return concatenation string with procedure

Hello,

I created one procedure and i want to return concatenation string out parameter in procedure. below is the code. 

 create or replace procedure GET_REPORTED_BASELINE_COUNT (device_type_id IN number, baseline_id IN number, result_str out varchar2)

AS

stringtext            varchar2(1000);

stringtext1            varchar2(1000);

v_device_type_id      number(20);

v_baseline_id         number(20);

v_code                varchar2(30);

result                number;

result_str            varchar2(30);

cursor c_code is select distinct EC_SERVER_SECURITY_CODE from customer_info;

BEGIN

     open c_code;

     v_device_type_id := device_type_id;

     v_baseline_id := baseline_id;

     loop

          fetch c_code into v_code;

           exit when c_code%NOTFOUND;