Delphi in a Nutshell

Name

TGUID Type

Syntax

type
  TGUID = packed record
    D1: LongWord;
    D2: Word;
    D3: Word;
    D4: array[0..7] of Byte;
  end;

Description

The TGUID type stores a Globally Unique Identifier (GUID). When Windows generates a new GUID, it guarantees that the GUID is unique among all the GUIDs generated throughout the world. Delphi uses GUIDs to identify and look up interfaces.

Tips and Tricks

• Delphi automatically casts an interface name to its GUID, so you can use the interface name in calls to QueryInterface, for example.

• In an interface declaration, write a GUID in square brackets, e.g.:

type IUnknown = interface
  ['{00000000-0000-0000-C000-000000000046}']

• To generate a new GUID in the IDE, press Ctrl-Shift-G.

• GUIDs are optional in interface declarations, but you usually need them. Without a GUID, you cannot cast an interface to another type.

See Also

Interface Keyword, IUnknown Interface, PGUID Type