Undeclared identifier: 'PosEx'

I tried to use this code in my program in delphi 2007

function ExtractText(const Str: string; const Delim1, Delim2: string): string;
var
  pos1, pos2: integer;
begin
  result := '';
  pos1 := Pos(Delim1, Str);
  if pos1 > 0 then begin
    pos2 := PosEx(Delim2, Str, pos1+1);
    if pos2 > 0 then
 开发者_开发知识库     result := Copy(Str, pos1 + 1, pos2 - pos1 - 1);
  end;
end;  

I did a search on google i've found that i need "FastCode.Libraries-0.6.4.zip" i download it but don't know how to use it to make the code above works. please help!

---

PosEx is defined in the StrUtils unit. Make sure to include it in your uses clause.