Problem mit Strings in DLL

[helgew]

Guten Abend,

Wie bekomme ich es gebacken, Strings global verfügbar zu machen?

Mein Ansatz bisher :

Delphi-Quellcode:

unit GlobalStrings;

interface
  uses
    windows;

type TGlobalString = packed record
  length: WORD;
  hMapObj: THandle;
end;



function SetGlobalString(str: String): TGlobalString;
function GetGlobalString(gstr: TGlobalString): String;
procedure FreeGlobalString(var gstr: TGlobalString);


implementation


function SetGlobalString(str: String): TGlobalString;
var
  pstr : PChar;
begin
  result.length := length(str);
  result.hMapObj := CreateFileMapping(
                INVALID_HANDLE_VALUE,   // use paging file
                nil,                   // default security attributes
                PAGE_READWRITE,         // read/write access
                0,                      // size: high 32-bits
                result.length,              // size: low 32-bits
                'dllmemfilemap'); // name of map object

  pstr := MapViewOfFile(
                result.hMapObj ,     // object to map view of
                FILE_MAP_WRITE, // read/write access
                0,              // high offset:  map from
                0,              // low offset:   beginning
                0);             // default: map entire file
  CopyMemory(pstr,@str[1],result.length);
end;

procedure FreeGlobalString(var gstr: TGlobalString);
begin
  if gstr.hMapObj <>0 then
  begin
    gstr.length := 0;
    CloseHandle(gstr.hMapObj);
    gstr.hMapObj := 0;
  end;
end;

function GetGlobalString(gstr: TGlobalString): String;
var
  pstr : PChar;
begin
  if gstr.hMapObj <> 0 then
  begin
    pstr := MapViewOfFile(
                gstr.hMapObj ,     // object to map view of
                FILE_MAP_READ, // read/write access
                0,              // high offset:  map from
                0,              // low offset:   beginning
                0);             // default: map entire file
    result := string(pstr);
    setlength(result,gstr.length);
  end;
end;

end.

Das ist noch nicht ausgegoren, aber wann muss ich einen solchen String erstellen?