Simple Example of Pchar in Delphi DLL

Hi,
I am trying to understand another area of Delphi, that of DLL's and Pointers. In the Documentation that i have read to date, it says that when passing strings to and from a function contained in an extermal  dll, that you either use strings of the shortstring type, or use a pchar as a pointer.

I seem to have some problem with Syntax however, as the following code gives me an error message when i try and compile it.

[E2010 Incompatible types: 'string' and 'PAnsiChar

what am i doing wrong ?
'

library test;
 
{ Important note about DLL memory management: ShareMem must be the
  first unit in your library's USES clause AND your project's (select
  Project-View Source) USES clause if your DLL exports any procedures or
  functions that pass strings as parameters or function results. This
  applies to all strings passed to and from your DLL--even those that
  are nested in records and classes. ShareMem is the interface unit to
  the BORLNDMM.DLL shared memory manager, which must be deployed along
  with your DLL. To avoid using BORLNDMM.DLL, pass string information
  using PChar or ShortString parameters. }
 
uses
  SysUtils,
  Classes,
  Registry,
  Windows;
 
{$R *.res}
 
function getMyDocumentsFolder():Pchar;stdcall;
var
  reg: TRegistry;
  MyDocumentsFolder: Pointer;
begin
  reg := nil;
  try
    reg := reg.Create;
    reg.RootKey := HKEY_CURRENT_USER;
    reg.OpenKey('\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders', false);
    MyDocumentsFolder := reg.ReadString('Personal');
  finally
    reg.free;
  end;
end;
 
exports
 GetMyDocumentsFolder;
 
begin
 
end.

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