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GUID structure (guiddef.h)

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A GUID identifies an object such as a COM interfaces, or a COM class object, or a manager entry-point vector (EPV). A GUID is a 128-bit value consisting of one group of 8 hexadecimal digits, followed by three groups of 4 hexadecimal digits each, followed by one group of 12 hexadecimal digits. The following example GUID shows the groupings of hexadecimal digits in a GUID: 6B29FC40-CA47-1067-B31D-00DD010662DA.

The GUID structure stores a GUID.

Syntax

typedef struct _GUID {
  unsigned long  Data1;
  unsigned short Data2;
  unsigned short Data3;
  unsigned char  Data4[8];
} GUID;

Members

Data1

Specifies the first 8 hexadecimal digits of the GUID.

Data2

Specifies the first group of 4 hexadecimal digits.

Data3

Specifies the second group of 4 hexadecimal digits.

Data4[8]

Array of 8 bytes. The first 2 bytes contain the third group of 4 hexadecimal digits. The remaining 6 bytes contain the final 12 hexadecimal digits.

Remarks

GUIDs are the Microsoft implementation of the distributed computing environment (DCE) universally unique identifier (UUID). The RPC run-time libraries use UUIDs to check for compatibility between clients and servers and to select among multiple implementations of an interface. The Windows access-control functions use GUIDs to identify the type of object that an object-specific ACE in an access-control list (ACL) protects.

See also

ACCESS_ALLOWED_OBJECT_ACE
ACE
ACL
UUID
UUID_VECTOR

Requirements

Requirement Value
Minimum supported client Windows 10 Build 20348
Minimum supported server Windows 10 Build 20348
Header guiddef.h