text: 
  /*
  buddy_status
  Copyright (C) 2010  Belledonne Communications SARL
  
  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License
  as published by the Free Software Foundation; either version 2
  of the License, or (at your option) any later version.
  
  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.
  
  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  */
  
  /**
   * @defgroup buddy_tutorials Basic buddy status notification
   * @ingroup tutorials
   *This program is a _very_ simple usage example of liblinphone,
   *demonstrating how to initiate  SIP subscriptions and receive notifications from a sip uri identity passed from the command line.
   *<br>Argument must be like sip:jehan@sip.linphone.org .
   *<br>
   *ex budy_list sip:jehan@sip.linphone.org
   *<br>Subscription is cleared on SIGINT
   *<br>
   *@include buddy_status.c
  
   *
   */
  
  #ifdef IN_LINPHONE
  #include "linphonecore.h"
  #else
  #include "linphone/linphonecore.h"
  #endif
  
  #include <signal.h>
  
  static bool_t running=TRUE;
  
  static void stop(int signum){
  	running=FALSE;
  }
  
  /**
   * presence state change notification callback
   */
  static void notify_presence_recv_updated (LinphoneCore *lc,  LinphoneFriend *friend) {
  	const LinphonePresenceModel* model = linphone_friend_get_presence_model(friend);
  	const LinphoneAddress* friend_address = linphone_friend_get_address(friend);
  	LinphonePresenceActivity *activity = linphone_presence_model_get_activity(model);
  	char *activity_str = linphone_presence_activity_to_string(activity);
  	printf("New state state [%s] for user id [%s] \n"
  				,activity_str
  				,linphone_address_as_string (friend_address));
  }
  static void new_subscription_requested (LinphoneCore *lc,  LinphoneFriend *friend, const char* url) {
  	const LinphoneAddress* friend_address = linphone_friend_get_address(friend);
  	printf(" [%s] wants to see your status, accepting\n"
  				,linphone_address_as_string (friend_address));
  	linphone_friend_edit(friend); /* start editing friend */
  	linphone_friend_set_inc_subscribe_policy(friend,LinphoneSPAccept); /* Accept incoming subscription request for this friend*/
  	linphone_friend_done(friend); /*commit change*/
  	linphone_core_add_friend(lc,friend); /* add this new friend to the buddy list*/
  
  }
  /**
   * Registration state notification callback
   */
  static void registration_state_changed(struct _LinphoneCore *lc, LinphoneProxyConfig *cfg, LinphoneRegistrationState cstate, const char *message){
  		printf("New registration state %s for user id [%s] at proxy [%s]"
  				,linphone_registration_state_to_string(cstate)
  				,linphone_proxy_config_get_identity(cfg)
  				,linphone_proxy_config_get_addr(cfg));
  }
  
  LinphoneCore *lc;
  int main(int argc, char *argv[]){
  	LinphoneCoreVTable vtable={0};
  
  	char* dest_friend=NULL;
  	char* identity=NULL;
  	char* password=NULL;
  
  	LinphoneFriend* my_friend=NULL;
  
  	/* takes   sip uri  identity from the command line arguments */
  	if (argc>1){
  		dest_friend=argv[1];
  	}
  	/* takes   sip uri  identity from the command line arguments */
  	if (argc>2){
  		identity=argv[2];
  	}
  	/* takes   password from the command line arguments */
  	if (argc>3){
  		password=argv[3];
  	}
  	signal(SIGINT,stop);
  //#define DEBUG
  #ifdef DEBUG
  	linphone_core_enable_logs(NULL); /*enable liblinphone logs.*/
  #endif
  	/*
  	 Fill the LinphoneCoreVTable with application callbacks.
  	 All are optional. Here we only use the both notify_presence_received and new_subscription_requested callbacks
  	 in order to get notifications about friend status.
  	 */
  	vtable.notify_presence_received=notify_presence_recv_updated;
  	vtable.new_subscription_requested=new_subscription_requested;
  	vtable.registration_state_changed=registration_state_changed; /*just in case sip proxy is used*/
  
  	/*
  	 Instantiate a LinphoneCore object given the LinphoneCoreVTable
  	*/
  	lc=linphone_core_new(&vtable,NULL,NULL,NULL);
  	/*sip proxy might be requested*/
  	if (identity != NULL)  {
  		/*create proxy config*/
  		LinphoneProxyConfig* proxy_cfg = linphone_proxy_config_new();
  		/*parse identity*/
  		LinphoneAddress *from = linphone_address_new(identity);
  		LinphoneAuthInfo *info;
  		if (from==NULL){
  			printf("%s not a valid sip uri, must be like sip:toto@sip.linphone.org \n",identity);
  			goto end;
  		}
  		if (password!=NULL){
  			info=linphone_auth_info_new(linphone_address_get_username(from),NULL,password,NULL,NULL,NULL); /*create authentication structure from identity*/
  			linphone_core_add_auth_info(lc,info); /*add authentication info to LinphoneCore*/
  		}
  
  		// configure proxy entries
  		linphone_proxy_config_set_identity(proxy_cfg,identity); /*set identity with user name and domain*/
  		linphone_proxy_config_set_server_addr(proxy_cfg,linphone_address_get_domain(from)); /* we assume domain = proxy server address*/
  		linphone_proxy_config_enable_register(proxy_cfg,TRUE); /*activate registration for this proxy config*/
  		linphone_proxy_config_enable_publish(proxy_cfg,TRUE); /* enable presence satus publication for this proxy*/
  		linphone_address_destroy(from); /*release resource*/
  
  		linphone_core_add_proxy_config(lc,proxy_cfg); /*add proxy config to linphone core*/
  		linphone_core_set_default_proxy(lc,proxy_cfg); /*set to default proxy*/
  
  
  		/* Loop until registration status is available */
  		do {
  			linphone_core_iterate(lc); /* first iterate initiates registration */
  			ms_usleep(100000);
  		}
  		while(	running && linphone_proxy_config_get_state(proxy_cfg) == LinphoneRegistrationProgress);
  
  	}
  
  	if (dest_friend) {
  		my_friend = linphone_friend_new_with_address(dest_friend); /*creates friend object from dest*/
  		if (my_friend == NULL) {
  			printf("bad destination uri for friend [%s]\n",dest_friend);
  			goto end;
  		}
  
  		linphone_friend_enable_subscribes(my_friend,TRUE); /*configure this friend to emit SUBSCRIBE message after being added to LinphoneCore*/
  		linphone_friend_set_inc_subscribe_policy(my_friend,LinphoneSPAccept); /* Accept incoming subscription request for this friend*/
  		linphone_core_add_friend(lc,my_friend); /* add my friend to the buddy list, initiate SUBSCRIBE message*/
  
  	}
  
  	/*set my status to online*/
  	linphone_core_set_presence_model(lc, linphone_presence_model_new_with_activity(LinphonePresenceActivityOnline, NULL));
  
  	/* main loop for receiving notifications and doing background linphone core work: */
  	while(running){
  		linphone_core_iterate(lc); /* first iterate initiates subscription */
  		ms_usleep(50000);
  	}
  
  	/* change my presence status to offline*/
  	linphone_core_set_presence_model(lc, linphone_presence_model_new_with_activity(LinphonePresenceActivityOffline, NULL));
  	linphone_core_iterate(lc); /* just to make sure new status is initiate message is issued */
  
  	linphone_friend_edit(my_friend); /* start editing friend */
  	linphone_friend_enable_subscribes(my_friend,FALSE); /*disable subscription for this friend*/
  	linphone_friend_done(my_friend); /*commit changes triggering an UNSUBSCRIBE message*/
  
  	linphone_core_iterate(lc); /* just to make sure unsubscribe message is issued */
  
  end:
  	printf("Shutting down...\n");
  	linphone_core_destroy(lc);
  	printf("Exited\n");
  	return 0;
  }
  
  