[fpc-devel] open array and address of "@" / crash, why?

[Martin Frb]

On 30/03/2014 14:35, Jonas Maebe wrote:
> On 30/03/14 15:24, Martin Frb wrote:
>> The below program compiles fine (and generates no warning (fpc 2.6.2 /
>> win 32)
>
> It only compiles fine with the (default) {$t-}. If you add {$t+}, it 
> doesn't compile. Without typed pointers, the result of the @-operator 
> is an untyped pointer, which by definition is assignment-compatible 
> with all other pointer types.
>
> Making {$t+} the default is hard because it could break existing, 
> correct code (e.g., "untypedptr:=@wordvar+1" would result in a pointer 
> 2 bytes after @wordvar instead of 1 with {$t+}).

Ah yes, so easy to forget... (Now I remember)


Slight change, and  I get
Fatal: Compilation aborted


program project1;
{$t+}
type
   TA = array of integer;
   PA = ^TA;
var
   a : array of integer;
   a1: PA;

procedure Foo(var c: array of integer; var c1: PA);
begin
   //c1:= @c;

   writeln( (@c)^[1] );

   //writeln(PInteger(c1)^);
   //writeln(c1^[1]);
   readln;
end;

begin
   SetLength(a,5);
   a[0]:= 100;
   a[1]:= 101;
   a1:=@a;
   foo(a,a1);
end.