March 2000
Intermediate to advanced
576 pages
18h 13m
English
Content preview from Delphi in a Nutshell
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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 |
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.