cc_CRN2LineDev( )

Description | Cautions | Example | Errors

Name:	int cc_CRN2LineDev(crn, linedevp)
Inputs:	CRN crn	call reference number
	LINEDEV *linedevp	pointer to a buffer to store the line device handle
Returns:	0 on success < 0 on failure
Includes:	cclib.h
Category:	System control
Mode:	synchronous
Technology:	BRI/2; BRI/SC; PRI (all protocols)

Description

The cc_CRN2LineDev( ) function is a utility function that matches a CRN to its line device handle. The function returns the line device handle associated with the specified call reference number (CRN).

Parameter	Description
crn:	The call reference number. Each call needs a CRN.
linedevp:	Points to the buffer where the line device handle will be stored.

Cautions

The call reference number (CRN) exists after CCEV_OFFERED is received by the application or cc_MakeCall( ) is issued. The CRN is valid until the cc_ReleaseCall( ) function is issued.

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";  
   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);  
   if ( cc_AnswerCall(crn, 0, EV_SYNC) < 0 )  
        callfail(crn);  
      .  
      .  
      .  
      .  
      .  
   /* Drop the call */  
   if ( cc_DropCall(crn, NORMAL_CLEARING, EV_SYNC) < 0 )  
        callfail(crn);  
   if ( cc_ReleaseCall(crn) < 0 )  
        callfail(crn);  
   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 < 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.

Typically, a < 0 return code for the cc_CRN2LineDev( ) function indicates that the function reference (the CRN) is not valid for the function call.

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