Programming Forums > Application Development > Delphi

SittingDuck · Nov 21st, 2005, 11:44 AM

How are unions declared in Delphi? I know they're something like this:

type
	TRecord = record
		case Integer of
			0: (A: Integer);
			1: (B: Single);
	end;

But I don't understand exactly what's going on.

Scorpions4ever · Nov 21st, 2005, 8:32 PM

Pascal is actually a very type-strict language and this is actually one of the documented ways that Wirth himself specified to break type checking. It is part of the PASCAL language specification.

Another way is:

(Toggle Plain Text)

type
	TRecord = record
		case Boolean of
			False: (A: Integer);
			True: (B: Single);
	end;

Nov 21st, 2005, 11:44 AM	#1
SittingDuck Programmer Join Date: Nov 2005 Location: Moseley, Birmingham, England, Earth Posts: 51 Rep Power: 3	Unions How are unions declared in Delphi? I know they're something like this: (Toggle Plain Text) type TRecord = record case Integer of 0: (A: Integer); 1: (B: Single); end; type TRecord = record case Integer of 0: (A: Integer); 1: (B: Single); end; But I don't understand exactly what's going on.

Nov 21st, 2005, 8:32 PM	#2
Scorpions4ever Programmer Join Date: Jun 2005 Posts: 86 Rep Power: 4	Pascal is actually a very type-strict language and this is actually one of the documented ways that Wirth himself specified to break type checking. It is part of the PASCAL language specification. Another way is: (Toggle Plain Text) type TRecord = record case Boolean of False: (A: Integer); True: (B: Single); end; type TRecord = record case Boolean of False: (A: Integer); True: (B: Single); end;

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Programming Forums > Application Development > Delphi

Unions