[fpc-devel] Bug in PWidechar and refcounting

[Peter Vreman]

> Hi all,
>
> the bug-report on the website doesn't work, so I write a mail:
>
> If you assign a widechar to a pwidechar, the refcount isn't
> increased. This construct is often used in the variants-code, which is
> allowed, according to the comments at the top of wstrings.inc.
>
> An example:
>
> Program test;
>
> var PW    : PWideChar;
>     dummy : AnsiString;
>
> procedure Set_PW;
>
> var
>   W : WideString;
>   s : ansistring;
>
> begin
>   s := 'Hello world'; // Can't assign directly to W, because that's
>   W := s;             // interpreted as a constant with a refcount of -1
>
>   PW := PWideChar(W); // <- Bug, refcount of W (and PW) isn't increased
> end;                  // <- Memory at @W is deallocated, since refcount=0

Kylix doesn't increase the refcount. Add the following line before and
after the assignment to print the refcount:

  writeln(plongint(pchar(w)-8)^);