OCCI AQ Subscription: callback not called

Question

When data changed in table, I want my application to know immediately. So I use the Subsription class. The implements as follows. When I insert row to table set_tab_info, the triggers acts, but the callback not called. What's wrong?
--create multi consumer queue table
BEGIN
dbms_aqadm.create_queue_table (
                                   queue_table => 'hr.table06',
                                   queue_payload_type => 'RAW',
                                   comment => 'multi-consumer',
                                   multiple_consumers => TRUE,
                                   compatible => '8.1.0'
END;
--create multi consumer queue
BEGIN
dbms_aqadm.create_queue (
                              queue_name => 'queue06',
                              queue_table=> 'hr.table06'
END;
BEGIN
dbms_aqadm.start_queue(queue_name => 'queue06');
END;
--create table
CREATE TABLE set_tab_info(
     flag NUMBER
--create trigger, as a test, the payload is a byte
CREATE OR REPLACE TRIGGER tablechangeNew
     AFTER UPDATE OR INSERT OR DELETE
     ON set_tab_info
     FOR EACH ROW
DECLARE
     enqopt dbms_aq.enqueue_options_t;
     mprop dbms_aq.message_properties_t;
     enq_msgid RAW(16);
     rcpt_list dbms_aq.aq$_recipient_list_t;
BEGIN
     rcpt_list(0) := sys.aq$_agent('RECEIVER06', null, null);
     mprop.recipient_list := rcpt_list;
     dbms_aq.enqueue(
                    queue_name => 'hr.queue06',
                    enqueue_options => enqopt,
                    message_properties => mprop,
                    payload => HEXTORAW('61'),
                    msgid => enq_msgid);
END;
#include <iostream>
#include <iomanip>
#include <string>
#include <cstdlib>
#include <vector>
using namespace std;
#include "occi.h"
using namespace oracle::occi;
#include "occiAQ.h"
using namespace oracle::occi::aq;
string username("HR");
string password("HR");
string connstr("192.168.8.22:1521/study");
Environment* p_env = NULL;
Subscription* p_sub = NULL;
Connection* p_conn = NULL;
vector<Subscription> sub_vec;
class NotifyRegister
public:
     static unsigned int callback(Subscription& sub, NotifyResult* nr)
          //nr->getPayload();
          //Message msg = nr->getMessage();
          //Bytes bt =nr->getMessageId();
          cout << "callback was called!" << endl;
          return 0;
     void notifyTest()
          p_env = Environment::createEnvironment(Environment::EVENTS);
          p_sub = new Subscription(p_env);
          p_sub->setSubscriptionNamespace(Subscription::NS_AQ);
          //SCHEMA.QUEUE:CONSUMER_NAME
          p_sub->setSubscriptionName("HR.QUEUE06:RECEIVER06");
          p_sub->setPresentation(Subscription::PRES_DEFAULT);
          p_sub->setProtocol(Subscription::PROTO_CBK);
          p_sub->setNotifyCallback(&NotifyRegister::callback);
          //what's the context mean, how to set?
          p_sub->setCallbackContext((void*)this);
          p_env->enableSubscription(*p_sub);
          p_conn = p_env->createConnection(username, password, connstr);
          sub_vec.push_back(*p_sub);
          p_conn->registerSubscriptions(sub_vec);
int main()
     NotifyRegister nr;
     nr.notifyTest();
     pause();
     return EXIT_SUCCESS;
I don't know how to set the callback context. so just use this statement:
p_sub->setCallbackContext((void*)this);

Answer 1

Thanks, once again. Sorry for my naive questions, but I'm unable to find a good example for this...
After registering the Subscriber, and creating the environment in EVENT mode, it seems like it is picking up the message. Once I send a AQ message, I get an error from visual studio, telling me the variable ESP was not properly saved across a function call. At least it reacts now :)
Could it be that I'm doing something wrong when defining or hooking my callback function? The breakpoint in the callback function is never called....
my registering routine now looks like this:
void aq_connection::create_callback() {
payload = new Bytes(env); //is this the correct way?
Subscription sub(env);
sub.setSubscriptionNamespace(oracle::occi::aq::Subscription::NS_AQ);
sub.setProtocol(oracle::occi::aq::Subscription::PROTO_CBK);
sub.setPayload(*payload);
sub.setCallbackContext((void *)this);
sub.setSubscriptionName(quename + ":" + config->subscribername);
sub.setPresentation(oracle::occi::aq::Subscription::PRES_DEFAULT);
sub.setNotifyCallback(&aq_connection::event_message);
subs.push_back(sub);
conn->registerSubscriptions(subs);
I thought it was ok to create a local Subscription instance, as I put it into the global subs-vector.
Thanks in advance,
Sverre