What happens if you use "RegisterClass" that is already registered?

[jamie]

Although I have not fully tested this but, the question remains!

 What happens if I register a class of my own that just happens to be already registered but not the same?
 
 This is for use with the streaming system, and I can picture a class being changed from some other part of the app?

Jamie

[Thaddy]

Well, simply try?

Code: Pascal  [Select][+][-]

1. {$ifdef fpc}{$mode objfpc}{$endif}
2. uses classes;
3. type
4. {$M+}
5.   TMyClass = class(TPersistent)
6.   private
7.     FDummy:integer;
8.   published
9.     property dummy:integer read FDummy write Fdummy;
10.   end;
11.  
12. begin
13.   RegisterClass(TMyClass);
14.   RegisterClass(TMyClass);// ergo: nothing happens
15. end.

Delphi says this:
https://docwiki.embarcadero.com/Libraries/Sydney/en/System.Classes.RegisterClass

Registering the same class twice:nothing happens
Registering two classes with the same name:exception is raised.

Test that yourself.