Presence and Instant Messaging

Presence feature in PJSUA2 centers around pj::Buddy class. This class represents a remote buddy (a person, or a SIP endpoint).

Subclassing the Buddy class

To use the pj::Buddy class, normally application SHOULD create its own subclass, such as:

class MyBuddy : public Buddy
    MyBuddy() {}
    ~MyBuddy() {}

    virtual void onBuddyState();

In its subclass, application can implement the buddy callback to get the notifications on buddy state change.

Subscribing to Buddy’s Presence Status

To subscribe to buddy’s presence status, you need to add a buddy object and subscribe to buddy’s presence status. Below is a sample code:

BuddyConfig cfg;
cfg.uri = "";
MyBuddy buddy;
try {
    buddy.create(*acc, cfg);
} catch(Error& err) {

Then you can get the buddy’s presence state change inside the pj::Buddy::onBuddyState() callback:

void MyBuddy::onBuddyState()
    BuddyInfo bi = getInfo();
    cout << "Buddy " << bi.uri << " is " << bi.presStatus.statusText << endl;

For more information, please see pj::Buddy and pj::PresenceStatus.

Responding to Presence Subscription Request

By default, incoming presence subscription to an account will be accepted automatically. Application probably wants to change this behavior, for example only to automatically accept subscription if it comes from one of the buddy in the buddy list, and for anything else prompt the user if he/she wants to accept the request.

This can be done by overriding the pj::Account::onIncomingSubscribe() callback.

Changing Account’s Presence Status

To change account’s presence status, app can call pj::Account::setOnlineStatus() to set basic account’s presence status (i.e. available or not available) and optionally, some extended information (e.g. busy, away, on the phone, etc). Sample code:

try {
    PresenceStatus ps;
    // Optional, set the activity and some note
    ps.activity = PJRPID_ACTIVITY_BUSY;
    ps.note = "On the phone";
} catch(Error& err) {

When the presence status is changed, the account will publish the new status to all of its presence subscribers, either with SIP PUBLISH or NOTIFY request, or both, depending on account configuration.

Instant Messaging(IM)

You can send IM using pj::Buddy::sendInstantMessage(). The transmission status of outgoing IM is reported in pj::Account::onInstantMessageStatus() callback.

In addition to sending instant messages, you can also send typing indication to remote buddy using pj::Buddy::sendTypingIndication().

Incoming IM and typing indication received outside the scope of a call will be reported in pj::Account::onInstantMessage() and pj::Account::onTypingIndication() callbacks.


Use pj::Account::findBuddy() and pj::Account::findBuddy2() to match incoming IM and typing indication to a buddy in the account’s buddy list.