.TH "How-To initialize libeXosip2." 3 "Sun Jun 24 2012" "Version 3.1.0" "libeXosip2" \" -*- nroff -*-
.ad l
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.SH NAME
How-To initialize libeXosip2. \- When using eXosip, your first task is to initialize both eXosip context and libosip library (parser and state machines)\&. This must be done prior to any use of libeXosip2\&.
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.nf

        #include <\fBeXosip2/eXosip\&.h\fP>
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        int i;
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        TRACE_INITIALIZE (6, stdout);
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        i=\fBeXosip_init()\fP;
        if (i!=0)
          return -1;
.fi
.PP
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.nf
        i = eXosip_listen_addr (IPPROTO_UDP, NULL, port, AF_INET, 0);
        if (i!=0)
          {
            \fBeXosip_quit()\fP;
            fprintf (stderr, 'could not initialize transport layer\\n');
            return -1;
          }
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.nf
        \&.\&.\&. then you have to send messages and wait for eXosip events\&.\&.\&.
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In the previous code, you've learned how to: 
.PD 0

.IP "\(bu" 2
Initialize the osip trace (compile this code with -DENABLE_TRACE) 
.IP "\(bu" 2
Initialize eXosip (and osip) stack 
.IP "\(bu" 2
Open a socket for signalling (only UDP with initial eXosip2 version) 
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Now you have to handle eXosip events\&. Here is some code to get \fBeXosip_event\fP from the eXosip2 stack\&.
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.nf

  eXosip_event_t *je;
  for (;;)
    {
      je = eXosip_event_wait (0, 50);
      \fBeXosip_lock()\fP;
      eXosip_automatic_action ();
      \fBeXosip_unlock()\fP;
      if (je == NULL)
        break;
      if (je->type == EXOSIP_CALL_NEW)
        {
        \&.\&.\&.\&.
        \&.\&.\&.\&.
        }
      else if (je->type == EXOSIP_CALL_ACK)
        {
        \&.\&.\&.\&.
        \&.\&.\&.\&.
        }
      else if (je->type == EXOSIP_CALL_ANSWERED)
        {
        \&.\&.\&.\&.
        \&.\&.\&.\&.
        }
      else \&.\&.\&.\&.\&.
      \&.\&.\&.\&.
      \&.\&.\&.\&.
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.nf
      eXosip_event_free(je);
    }
.fi
.PP
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You will receive one event for each SIP message sent\&. Each event contains the original request of the affected transaction and the last response that triggers the event when available\&.
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You can access all headers from those messages and store them in your own context for other actions or graphic displays\&.
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For example, when you receive a REFER request for a call transfer, you'll typically retreive the 'refer-To' header:
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.nf

  osip_header_t *referto_head = NULL;
  i = osip_message_header_get_byname (evt->sip, 'refer-to', 0, &referto_head);
  if (referto_head == NULL || referto_head->hvalue == NULL)
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The \fBeXosip_event\fP also contains identifiers for calls, registrations, incoming subscriptions or outgoing subscriptions when applicable\&. Those identifiers are used in API to control calls, registrations, incoming or outgoing subscriptions\&. These API will build default messages with usual SIP headers (From, To, Call-ID, CSeq, Route, Record-Route, Max-Forward\&.\&.\&.) and send thoses messages for you\&. 
.SH "Author"
.PP 
Generated automatically by Doxygen for libeXosip2 from the source code\&.