mapped file.

DUMMYUNIONNAME.DUMMYSTRUCTNAME.Reserved

Reserved.

RegionSize

The size of the allocation.

CommitSize

The commit charge associated with the allocation. For private allocations, this is the combined size of pages in the region that are committed, as opposed to reserved. For mapped views, this is the combined size of pages that have copy-on-write protection, or have been made private as a result of copy-on-write.

Remarks

The WIN32_MEMORY_REGION_INFORMATION structure contains information about a single memory allocation. In contrast, the MEMORY_BASIC_INFORMATION structure that is returned by the VirtualQuery function describes a contiguous run of pages within a single allocation that all have the same type, state, and protection. The mapping between WIN32_MEMORY_REGION_INFORMATION fields and memory type values returned by VirtualQuery is as follows:

WIN32_MEMORY_REGION_INFORMATION MEMORY_BASIC_INFORMATION::Type
Private MEM_PRIVATE
MappedDataFile MEM_MAPPED
MappedImage MEM_IMAGE
MappedPageFile MEM_MAPPED
MappedPhysical MEM_MAPPED

Requirements

Requirement Value
Minimum supported client Windows 10, version 1607 [desktop apps only]
Minimum supported server Windows Server 2016 [desktop apps only]
Header memoryapi.h (include Windows.h)

See also

MEMORY_BASIC_INFORMATION

MapViewOfFile

VirtualAlloc

VirtualQuery