// works under Win XP (Win server 2003) or higher
function GetModuleHandleExW(Flags: DWORD; ModuleNameOrAddr: PWideChar; var ModuleHandle: HMODULE): BOOL; stdcall; external kernel32 name 'GetModuleHandleExW';

// with path
function GetDllFileName: UnicodeString;
const
  GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT = 2;
  GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS: DWORD = 4;
var
  ModuleHandle: HMODULE;
  Res: DWORD;
begin
  ModuleHandle := 0;
  SetLength(Result, 32767);
  if GetModuleHandleExW(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS or GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT, @GetDllFileName, ModuleHandle) then
  begin
    Res := GetModuleFileNameW(ModuleHandle, PWideChar(Result), Length(Result));
    if Res = 0 then
      raise Exception.Create('GetModuleFileName fails with error: ' + SysStuff.GetLastOsErrorMessage);
    SetLength(Result, Res);
  end
  else
    raise Exception.Create('GetModuleHandleEx fails with error: ' + SysStuff.GetLastOsErrorMessage);
end;

function GetDllFileName: UnicodeString;
var
  Res: DWORD;
begin
  SetLength(Result, 32767);
  Res := GetModuleFileNameW(HInstance, PWideChar(Result), Length(Result));
  if Res = 0 then
    RaiseLastOSError;
  SetLength(Result, Res);
end;