cc_GetCallInfo( )

Description | Cautions | Example | Errors | See Also

Name:	cc_GetCallInfo(crn, info_id, valuep)
Inputs:	CRN crn	call reference number
	int info_id	call information identifier
	char *valuep	pointer to information buffer
Returns:	0 on success < 0 on failure
Includes:	cclib.h isdnlib.h
Category:	Optional call handling
Mode:	synchronous
Technology:	BRI/2; BRI/SC; PRI (all protocols)

Description

The cc_GetCallInfo( ) function gets the information elements associated with the CRN of an incoming message. The cc_GetCallInfo( ) function must be used immediately after the message is received if the application requires the call information. The library will not queue the call information; subsequent messages on the same line device will be discarded if the previous messages are not retrieved.

NOTE:

For new applications, use the cc_GetSigInfo( ) function instead of cc_GetCallInfo( ). The cc_GetSigInfo( ) function allows buffers to be set up, which enables the application to store and retrieve multiple messages.

Parameter	Description
crn:	The call reference number. Each call needs a CRN.
info_id:	The call information identifier (see Table 19 below).
valuep:	Points to the buffer where the call information will be stored.

The following table provides definitions of possible info_id parameters.

Table 19. cc_GetCallInfo( ) Info_ID Definitions

info_id	Definition
U_IES	Information Elements (IEs) in CCITT format. The cc_GetCallInfo( ) function retrieves all unprocessed IEs in CCITT format. Be sure to allocate enough memory (up to 256 bytes) to hold the retrieved IEs. The IEs are returned as raw data and must be parsed and interpreted by the application. Use IE_BLK to retrieve the unprocessed IEs. For a description of the IE_BLK data structure, see Section 6.6. IE_BLK. See Appendix C for descriptions of information elements specific to the DPNSS protocol.
UUI	User-to-user information. The user information data returned is application-dependent. The user information is retrieved using the USRINFO_ELEM data structure. For a description of the return format for UUI, see Section 6.16. USRINFO_ELEM.

Cautions

• Make sure the size of the information buffer is large enough to hold the string.
• The CCEV_NOFACILITYBUF event will be received by the application for every incoming ISDN message that contains the Network Facility IE. The event is received because the first four IEs are stored in the ISDN library and the remaining ones are discarded. The CCEV_NOFACILITYBUF event can be ignored. The IE can be retrieved using the cc_GetCallInfo(U_IES) function or the cc_GetInfoElem( ) function. The ability to retrieve just the Network Facility IE using the cc_GetCallInfo( ) function is no longer supported.

Example

#include <windows.h>   /* For Windows applications only */  
#include <stdio.h>  
#include <errno.h>  
#include "srllib.h"  
#include "dtilib.h"  
#include "cclib.h"  
void main()  
{  
   LINEDEV   devhdl    = 0;  
   CRN       crn = 0;  
   char     *devname = "dtiB1T1";  
   char      dnis_buf[CC_ADDRSIZE];  
   char      infbuf[MAXLEN_IEDATA];    /* buffer raw information in CCITT format */  
   int       i;         /* for loop counter to print out information buffer contents */  
   /* open the ISDN line device */  
   if ( cc_Open( &devhdl, devname, 0 ) < 0 )   
   {  
        printf("Error opening device: errno = %d\n", errno);  
        exit(1);  
   }  
   printf("Waiting for call\n");  
   if ( cc_WaitCall(devhdl, &crn, NULL, -1, EV_SYNC) < 0 )  
        procdevfail(devhdl);  
   printf("Getting call information\n");  
   if ( cc_GetCallInfo(crn, U_IES, &infbuf) < 0 )  
        callfail(crn);  
   else  
        /* print out the raw buffer information */  
        printf("Received call information buffer contents:\n")  
        for (i=1; i<=MAXLEN_IEDATA; i++) {  
          printf("%c", infbuf[I]);  
        } /* end for */  
   }  
   /* answer the call */  
   if ( cc_AnswerCall(crn, 0, EV_SYNC) < 0 )  
        callfail(crn);  
      .  
      .  
      .  
      .  
      .  
   /* drop the call */  
   if ( cc_DropCall(crn, NORMAL_CLEARING, EV_SYNC) < 0 )  
        callfail(crn);  
   /* release the CRN */  
   if ( cc_ReleaseCall(crn) < 0 )  
        callfail(crn);  
   /* close the ISDN line device */  
   if ( cc_Close( devhdl ) < 0 )   
        printf("Error closing device, errno = %d\n", errno);  
}  /* end main */  
int callfail(CRN crn)  
{                 
        LINEDEV ld;  
        cc_CRN2LineDev(crn,&ld);  
        procdevfail(ld);  
}  
int procdevfail(LINEDEV handle)  
{  
        int reason;  
        char *msg;  
        reason = cc_CauseValue(handle);  
        cc_ResultMsg(handle,reason,&msg);  
        printf("reason = %x - %s\n",reason,msg);  
}

Errors

If the function returns < 0 to indicate failure, use the cc_CauseValue( ) function to retrieve the reason code for the failure. The cc_ResultMsg( ) function can be used to interpret the reason code. Error codes are defined in the files ccerr.h, isdnerr.h, and isdncmd.h.

Error codes from the cc_GetCallInfo( ) function include the following:

Error Code	Description
ERR_ISDN_LIB | E_ISBADCRN	Bad call reference number
ERR_ISDN_LIB | E_ISBADPAR	Bad input parameter
ERR_ISDN_LIB | E_ISNOINFOBUF	Information buffer not ready
ERR_ISDN_LIB | E_ISNOFACILITYBUF	Network Facility buffer not ready

See Also

None

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