[fpc-devel] Found two Delphi incompatibilities

[Michael Van Canneyt]

On Thu, 31 Aug 2006, Sergei Gorelkin wrote:

> Hello,
>
> While porting some Delphi code, I found the following two
> incomatibility issues. Should I report them as bugs?
>
> Sample 1: It compiles both in Delphi and FPC, but FPC executable fails
> at runtime. Delphi inserts temporary string variable and conversion
> (array of char -> string), but FPC treats the pointer literally.

Did you check the '@ returns typed pointer' setting in FPC ?

> -----
> const
>  TestData: array[0..7] of Char = 'abc'#10'def'#0;
>
> procedure Test1;
> var
>  sl: TStringList;
> begin
>  sl := TStringList.Create;
>  sl.Text := string(@TestData[0]);  // <- fails here
>  sl.Free;
> end;
> -----
>
> Sample 2: This one compiles with Delphi (again, it inserts necessary
> conversion Wide -> Ansi), but does not compile with FPC, neither in
> objfpc nor in Delphi mode.
>
> -----
> function Test2: string;
> var
>  buf: array[0..255] of char;
>  len: Integer;
> begin
> { (skipped) I read USB string descriptor into buf. After that,
>  buf[0] contains length of descriptor in bytes, buf[1] = 3,
>  and rest is filled with Unicode chars. Now I want to convert it into
>  ASCII...
> }
>  len := Integer(buf[0]) shr 1;
>  SetString(result, PWideChar(@buf[2]), len-1);
> end;

What is the error ?

Michael.