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OPEN_VIRTUAL_DISK_PARAMETERS structure (virtdisk.h)

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Contains virtual disk open request parameters.

Syntax

typedef struct _OPEN_VIRTUAL_DISK_PARAMETERS {
  OPEN_VIRTUAL_DISK_VERSION Version;
  union {
    struct {
      ULONG RWDepth;
    } Version1;
    struct {
      BOOL GetInfoOnly;
      BOOL ReadOnly;
      GUID ResiliencyGuid;
    } Version2;
  };
} OPEN_VIRTUAL_DISK_PARAMETERS, *POPEN_VIRTUAL_DISK_PARAMETERS;

Members

Version

An OPEN_VIRTUAL_DISK_VERSION enumeration that specifies the version of the OPEN_VIRTUAL_DISK_PARAMETERS structure being passed to or from the VHD functions.

Value Meaning
OPEN_VIRTUAL_DISK_VERSION_1
1
 Use the Version1 member of this structure.
OPEN_VIRTUAL_DISK_VERSION_2
2
 Use the Version2 member of this structure.

Version1

This structure is used if the Version member is OPEN_VIRTUAL_DISK_VERSION_1 (1).

Version1.RWDepth

Indicates the number of stores, beginning with the child, of the backing store chain to open as read/write. The remaining stores in the differencing chain will be opened read-only. This is necessary for merge operations to succeed.

Value Meaning
0
 Do not open for read/write at any depth. This value should be used for read-only operations.
OPEN_VIRTUAL_DISK_RW_DEPTH_DEFAULT
1
 Default value to use if no other value is desired.
n (user-defined)
 This integer value should be the number of merge levels plus one, if a merge operation is intended.

Version2

This structure is used if the Version member is OPEN_VIRTUAL_DISK_VERSION_2 (2).

Windows 7 and Windows Server 2008 R2:  This structure is not supported until Windows 8 and Windows Server 2012.

Version2.GetInfoOnly

If TRUE, indicates the handle is only to be used to get information on the virtual disk.

Version2.ReadOnly

If TRUE, indicates the file backing store is to be opened as read-only.

Version2.ResiliencyGuid

Resiliency GUID to specify when opening files.

Note

The following parameters prefaced Version3 are intended for internal use.

Version3

Version3.GetInfoOnly

Version3.ReadOnly

Version3.ResiliencyGuid

Version3.SnapshotId

Requirements

Requirement Value
Minimum supported client Windows 7
Minimum supported server Windows Server 2008 R2
Header virtdisk.h

See also

About VHD

OpenVirtualDisk

VHD Reference