cc_GetDChanState( )

Description | Cautions | Example | Errors | See Also

Name:	int cc_GetDChanState(boarddev, dchstate_buf)
Reference:	LINEDEV boarddev	line device handle for the D channel board
	int *dchstate_buf	pointer to the location where the requested D channel state value is stored
Returns:	0 on success < 0 on failure
Includes:	cclib.h
Category:	System tools
Mode:	synchronous
Technology:	PRI (excluding DPNSS and Q.SIG)

Description

The cc_GetDChanState( ) function retrieves the status of the D channel of a specified board at any time.

Parameter	Description
boarddev:	The line device handle for the D channel board.
dchstate_buf:	Points to the buffer containing the requested D channel state value. The definitions of the possible channel states are:
	DATA_LINK_UP	D channel layer 2 is operable
	DATA_LINK_DOWN	D channel layer 2 is inoperable

Cautions

The cc_GetDChanState( ) function applies only to ISDN PRI technology. For ISDN BRI technology, use the cc_GetDLinkState( ) function.

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()  
{  
  short devhdl;   /* device handle for D channel */  
  int dchanstate; /* the space for cc_GetDChanState output */  
  .  
  .  
  .  
  if ( cc_Open(devhdl,"dtiB1T1", 0 ) < 0 )   
     exit(1);  
   */   
   * Using cc_GetDChanState() to get the   
   * layer 2 status.  
   */  
  if ( cc_GetDChanState(devhdl,&dchanstate) < 0 )  
        procdevfail(devhdl);  
  else if ( dchanstate != DATA_LINK_UP )  
  {  
      printf("D Channel link is inoperable...\n");  
      exit(1);  
  }  
  /* The layer 2 is OK, continue the program. */  
  .  
  .  
  .  
  .  
  .  
  if ( cc_Close(devhdl) < 0 )   
      printf("Error closing device, errno = %d\n", errno);  
}  
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 a value < 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_GetDChanState( ) function include the following:

Error Code	Description
ERR_ISDN_LIB | E_ISBADIF	Bad interface number

See Also

• cc_SetDChanCfg( )

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