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PARTITION_INFORMATION_GPT structure

Contains GUID partition table (GPT) partition information.

Syntax


typedef struct _PARTITION_INFORMATION_GPT {
  GUID    PartitionType;
  GUID    PartitionId;
  DWORD64 Attributes;
  WCHAR   Name[36];
} PARTITION_INFORMATION_GPT, *PPARTITION_INFORMATION_GPT;

Members

PartitionType

A GUID that identifies the partition type.

Each partition type that the EFI specification supports is identified by its own GUID, which is published by the developer of the partition.

This member can be one of the following values.

ValueMeaning
PARTITION_BASIC_DATA_GUID
ebd0a0a2-b9e5-4433-87c0-68b6b72699c7

The data partition type that is created and recognized by Windows.

Only partitions of this type can be assigned drive letters, receive volume GUID paths, host mounted folders (also called volume mount points), and be enumerated by calls to FindFirstVolume and FindNextVolume.

This value can be set only for basic disks, with one exception. If both PARTITION_BASIC_DATA_GUID and GPT_ATTRIBUTE_PLATFORM_REQUIRED are set for a partition on a basic disk that is subsequently converted to a dynamic disk, the partition remains a basic partition, even though the rest of the disk is a dynamic disk. This is because the partition is considered to be an OEM partition on a GPT disk.

PARTITION_ENTRY_UNUSED_GUID
00000000-0000-0000-0000-000000000000

There is no partition.

This value can be set for basic and dynamic disks.

PARTITION_SYSTEM_GUID
c12a7328-f81f-11d2-ba4b-00a0c93ec93b

The partition is an EFI system partition.

This value can be set for basic and dynamic disks.

PARTITION_MSFT_RESERVED_GUID
e3c9e316-0b5c-4db8-817d-f92df00215ae

The partition is a Microsoft reserved partition.

This value can be set for basic and dynamic disks.

PARTITION_LDM_METADATA_GUID
5808c8aa-7e8f-42e0-85d2-e1e90434cfb3

The partition is a Logical Disk Manager (LDM) metadata partition on a dynamic disk.

This value can be set only for dynamic disks.

PARTITION_LDM_DATA_GUID
af9b60a0-1431-4f62-bc68-3311714a69ad

The partition is an LDM data partition on a dynamic disk.

This value can be set only for dynamic disks.

PARTITION_MSFT_RECOVERY_GUID
de94bba4-06d1-4d40-a16a-bfd50179d6ac

The partition is a Microsoft recovery partition.

This value can be set for basic and dynamic disks.

 

PartitionId

The GUID of the partition.

Attributes

The Extensible Firmware Interface (EFI) attributes of the partition.

This member can be one or more of the following values.

ValueMeaning
GPT_ATTRIBUTE_PLATFORM_REQUIRED
0x0000000000000001

If this attribute is set, the partition is required by a computer to function properly.

For example, this attribute must be set for OEM partitions. Note that if this attribute is set, you can use the DiskPart.exe utility to perform partition operations such as deleting the partition. However, because the partition is not a volume, you cannot use the DiskPart.exe utility to perform volume operations on the partition.

This attribute can be set for basic and dynamic disks. If it is set for a partition on a basic disk and the disk is converted to a dynamic disk, the partition remains a basic partition, even though the rest of the disk is a dynamic disk. This is because the partition is considered to be an OEM partition on a GPT disk.

GPT_BASIC_DATA_ATTRIBUTE_NO_DRIVE_LETTER
0x8000000000000000

If this attribute is set, the partition does not receive a drive letter by default when the disk is moved to another computer or when the disk is seen for the first time by a computer.

This attribute is useful in storage area network (SAN) environments.

Despite its name, this attribute can be set for basic and dynamic disks.

GPT_BASIC_DATA_ATTRIBUTE_HIDDEN
0x4000000000000000

If this attribute is set, the partition is not detected by the Mount Manager.

As a result, the partition does not receive a drive letter, does not receive a volume GUID path, does not host mounted folders (also called volume mount points), and is not enumerated by calls to FindFirstVolume and FindNextVolume. This ensures that applications such as Disk Defragmenter do not access the partition. The Volume Shadow Copy Service (VSS) uses this attribute.

Despite its name, this attribute can be set for basic and dynamic disks.

GPT_BASIC_DATA_ATTRIBUTE_SHADOW_COPY
0x2000000000000000

If this attribute is set, the partition is a shadow copy of another partition.

VSS uses this attribute. This attribute is an indication for file system filter driver-based software (such as antivirus programs) to avoid attaching to the volume.

An application can use the attribute to differentiate a shadow copy volume from a production volume. An application that does a fast recovery, for example, will break a shadow copy LUN and clear the read-only and hidden attributes and this attribute. This attribute is set when the shadow copy is created and cleared when the shadow copy is broken.

Despite its name, this attribute can be set for basic and dynamic disks.

Windows Server 2003:  This attribute is not supported before Windows Server 2003 with SP1.

GPT_BASIC_DATA_ATTRIBUTE_READ_ONLY
0x1000000000000000

If this attribute is set, the partition is read-only.

Writes to the partition will fail. IOCTL_DISK_IS_WRITABLE will fail with the ERROR_WRITE_PROTECT Win32 error code, which causes the file system to mount as read only, if a file system is present.

VSS uses this attribute.

Do not set this attribute for dynamic disks. Setting it can cause I/O errors and prevent the file system from mounting properly.

 

Name

A wide-character string that describes the partition.

Remarks

The GPT partition format is required for disks that are used to boot computers that use Extended Firmware Interface (EFI) firmware. GPT data disks can reside on x86, x64, and Itanium-based architectures.

For more information about EFI, see Firmware and Boot Environment. Starting with Windows Server 2003 with SP1, GPT is supported on all Windows platforms, not only platforms that use EFI.

Requirements

Minimum supported client

Windows XP [desktop apps only]

Minimum supported server

Windows Server 2003 [desktop apps only]

Header

WinIoCtl.h (include Windows.h)

See also

File System Recognition
IOCTL_DISK_GET_PARTITION_INFO_EX
IOCTL_DISK_SET_PARTITION_INFO_EX
PARTITION_INFORMATION_EX

 

 

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