dt_getevt( )

Description | Cautions | Example | Errors | See Also

Name:	int dt_getevt(devh,eblkp,timeout) (Windows only)
Inputs:	int devh	D/240SC-T1 or D/300SC-E1 Digital network interface device time slot handle
	EV_EBLK *eblkp	pointer to Event Block Structure
	int timeout	timeout value in seconds
Returns:	0 on success -1 on failure
Includes:	srllib.h dtilib.h
Category:	Parameter Request
Mode:	Synchronous

Description

This dt_getevt( ) function blocks and returns control to the program after one of the events set by dt_setevtmsk( ) occurs on the channel specified in the devh parameter, or a timeout occurs. dt_getevt( ) is used with multi-threaded applications only.

Parameter	Description
devh:	Specifies the valid digital network interface time slot device handle returned by a call to dt_open( )
*eblkp:	Points to the Event Block Structure DX_EBLK, which will contain the event that ended the blocking
timeout:	Specifies the maximum amount of time in seconds to wait for an event to occur. timeout can have one of the following values:   # of seconds: maximum length of time to wait for an event. - when time has elapsed, the function will terminate and return an error   -1: block until an event occurs - the function will not timeout   0: returns -1 immediately if no event is present

NOTE:

When the time specified expires, dt_getevt( ) will terminate and return an error. The Standard Attribute function ATDV_LASTERR( ) can be used to determine the cause of the error, which in this case is EDX_TIMEOUT.

On successful return from the function the event block structure will have the following information.

eblk.ev_dev:	Device on which the event occurred - this will be the same as the devh parameter passed in.
eblk.ev_event:	DTEV_SIG indicates signaling transition event. DTEV_T1ERRC indicates alarm.
eblk.ev_data[ ]:	DTEV_SIG contains information about the signaling event. ev_data[ ] is an array of bytes where ev_data[0] and ev_data[1] contain the signaling information. Retrieve the signaling information in a short variable and see the example below to get the signaling information from ev_data[0] and ev_data[1]. DTEV_T1ERRC contains information about the type of alarm occurring.

The event block structure is defined as follows:

typedef struct ev_eblk {  
   long ev_dev;            /* Device on which event occurred */  
   unsigned long ev_event; /* Event type */  
   long ev_len;            /* Length of data associated with event */  
   char ev_data[8];        /* 8 byte data buffer */  
   void * ev_datap;        /* Variable pointer if more than 8 bytes of  
                              data */  
} EV_EBLK;

Cautions

dt_getevt( ) is only used for multithreaded applications.

Example

#include <windows.h>  
#include <srllib.h>  
#include <dtilib.h>  
#include <errno.h>  
   
EV_EBLK eblk;  
main()  
{  
   int devh;                  /* Board device handle */  
   unsigned short bitmaskp;   /* Bitmask variable */  
   unsigned short sigmsk = DTMM_AON | DTMM_AOFF | DTMM_BON | DTMM_BOFF;  
   short sig, indx;  
   
   /*  
    * Open Timeslot 1 device  
    */  
   if ( ( devh = dt_open( "dtiB1T1", 0 ) ) == -1 ) {  
      printf( "Cannot open timeslot dtiB1T1.  errno = %d", errno );  
      exit( 1 );  
   }  
    if (dt_setevtmsk(ddd, DTG_SIGEVT, sigmsk, DTA_SETMSK) == -1) {  
       printf("%s: dt_setevtmsk DTG_SIGEVT DTA_SETMSK ERROR %d: %s: Mask =  
       0x%x\n",ATDV_NAMEP(ddd),ATDV_LASTERR(ddd),ATDV_ERRMSGP(ddd),sigmsk);  
       dt_close(ddd);  
         exit(1);  
      }  
   /*  
    *  Wait for events on this timeslot  
    */  
   while(1) {  
      dt_getevt ( devh, &eblk, -1 );    /* Wait for ever */  
      sig = eblk.ev_data[0]  |  ( (short) eblk.ev_data[1] << 8 );  
   
   for (indx = 0; indx <4; indx++) {  
      if (!(sig & (0x1010 << indx))) {  
         continue;  
      }  
      switch (sig & (0x1111 << indx)) {  
         case DTMM_AOFF:  
             fprintf(stderr,"A-OFF ");  
             break;  
   
         case DTMM_AON:  
            fprintf(stderr,"A-ON ");  
            break;  
         case DTMM_BOFF:  
            fprintf(stderr,"B-OFF ");  
            break;  
         case DTMM_BON:  
            fprintf(stderr,"B-ON ");  
            break;  
         }    /* End of switch Statement */  
      }  /* end of for statement */  
   } /* end of while statement */  
              .  
              .  
              .  
}

Errors

If the function returns -1, use the SRL Standard Attribute function ATDV_LASTERR( ) to obtain the error code or use ATDV_ERRMSGP( ) to obtain a descriptive error message. The error codes returned by ATDV_LASTERR( ) are:

Equate	Returned When
EDT_BADPARM	Invalid parameter
EDT_SYSTEM	Windows system error
EDT_TMOERR	Timed out waiting for reply from firmware

See Also

• dt_getevtmsk( )

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