DOS ain't dead

Not widely known problem in programming? (Developers)

posted by ecm  , Düsseldorf, Germany, 28.03.2021, 21:52

> Program ObjTest;
> type
> test_obj=object
> message:pchar;
> procedure Init;
> procedure Display;
> end;
>
> Procedure test_obj.Init;
> var s:string;        {variable on local stack}
> begin
> s:='Hello'#0;
> message:=@s[1];      {public reference to local stack}
> end;
>
> Procedure test_obj.Display;
> begin
> writeln(message);
> end;
>
> var to:test_object;
> begin
> to.Init;
> to.Display;
> end.

I was curious about the meaning of your example. The FreePascal description of the pchar type confirms my expectation: the #0 inserts a zero terminator into the s variable, and @s[1] makes a pointer to the message data. (I think 0 would point to the string-type object's length counter?)

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l

Complete thread:

• Not widely known problem in programming? - Laaca, 27.03.2021, 20:06 (Developers)
  • Not widely known problem in programming? - ecm, 27.03.2021, 20:30
    • Not widely known problem in programming? - tkchia, 28.03.2021, 08:02
      • Not widely known problem in programming? - marcov, 28.03.2021, 17:44
      • Not widely known problem in programming? - bretjohn, 29.03.2021, 20:03
        • Not widely known problem in programming? - Laaca, 29.03.2021, 22:24
          • Not widely known problem in programming? - bretjohn, 29.03.2021, 23:02
            • Not widely known problem in programming? - marcov, 30.03.2021, 12:05
        • Not widely known problem in programming? - ecm, 29.03.2021, 22:26
  • Not widely known problem in programming? - ecm, 28.03.2021, 21:52
    • Not widely known problem in programming? - Laaca, 29.03.2021, 05:04