pjsip (pjsua) notification when remote user answers the call

Question

I am trying to make a simple SIP user agent using https://github.com/pjsip/pjproject. I can succesfully connect to a sip server (Twilio) and place calls to PSTN numbers using the pjsua_* interface. This works fine.

What I would like now is to get a notification (through a callback or such) from pjsip when the user that I am calling answers the call.

I am using on_call_state() to get updates on the invite, but this goes through the same states

CALLING -> CONNECTING -> CONFIRMED -> DISCONNCTD

even if the user rejects the call. So I guess I am not looking at the right callback for this.

How can I definitely tell if the user has answered or rejected the call?

Answer 1

for me it is working this way. in on_call_state callback:

pjsua_call_info callInfo;
pjsua_call_get_info(call_id, &callInfo);
pjsip_inv_state state = callInfo.state;
pjsip_status_code statusCode = callInfo.last_status;

switch (state) {
.....
case PJSIP_INV_STATE_CONFIRMED:
    // remote party answered the call normally
    break;
case PJSIP_INV_STATE_DISCONNECTED:
    if (statusCode == PJSIP_SC_BUSY_HERE) {
       // rejected
    } else {
       // finished ok
    }
    break;

i reject call this way:

pj_status_t state;
int sendCode = PJSIP_SC_DECLINE;
try {
   state = pjsua_call_answer((pjsua_call_id) call_id, sendCode, nullptr, nullptr);
} catch (...) {
   return -1;
}
return state;