dcb_gettalkers( )

Description | Cautions | Example | Errors

Name:	int dcb_gettalkers(devh,confid,numpty,talkers)
Inputs:	int devh	DCB/SC DSP device handle
	int confid	conference identifier
	int * numpty	pointer to number of active talkers
	MS_CDT * talkers	pointer to array of talker descriptions
Returns:	0 on success -1 on failure
Includes:	srllib.h dtilib.h msilib.h dcblib.h
Category:	Auxiliary
Mode:	synchronous

Description

The dcb_gettalkers( ) function retrieves information about the conferees actively talking in the specified conference.

Parameter	Description
devh:	The DCB/SC DSP device handle.
confid:	The conference identifier.
numpty:	Pointer to number of active talkers.
talkers:	Pointer to the array of talker descriptions.

NOTE:

The list is not returned in any specified order.

The returned array of MS_CDT structures contains the active talker descriptions. The array has numpty number of elements. Each MS_CDT structure describes one active talker and has the following format:

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

chan_num contains the transmit time slot number of the actively talking conferee. chan_sel specifies that the conferee is an SCbus time slot.

NOTES:

1. For active talker retrieval, chan_attr is not used.

2. Active talker information is associated with the DSP device handle. The information is invalid upon closing the device.

3. The application is responsible for allocating a table of MS_CDTs large enough to store all the active talkers.

Cautions

This function fails when:

• The device handle specified is invalid.
• An invalid conference ID is specified.

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  
#define   MAX_PTY       32  
main()  
{  
   int  dspdevh;	/* DCB/SC DSP device handle */  
   int  tsdevh1;	/* DTI time slot device handle */  
   int  partycnt;	/* The no. of conferenced parties */  
   int  confid;	/* Conference ID */  
   SC_TSINFO     tsinfo;   /* Time slot information structure */  
   MS_CDT  cdt[MAX_PTY];   /* Conference descriptor table */  
   long  scts;	/* SCbus time slot */  
   int   i;		/* Loop index */  
   /* Open DCB/SC board 1, DSP 1 device */  
   if ((dspdevh = dcb_open("dcbB1D1",0)) == -1) {  
      printf("Cannot open dcbB1D1 : errno = %d", errno);  
      exit(1);  
   }  
   /* Open DTI board 1, time slot 1 device */  
   if ((tsdevh1 = dt_open("dtiB1T1",0)) == -1) {  
      printf("Cannot open dtiB1T1 : errno = %d", errno);  
      exit(1);  
   }  
   /* Open DTI board 1, time slot 2 device */  
   if ((tsdevh2 = dt_open("dtiB1T2",0)) == -1) {  
      printf("Cannot open dtiB1T2 : errno = %d", errno);  
      exit(1);  
   }  
   /* Prepare time slot information structure */  
   tsinfo.sc_numts=1  
   tsinfo.sc_tsarrayp=&scts;  
   /* Get 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, for tsdevh1 */  
   cdt[0].chan_num = (int)scts;    /* SCbus time slot returned */  
   cdt[0].chan_sel = MSPN_TS;      /* ...by dt_getxmitslot() */  
   cdt[0].chan_attr = MSPA_NULL;   /* Conferee has no special attributes */  
   /* Get SCbus transmit time slot of tsdevh2 */  
   if (dt_getxmitslot(tsdevh2, &tsinfo) == -1){  
      printf("Error Message : %s", ATDV_ERRMSGP(tsdevh2));  
      exit(1);  
   }  
   /* Set up CDT structure, for tsdevh2 */  
   cdt[1].chan_num = (int)scts;    /* SCbus time slot returned */  
   cdt[1].chan_sel = MSPN_TS;      /* by dt_getxmitslot() */  
   cdt[1].chan_attr = MSPA_PUPIL;  /* Conferee may be coached later */  
   /* 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);  
   }  
   /* Prepare time slot information structure */  
   tsinfo.sc_numts=1  
   tsinfo.sc_tsarrayp=cdt[0].chan_lts;  
   /* Listen to the time slot returned by dcb_estconf() */  
   if (dt_listen(tsdevh1, &tsinfo) == -1){  
      printf("Error Message : %s", ATDV_ERRMSGP(tsdevh1));  
      exit(1);  
   }  
   /* Prepare time slot information structure */  
   tsinfo.sc_numts=1  
   tsinfo.sc_tsarrayp=cdt[1].chan_lts;  
   /* Listen to the time slot returned by dcb_estconf() */  
   if (dt_listen(tsdevh2, &tsinfo) == -1){  
      printf("Error Message : %s", ATDV_ERRMSGP(tsdevh2));  
      exit(1);  
   }  
   /* Find out who is currently talking */  
   if ((dcb_gettalkers(dspdevh,confid,&partycnt,&cdt)) == -1) {  
      printf ("Error Message = %s", ATDV_ERRMSGP(dspdevh));  
      exit(1);  
   }  
   /* Print out the time slot numbers of currently active talkers */  
   printf ("There are %d currently active talkers\n", partycnt);  
   for (i=0; i<partycnt; i++){  
      printf ("Time slot = %d , Chan_sel = 0x%x\n", cdt[i].chan_num, cdt[i].chan_sel);  
   }  
   /* Remove all time slot listens */  
   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);  
   }  
   /* Delete the conference */  
   if(dcb_delconf(dspdevh, confid) == -1) {  
      printf("Cannot delete conference %d. Error Message = %s", confid,   
              ATDV_ERRMSGP(dspdevh));  
      exit(1);  
   }  
     
   /* Done processing - close all open devices */  
   if (dt_close(tsdevh1) == -1) {  
      printf("Error closing %s : errno = %d\n", ATDV_NAMEP(tsdevh1), errno);  
      exit(1);  
   }  
   
   /* Done processing - close device */  
   if (dt_close(tsdevh2) == -1) {  
      printf("Error closing %s : errno = %d\n", ATDV_NAMEP(tsdevh2), errno);  
      exit(1);  
   }  
   /* Done processing - close device */  
   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.

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