dcb_addtoconf( )

Description | Cautions | Example | Errors | See Also

Name:	int dcb_addtoconf(devh,confid,cdt)
Inputs:	int devh	DCB/SC DSP device handle
	int confid	conference identifier
	MS_CDT *cdt	pointer to conference descriptor element
Returns:	0 on success -1 on failure
Includes:	srllib.h dtilib.h msilib.h dcblib.h
Category:	Conference Management
Mode:	synchronous

Description

The dcb_addtoconf( ) function adds one conferee to an existing conference. The conference identifier specifies the conference to which the conferee will be added. The cdt parameter describes the added conferee.

Parameter	Description
devh:	The DCB/SC DSP device handle.
confid:	The conference identifier number.
cdt:	Pointer to the conference descriptor element.

NOTES:

1. Only one conferee can be added at a time using this function.

2. Invoking this function uses one conferencing resource each time a conferee is successfully added to a conference.

A conference descriptor element has the form of the MS_CDT structure. The format is as follows:

typedef struct {  
          int chan_num;      /* time slot number */  
          int chan_sel;      /* meaning of time slot number */  
          int chan_attr;     /* attribute description */  
} MS_CDT;

The chan_num denotes the SCbus transmit time slot number of the device to be included in the conference. The chan_sel defines the meaning of chan_num. At present, chan_sel must be set to the following value:

• MSPN_TS SCbus time slot

The chan_attr is a bitmask describing the conferee's properties within the conference. Valid choices are:

• MSPA_NULL No special attributes for conferee.
• MSPA_RO Conferee participates in conference in receive-only
  mode.
• MSPA_TARIFF Conferee receives periodic tone for duration of call.
• MSPA_COACH Conferee is a coach. Coach heard by pupil only.
• MSPA_PUPIL Conferee is a pupil. Pupil hears everyone including
  the coach.

Table 3. Valid Attribute Combinations

Pupil	Coach	Periodic Tone	Receive-only mode
			X
		X
		X	X
	X
X
X		X

NOTES:

1. Only one coach and one pupil are allowed in a conference at any time.

2. The default MSPA_NULL must be used if channel attributes are not set.

3. Invalid attribute combinations may lead to unexpected results.

This function returns the SCbus listen time slot number for the MSPN_TS party. The number is placed in the chan_lts field of the MS_CDT structure for the MSPN_TS party. The chan_lts field is defined as follows:

#define   chan_lts     chan_attr

The chan_lts value must be used by the application to listen to the conferenced signal.

Cautions

This function fails when:

• The device handle specified is invalid.
• Too many parties are specified for a single conference.
• The conference ID is invalid.
• DSP resources are not available.

Example

#include <windows.h>  
#include <stdio.h>  
#include "srllib.h"  
#include "dtilib.h"  
#include "msilib.h"  
#include "dcblib.h"  
#include "errno.h"  
#define NUM_PARTIES     2  
main()   
{  
   int  dspdevh;			/* DCB/SC DSP device descriptor   */  
   int  tsdevh1, tsdevh2, tsdevh3;	/* Time slot device descriptor */   
   MS_CDT  cdt[NUM_PARTIES];		/* Conference descriptor table */  
   int  confid;			/* Conference ID */  
   SC_TSINFO tsinfo;		/* Time slot information structure */  
   long  scts;			/* SCbus time slot  */  
   /* Open DCB/SC board 1, DSP 1 device */  
   if ((dspdevh = dcb_open("dcbB1D1",0)) == -1) {  
      printf( "Cannot open dcbB1D1: errno = %d\n", errno);   
      exit(1);  
   }  
   /* Assume DCB/SC is connected to a DTI via SCbus. */  
   /* Open DTI board 1, time slot 1 */  
   if ((tsdevh1 = dt_open("dtiB1T1",0)) == -1) {  
      printf( "Cannot open dtiB1T1: errno = %d", errno);          
      exit(1);  
   }  
   /* Fill in the time slot information structure */  
   tsinfo.sc_numts = 1;  
   tsinfo.sc_tsarrayp = &scts;  
   /* Get the SCbus transmit time slot of tsdevh1 */  
   if (dt_getxmitslot(tsdevh1, &tsinfo) == -1) {  
      printf("Error Message = %s", ATDV_ERRMSGP(tsdevh1));  
      exit(1);  
   }  
   /* Set up CDT structure */  
   cdt[0].chan_num  = (int)scts ;	 /* SCbus transmit time slot */  
   cdt[0].chan_sel  = MSPN_TS ;	 /* returned from dt_getxmitslot() */  
   cdt[0].chan_attr = MSPA_NULL;	 /* Conferee has no special attributes */  
   /* Open DTI board 1, time slot 2 */  
   if ((tsdevh2 = dt_open("dtiB1T2",0)) == -1) {  
      printf( "Cannot open dtiB1T2: errno = %d\n", errno);   
      exit(1);  
   }  
   /* Get the SCbus transmit time slot of tsdevh2 */  
   if  (dt_getxmitslot(tsdevh2, &tsinfo) == -1) {  
      printf("Error Message = %s", ATDV_ERRMSGP(tsdevh2));  
      exit(1);  
   }  
   /* SCbus time slot to be conferenced */  
   cdt[1].chan_num  = (int)scts;		/* SCbus time slot returned */  
   cdt[1].chan_sel  = MSPN_TS;		/* from dt_getxmitslot() */  
   cdt[1].chan_attr = MSPA_NULL;		/* Conferee has no special attributes */  
   /* Establish a 2 party conference */  
   if (dcb_estconf(dspdevh, cdt, NUM_PARTIES, MSCA_ND, &confid) == -1) {  
      printf("Error Message = %s", ATDV_ERRMSGP(dspdevh));  
      exit(1);  
   }  
   /* Open DTI board 1, time slot 3 */  
   if ((tsdevh3 = dt_open("dtiB1T3",0)) == -1) {  
      printf("Cannot open dtiB1T3: errno = %d", errno);   
      exit(1);  
   }  
   /* Do a listen for tsdevh1 */  
   tsinfo.sc_numts = 1;  
   tsinfo.sc_tsarrayp = &cdt[0].chan_lts;  
   if (dt_listen(tsdevh1,&tsinfo) == -1) {  
      printf("Error Message = %s", ATDV_ERRMSGP(tsdevh1));  
      exit(1);  
   }  
   /* Do a listen for tsdevh2 */  
   tsinfo.sc_numts = 1;  
   tsinfo.sc_tsarrayp = &cdt[1].chan_lts;  
   if  (dt_listen(tsdevh2,&tsinfo) == -1) {  
      printf("Error Message = %s", ATDV_ERRMSGP(tsdevh2));  
      exit(1);  
   }  
   /* Fill in the time slot information structure */  
   tsinfo.sc_numts = 1;  
   tsinfo.sc_tsarrayp = &scts;  
   /* Get the SCbus transmit time slot of tsdevh3 */  
   if  (dt_getxmitslot(tsdevh3, &tsinfo) == -1) {  
      printf("Error Message = %s", ATDV_ERRMSGP(tsdevh3));  
      exit(1);  
   }  
   /* Add another conferee to conference */  
   cdt[0].chan_num  = (int)scts;        /* scts is the time slot */  
   cdt[0].chan_sel  = MSPN_TS;  /* returned from getxmitslot*/  
   cdt[0].chan_attr = MSPA_COACH;  
   if (dcb_addtoconf(dspdevh, confid, &cdt) == -1) {  
      printf("Error Message = %s", ATDV_ERRMSGP(dspdevh));  
      exit(1);  
   }  
   else   
      printf("Party added to conference\n");  
   /* Do a listen for tsdevh3 */  
   tsinfo.sc_numts = 1;  
   tsinfo.sc_tsarrayp = &cdt[0].chan_lts;  
   if (dt_listen(tsdevh3,&tsinfo) == -1) {  
      printf("Error Message = %s", ATDV_ERRMSGP(tsdevh3));  
      exit(1);  
   }  
   /* Continue processing */  
   /* Unlisten the time slots */  
   if (dt_unlisten(tsdevh1) == -1) {  
      printf("Error Message = %s", ATDV_ERRMSGP(tsdevh1));  
      exit(1);  
   }  
   if (dt_unlisten(tsdevh2) == -1) {  
      printf("Error Message = %s", ATDV_ERRMSGP(tsdevh2));  
      exit(1);  
   }  
   if (dt_unlisten(tsdevh3) == -1) {  
      printf("Error Message = %s", ATDV_ERRMSGP(tsdevh3));  
      exit(1);  
   }  
   /* Delete the conference */  
   if (dcb_delconf(dspdevh, confid) == -1) {  
      printf("Cannot delete conference %d. Error Message = %s", confid,  
             ATDV_ERRMSGP(dspdevh));  
      exit(1);  
   }  
   if (dt_close(tsdevh1) == -1) {  
      printf("Error closing tsdevh1\n");  
      exit(1);  
   }  
   if (dt_close(tsdevh2) == -1) {  
      printf("Error closing tsdevh2\n");  
      exit(1);  
   }  
if  (dt_close(tsdevh3) == -1) {  
      printf("Error closing tsdevh3\n");  
      exit(1);  
   }  
   if (dcb_close(dspdevh) == -1){  
      printf("Cannot close dcbB1D1. errno = %d\n", errno);  
      exit(1);  
   }  
}

Errors

If the function does not complete successfully, it will return -1 to indicate an error. Use the Standard Attribute functions ATDV_LASTERR( ) to obtain the applicable error value, or ATDV_ERRMSGP( ) to obtain a more descriptive error message.

Refer to the error type tables found in Chapter 2 of this guide. Error defines can be found in dtilib.h, msilib.h or dcblib.h.

See Also

• dcb_delconf( )
• dcb_estconf( )
• dcb_remfromconf( )

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